Some time ago, I decided to renew my ThinkPad “fleet”. As I travel a lot, I needed a new ultraportable to replace my old X301. Unfortunately, the X301 has several disadvantages like the missing docking port, the abysmal screen, the low performance or the mediocre battery life. First, I thought about getting a T440s or T450s, but some time later, I was able to get a used X240 for less than 400€.
Let’s have a look at the experience I made with the X240 during the last four months. If you want to know if it’s worth buying one or not, just keep on reading 😉
Intel Core i5-4300U (2 cores, 4 threads, 15W TDP, 3M Cache, 1.9 GHz base frequency, 2.6 GHz maximum turbo frequency for two cores, 2.9 GHz maximum turbo frequency for one core)
8GB DDR3L-1600 SDRAM SO-DIMM (one module, single channel, Samsung M471B1G73DB0-YK0)
Intel HD Graphics 4400 (GT2), 20 Execution Units, 1.1 GHz maximum dynamic frequency, supports three independent displays, maximum resolution of an external monitor: 3840×2160 @ 30Hz
1366×768 12.5″ TN (LP125WH2-TPH1), LED backlight, 200 cd/m² brightness, 300:1 contrast ratio (both according to Lenovo, for my own measurements just read on)
If you compare the X240 to older ThinkPads, you might first notice the different color. While most older ThinkPads are black, the chassis of the X240 is slightly brighter and more greyish. Depending on the illumination, the difference may be more or less noticeable. Some ThinkPad fans were complaining about this change, but as the difference isn’t that big in my eyes, I don’t have a problem with it. Another minor difference involves the orientation of the Lenovo and ThinkPad logos on the display cover as they were rotated by 180 degrees. Lenovo also integrated a red status LED into the dot on the i of the ThinkPad logo. Unfortunately, the X240 has only a few other status LEDs. In my opinion, it’s rather disappointing that there are no LEDs for WLAN, WWAN, Caps Lock, the battery status, the charging status or the storage read/write Status. In contrast to the X230, the X240 doesn’t have a wedge profile any more. Instead, it is more built like a rectangular box. You might also notice that the X240 shows even less traces of the traditional ThinkPad clamshell design.
While its predecessor is made of magnesium + PCABS (display cover) and magnesium alloy (bottom), the case of the X240 is made of glass-fiber reinforced plastic (often abbreviated as GFRP), a composite material, plus a Magnesium structure frame in the inside for additional stiffness. With these materials, the X240 feels quite high-class due to the coated display cover and the coated bottom. In contrast to the rubberized coating of older ThinkPads, it doesn’t get dirty that fast and is easier to clean. However, it shares a disadvantage with the rubberized coating of older ThinkPads: at the corners, it wears off quite fast. Unfortunately, the palm rest isn’t coated which makes this part of the chassis feel rather cheap if you compare it to ThinkPads like the T440s or the X301 where the palm rest has some sort of coating as well.
Compared to the X230 (26.6mm at the thickest point), the X240 got a lot slimmer (19mm) while the depth and width are almost identical. In the version without touchscreen, it also weighs a bit less depending on the battery setup:
X230 with 4-cell battery
X240 with no internal battery and 3-cell external battery
X230 with 6-cell battery
X240 with 3-cell internal and 3-cell external battery
X230 with 9-cell battery
X240 with 3-cell internal and 6-cell external battery
Although there are some complaints about the workmanship of newer ThinkPads, my particular one seems to be quite well-built. The clearances between the different parts are quite low and the parts fit well together.
It also feels quite sturdy despite it is only made out of glass-fiber reinforced plastic. Unfortunately, there are still some minor weaknesses left:
Between the hinges (above the battery slot), the bezel can be pushed in slightly
The torsional stiffness of the bottom isn’t perfect
The display cover is quite flexible. I noticed that this leads to marks on the screen because the keys seem to touch the screen. While I saw similar marks on other ThinkPads like the X301, this definitely shouldn’t happen
In contrast to its predecessor, the X240 uses so-called “drop-downhinges“. As the hinges still allow you to fold back the screen by 180 degrees, that’s no disadvantage for me. The hinges hold the display really well and I assume they will last for several years, but the power needed to is quite high. Therefore, you should hold down the base with one hand and open the display with the other hand.
ThinkPads were always known for their easy maintainability. While the X240 is still quite good compared to most consumer Ultrabooks, it definitely is a bit harder to maintain compared to most of the older ThinkPads.
As the following overview shows, replacing some parts got harder compared to its predecessor (steps that are required before the maintenance like unplugging the ac power connector or removing/disabling the batteries aren’t mentioned explicitly):
After removing the base cover (8 screws and some plastic clips that break easily), you have to unscrew three more screws that hold the battery. Unfortunately, the internal battery is no consumer-replaceable unit (CRU), so you might void your warranty if you replace it on your own.
You have to remove the memory module slot cover (two screws). As there are two slots, you can install a maximum of 16GB.
You first have to remove the base cover. The RAM is a CRU, but as there is only one slot, you are limited to 8GB.
You have to loosen one screw that holds the HDD cover.
You first have to remove the base cover (remember, there are eight screws and some plastic clips that can break if you are not careful enough).
You first have to remove the keyboard (two screws) and the palmrest (five screws)
You first have to remove the base cover.
To replace the thermal grease, you need to take the entire device apart (you even need to remove the system board).
After removing the base cover, you need to unscrew four more screws in order to replace the thermal paste.
You have to unscrew two screws
You need to remove the following parts:
WWAN module/M.2 SSD
Furthermore, you have to remove eleven (!) screws.
I appreciate that it is quite easy to replace the thermal paste (as Lenovo applies it mechanically and it is a little bit too thick therefore, this is necessary after some time), as this step is much easier compared to the X230, as shown above. It’s a shame though that replacing the keyboard is that difficult. This is one point where I think that Lenovo should definitely try improve the situation with future generations of ThinkPads.
The ThinkPad X240 offers the typical fare when it comes to the ports. With only two USB 3.0 ports, the X240 offers one USB port less than it’s predecessor, the X230, or most competitors, like the HP Elitebook 820 G1 or the Dell Latitude E7240 (to be fair, the E7240 does not offer VGA, different from the X250, so there is some room that Dell obviously uses to stuff another USB port in there). While that’s no problem for me most of the time because at home, I have a docking station and on the way, I don’t need more than two USB ports most of the time, it is problematic in some cases. For example. I sometime use the X240 with an external screen, an external keyboard and an external mouse at the house of my parents, but (for several reasons) I don’t use a docking station there. If I want to edit some RAW files from my DSLR that still uses Compact Flash cards, I always have to unplug either the keyboard or the mouse to be able to attach the card reader – really impractical. Of couse, it might be an option to carry an USB hub with me, but in my eyes, that’s even more impractical.
Besides the two USB 3.0 ports, the X240 offers a VGA port, a Mini DisplayPort, an Ethernet port, a 3.5mm audio jack and a card reader.
Thanks to a feature called “Daisy Chaining”, you are able to drive multiple displays from the Mini DisplayPort of the X240. However, the X240 has one disadvantage (that may become even more important in the future) that it shares for example with all the other Haswell ThinkPads featuring only the HD Graphics 4400 and almost all ThinkPads of the Ivy Bridge generation except for the W530: displays with a resolution of 3840×2160 (often called “4K”) are only supported at a refresh rate of 30Hz while the maximum resolution at 60Hz is limited to 3200×2000.
Fortunately especially in corporate environments, the X240 still features a VGA port. The resolution via VGA is limited to 1920×1200@60Hz, but I recommend using high quality cables if you want to use that resolution via VGA. I recently tested a 1920×1080 screen (LG Flatron W2442PA) and the quality using a good cable was surprisingly good. I didn’t notice big differences compared to a digital connection via DisplayPort.
The ThinkPad Basic Dock is the cheapest option. It only offers three USB 2.0 ports, one USB 3.0 port, one Ethernet port and one VGA port. Therefore, I do not recommend it because you still have to connect external monitors to the Mini DisplayPort itself in most cases (VGA is no suitable option for screens with higher resolution), which contradicts the principle of a docking station.
Unless you want to connect multiple external monitors without “Daisy Chaining” or a DisplayPort MST hub, I recommend to get the ThinkPad Pro Dock. It offers three USB 2.0 ports, three USB 3.0 ports, one Ethernet port, 0ne DisplayPort 1.2, one DVI-D port, one VGA port and a Stereo/Mic combo audio port. Unfortunately, you can’t use the DisplayPort and the DVI port at the same time. If you want to connect more than one external monitor, you either have to use VGA or a monitor supporting DisplayPort Daisy Chaining or a DisplayPort MST hub (if you don’t want to connect the second monitor to the Mini DisplayPort of the ThinkPad itself).
The ThinkPad Ultra Dock is the most expensive and most versatile option. If you want to connect multiple external monitors (the X240 supports up to three), it is the best choice as it offers three USB 2.0 ports, three USB 3.0 ports, one Ethernet port, two DisplayPort 1.2 outputs, one DVI-D port, one HDMI 1.4 port, one VGA port and one Stereo/Mic combo audio port. Please note that some of the video ports have exclusive use: the first DisplayPort and the HDMI port can’t be used at the same time and the second DisplayPort and the DVI port can’t be used at the same time as well. Therefore, if you want to connect three external monitors, you either have to connect the third monitor via VGA or you have to use Daisy Chaining or a MST hub.
Personally, I own a ThinkPad Pro Dock that I currently use with two external Monitors. Unfortunately, the Pro Dock blocks a part of the fan outlet which leads to higher temperatures (the other available dockingstations share this disadvantage).
Although the X240 itself offers more ports than most typical ultrabooks, I still see some room for improvements:
To be able to connect high-speed storage devices or PCIe-based devices like external GPUs, it would be great if the ThinkPad X260 would have at least one Thunderbolt 3 port. I could even imagine that a Thunderbolt 3 port could replace the “traditional” docking port as well as the power connector because it allows data transfer, support for two 4K 60 Hz displays and quick notebook charging up to 100W with a single cable. In my opinion, Thunderbolt 3 would also be the perfect replacement for the proprietary OneLink port Lenovo uses with some ThinkPads like the X1 Carbon or the ThinkPad Yoga line.
As two USB ports aren’t enough for me sometimes, it would be great if the X260 had three USB 3.1 Type A ports.
When it comes to the wireless connections, the X240 doesn’t leave much to be desired:
Each X240 has two M.2 slots that can be used for wireless devices (depending on the configuration, there might be a third M.2 slot for installing a single-sided M.2 SSD).
The first M.2 slot has a length of 32mm (this format is called M.2 2232) and is used for a WiFi module. My X240 features an Intel Dual Band Wireless-N 7260 with two antennas and a maximum transfer rate of 300 Mbit/s that supports 802.11a/b/g/n and Bluetooth 4.0. Even compared to an Intel 6300 with three antennas, the performance is quite impressive. Unfortunately, I had some connection losses using an older version of the driver, but luckily, they’re gone with the newest version.
The second M.2 slot has a length of 42mm (so its a M.2 2242 slot) and can either be used for a WWAN module or for a small M.2 SSD (acting either as a boot drive or a cache drive). As I travel often, I installed an Ericsson N5321 WWAN module that supports HSPA+. It works really well with Windows 8.1 and the radio reception is much better than with most smartphones, but if you want to change the SIM card often, the flimsy SIM card tray might be an issue.
Optionally, the X240 is available with a fingerprint reader that is made by Synaptics (they acquired Validity Sensors, Inc. two years ago). While it works quite well most of the time, I noticed some problems when my fingers are slightly wet. Unfortunately, these fingerprint readers aren’t too secure: as the Chaos Computer Club showed, even Apple TouchID (that is claimed to be more secure that previous fingerprint technology) can be bypassed easily using “materials that can be found in almost every household”. Therefore, I don’t recommend relying on the fingerprint reader as the only security measure! But even though its not the most secure solution, it certainly is much more comfortable than typing a password in. A great feature, thats even better integrated in Windows with the release of Windows 10 with Windows Hello.
In some configurations, the X240 is equipped with a 720p webcam. Lenovo states that it is “low light sensitive”, but in my experience, images look blurry, noisy and washed out especially under low light conditions. It might be good enough for some Skype calls, but Lenovo should definitely improve this in future generations.
If you have some experience with ThinkPads, you might probably know that the audio quality got slightly worse from generation to generation. Unfortunately, the X240 doesn’t make an exception to this unwritten law. While the maximum volume is still reasonable, the audio quality itself is not good, you could say outright bad.
As its predecessor, the X240 features a 6-row chiclet keyboard. However, Lenovo made some changes compared to the keyboard of the Ivy Bridge generation:
The F keys (F1-12) are separated into groups of four.
The dedicated volume and mute buttons were replaced by buttons that are integrated into the F row (depending on the setting of Fn Lock, these can either be accessed directly or in combination with the Fn key)
There are no Fn combinations for media control (Play/Pause, Previous/Next track) any more.
I must admit that I’m a bit ambivalent. On the one hand, I really appreciate the great typing experience. On the other hand, I’d appreciate a bit more key travel and a 7-row keyboard layout.
Due to the low thickness of the device, Lenovo wasn’t able to use a full-sized keyboard (otherwise, they would have to remove some ports like RJ45 or VGA). Therefore, some keys on the right side of the keyboard are a bit smaller than the others. You might know that from 4:3 12″ ThinkPads like the X40 or the X61 😉
Fortunately, Lenovo fixed one of the most important issues of the keyboard with an UEFI update some time ago: before the update, you always had to press Fn if you wanted to use the combinated End/Insert key even if Fn lock was enabled. After the update, you only have to do so if you disable Fn lock.
Another problem I noticed after using the device for some time: the keys get greasy quite fast, but this may depend on the keyboard manufacturer. Due to the slightly different surface of the keys, that isn’t an issue if you have a keyboard with backlit.
As all Haswell ThinkPads, the X240 features a TrackPoint and a clickpad with integrated TrackPoint buttons. As you might know, a lot of ThinkPad enthusiasts complained about this. As a result, Lenovo decided to reintroduce the dedicated TrackPoint buttons in the current ThinkPad generation.
As usually, the TrackPoint is an awesome pointing device. You should only keep in mind that you should only use the new low profile TrackPoint caps if you don’t want to risk damage to your screen. Currently, these TrackPoint caps are only available as “Soft Dome”. As it’s my favorite cap, it’s no problem for me, but it might be important if you prefer Classic Dome or Soft Rim.
Personally, I must admit that I really like the buttonless clickpad both when using the TrackPoint and when using the touchpad itself. The only issues I noticed when using the integrated TrackPoint buttons while playing some first-person shooters: you aren’t able to press the left and the right “button” at the same time. Apart from that, I am really happy with the integrated TrackPoint buttons. However, if you have some problems with it, you’re still able to replace the clickpad with the new clickpad with dedicated buttons of the X250. Please note that this might void your warranty (at least theoretically).
The touchpad itself is also really good and much better than all the touchpads of previous ThinkPad generations. It is quite big, it supports gestures with up to four fingers, there are a lot of different settings to adjust it to your needs and it offers great sliding properties. Unfortunately, the clickpad becomes shiny after short time.
If you plan to get an X240, you first have to decide if you want a touchscreen or not.
There are three different non-touch displays available:
If you decided to get an X240 with touchscreen, there are only two different display options.
I’d recommend to get the X240 with the Full HD IPS display if your eyesight is good enough (unfortunately, there are still some issues with scaling both under Linux and Windows). As an X240 that already comes with a Full HD display is still quite expensive, you might consider upgrading the display yourself (as I plan to do).
In general, the display is one of the most important user interfaces of a laptop. This is why it is utterly incomprehensible that Lenovo still offers an abysmal 1366×768 TN panel, especially if you keep in mind how expensive the X240 was in my configuration when it was new.
As mentioned above, Lenovo claims that the 1366×768 TN display has a brightness of 200 cd/m² and a contrast ratio of 300:1. While the brightness of my display is slightly higher than 200 cd/m², the contrast ratio is far lower. Everything looks washed out and the measurements confirm my impression of the display.
In my opinion, a display with a maximum contrast ratio of 81:1 is embarassing for a premium business ultraportable.
None of the available displays offers great color space coverage. While the 1366×768 TN panel covers 53,5% of the sRGB color space and 37% of the bigger Adobe RGB color space, the other available panels aren’t significantly better. If you plan to use the X240 for photo editing or other tasks where color fidelity is required, you should always use an external monitor for this reason.
As one might expect from a low quality TN panel, the brightness distribution is quite uneven (82.6%). The brightness differences between the different areas of the screen are even visible with bare eye in some cases. Thanks to the low brightness at the lowest setting (1.98 cd/m²), the display is also suitable for dark environments. Unfortunately, the difference between some of the brightness levels is rather big – I would appreciate some more brightness levels to allow for a finer adjustment of the brightnesss.
Even for a TN panel, the viewing angles are rather bad. Vertically, the colors invert really fast, while it is slightly bether horizontally. Anyway, it leaves a lot to be desired compared to a good IPS panel.
Due to the low maximum brightness and the low contrast ratio, the screen contents are hardly viewable in sunny areas, let alone direct sunlight. However, thanks to the matte surface, the indoor readability is quite good.
According to psref.lenovo.com, the X240 is available with five different dual core CPUs with a thermal design power (TDP) of 15W:
Maximum Turbo Frequency
This unit is equipped with a Core i5-4300U with a base frequency of 1.9GHz and a maximum turbo frequency of 2.9 GHz (single core) and 2.6 GHz (both cores).
Although the i5-3210M I had in my L430 is faster in theory, I didn’t notice any significant performance drop during everyday use. Compared to the X1 Carbon Gen2 with an i7-4550U, the X240 with the i5-4300U is even slightly faster in some benchmarks.
After approximately 30 seconds, the CPU frequency drops from 2.6 GHz to 2.0 GHz during some CPU-intense tasks. After that drop, the frequency cycles between 1900 and 2100 MHz. As the GPU shares the TDP with the CPU, it has the same problem: while the GPU frequency cycles between 1050 and 1100 MHz during the first time and the GPU power is as high as 17W (higher than the TDP), the frequency drops to 750 MHz after that time and the GPU power drops to approx. 8W.
As you might imagine, things are slightly worse when both the CPU and the GPU are used.
At first, the CPU reaches 1900MHz and the GPU cycles between 600 and 1000MHz, but after some time, the frequencies drop to comply with the TDP limit. The CPU frequency then cycles between 600 and 1000MHz (!) and the GPU frequency cycles between 600 and 700 MHz.
Cinebench R10 Rendering Single CPU 64bit
Cinebench R10 Rendering Multiple CPUs 64bit
Cinebench R11.5 CPU Multi 64bit
Cinebench R11.5 CPU Single 64bit
Cinebench R15 CPU Multi 64bit
Cinebench R15 CPU Single 64bit
Super PI 1M
Super PI 2M
Super PI 32M
12 minutes 39 seconds
wPrime 2.10 32M
wPrime 2.10 1024M
The X240 features an Intel HD Graphics 4400 with 20 Execution Units (EU) and a maximum frequency of 1.1 GHz (for some CPUs, the maximum GPU frequency is slightly lower). Although it should be slightly faster than the HD Graphics 4000 in theory, its performance remains behind the possibilities due to the single channel RAM configuration of the X240.
Cinebench R10 OpenGL 64bit
Cinebench R11.5 OpenGL 64bit
Cinebench R15 OpenGL 64bit
If you consider using the X240 for professional applications despite its orientation as an ultraportable “thinbook”, the results of the benchmarks I made using SPECviewperf 12 might be interesting for you. To have some comparison, I added the results of the ThinkPad W540 (both with Quadro K1100M and Quadro K2100M) from spec.org to the table, although that might be a bit unfair 😉
Composite (X240, Intel HD Graphics 4400)
Composite (W540, NVIDIA Quadro K1100M)
Composite (W540, NVIDIA Quadro K2100M)
Siemens NX (snx-02)
As might be expected, the scores are rather low. While you might still be able to do some light CAD work with satisfactory performance, the X240 is definitely the wrong device for intense graphical work.
While you might be able to play some older games like Battlefield 2 at native resolution and maximum settings with decent frame rates, the X240 is rather unsuitable for most newer 3D games as the frame rates are below 30fps even at minimum settings. All frame rates were measured at the native screen resolution of 1366×768.
Metro 2033 (DirectX 9)
Metro 2033 (DirectX 10)
Metro 2033 (DirectX 11)
My unit is equipped with a 180GB Intel SSDSC2BF180A4L 2.5″ SATA SSD that is part of the Intel Pro 1500 series.
While the SSD feels quite fast during everyday use, both sequential read/write speeds and 4K-64 read and write speeds are quite low compared to other SSDs. PCIe-based SSDs like the Samsung PM951 in the X1 Carbon that we reviewed some time ago play in a different league, but even some SATA-bases SSDs like the Samsung 850 Pro are much faster. Therefore, it would be great if the X260 would offer the possibility to use PCIe-based M.2 SSDs.
Thanks to the SSD and the still rather fast CPU, the overall system performance is quite good. Even when editing 22.3MP RAW files from a Canon EOS 5D Mark III in Lightroom or running virtual machines for development purposes, the performance is still reasonable. However, you might notice some performance drops especially in applications that use both the CPU and the GPU over a longer time.
(Please note that all measurements were made at an environment temperature of approx. 28° C!)
During idle or when performing tasks that aren’t too demanding, both the chassis of the device and the CPU stay rather cool.
Things look slightly different under maximum load (Prime95 Small FFTs): the CPU temperature climbs up to 86° C (with the default fan profile) while the chassis temperature reaches up to 51°C in a small area on the bottom around the location of the CPU.
Lenovo made some changes to the fan control with a recent UEFI update that also includes an update for the Embedded Controller (EC) that is in charge of the fan. Before that change, I was quite happy with the fan noise as the device was quiet most of the time, but after the change, the fan became rather annoying because it never stopped to spin even at CPU temperatures lower than 40° C. Another issue I noticed with the fan profile by Lenovo: at high CPU temperatures, the fan is spinning rather slow and it only switches to faster levels at really high temperatures. Therefore, I decided to create a custom fan profile using TPFanControl, but this shouldn’t be necessary because the manufacturer should take care of this.
As most Haswell and Broadwell ThinkPads, the X240 features a concept called “Power Bridge”.
This generally means that there are two batteries:
One internal battery with 3 cells and 23.5 watt hours (12.5″ and 14″ models) respectively 44 watt hours (15.5″ and 15.6″ models). You can also get the machines without the internal battery (then, there is some kind of dummy module installed), but I don’t recommend it because while the ThinkPad is less heavy, you loose a lot of battery life and flexibility.
One external battery that is offered in different sizes. You can choose between three different batteries: one 3-cell battery with the same size as the internal battery (23.5 Wh) and two different 6-cell batteries with either 48 or 72 Wh that protrude out of the bottom of the system.
Originally, my X240 was equipped with a 3-cell internal battery and a 3-cell external battery. Due to some wear, both the internal and the external battery only had about 21 watt hours left. I’m a bit disappointed by the internal 3-cell Li-Polymer battery with cells made by Sony: after only 37 charging cycles, it only has 21.17 watt hours (Wh) out of 23.2 Wh left! If you keep in mind that replacing the internal battery by yourself voids the warranty (at least in theory because it is no CRU), you could definitely expect from Lenovo to use only high quality internal batteries.
During the last months, I mainly used the X240 for web browsing, editing photos with Photoshop CC and Lightroom CC, developing software with Visual Studio and Eclipse and taking notes during lectures at university with OneNote. As I travel a lot by train, I often used the WWAN module. Therefore, you might achieve a higher battery life if you don’t use WWAN because this feature can eat quite a lot of power, especially in areas with bad mobile reception.
On average, I achieved 5 hours 13 minutes of battery life with the 3-cell internal and the 3-cell external battery (5 hours 42 minutes at design capacity).
As I often need more battery life, I recently decided to buy the 6-cell external battery with a capacity of 72 watt hours.
With the 3-cell internal battery (21 watt hours left) and the 6-cell external battery (74 watt hours left), the average battery life according to the “Battery Report” (a nice feature of Windows 8.1) was 11 hours 55 minutes.
I’m really happy with the battery life using the external 6-cell battery, but the battery life with the external 3-cell battery was slightly disappointing to me. As Lenovo usually is quite “optimistic” regarding the battery life, it was no big surprise to me that I wasn’t able to reach the promised maximum of 8.7 hours during normal use, but I expected more as the hardware of the X240 should be quite efficient. With all wireless modules disabled, 50% brightness and almost no CPU load (Battery Eater Reader’s test), I was able to achieve slightly more than 10 hours of battery life (11h 15min at design capacity)) with the two 3-cell batteries, but this scenario is rather removed from reality.
There is one important thing you should do to improve battery life and reduce idle temperatures: activating DIPM (Device Initiated Power Management). The developers of the diagnostics and benchmarking tool SiSoftware Sandra wrote a detailed article about the reason to activate it. In conclusion, the CPU of the X240 is a SoC and therefore, the I/O hub is integrated in to the package, too. This means that the package is only able to go to deep sleep states when all devices of the package sleep. Due to the activation of DIPM (by default, only the Windows power Profile “Power Saver” enables DIPM), the SSD and therefore the PCH and the whole package are going to sleep more often. This greatly reduces idle power consumption and increases battery live. However, you have to modify some registry values to enable DIPM for other power profiles as well in most cases.
Again, I’m a bit ambivalent as the X240 is a good ThinkPad, but it’s far away from perfect. While I really like the nice form factor, the great keyboard, the good battery life and the durability, there are still some disadvantages left like the amount of USB ports, the maximum amount of RAM, the low GPU performance due to the single channel RAM, the low color space coverage of the available screens or the slightly difficult maintenance.
While the X250 solves some of these problems as it supports 16GB RAM and 3840×2160@60Hz, it also shares some of the disadvantages of the X240 as the overall design is very similar.
Although I really like the X240, I therefore recommend waiting for the ThinkPad X260 if you have still some time left for your accession as I hope that it will fix the few issues descried above. If you need a machine right now and can´t wait, the X250 is a pretty good contender.