I was going to buy an X554LJ with a Core i5 5200U, 4 GB of RAM and a GT920M on board in one of the stores in my city in the summer of 2016, but at the time of testing it turned out that there was a problem with the keyboard. Perhaps the loop was not fully connected. After 2 weeks, a similar laptop came from a neighboring city, and had no such problems. After another 3 days, I bought a 4 GB RAM from Crucial, since the Samsung bar worked unstably.
By default, Windows 10 Home is installed on this laptop, as evidenced by the sticker under the keyboard and the sticker on the back of the laptop. At first, there were no problems - the system loaded quite quickly from a 500GB HDD, but, as it happens with Windows, this happiness did not last long. Gradually, the speed of the system slipped to unstable.
I solved this problem in the summer of 2017 by installing a 128GB SSD, purchased on AliExpress (and put the HDD through the bay instead of the drive). Windows 10 worked very fast, Visual Studio and other "heavy" programs loaded quickly. In general, there were no complaints ... until once again updates were made and Windows died without the possibility of recovery (and I tried to restore, honestly). Then I discovered the world of Linux on a laptop. About this in more detail below.
There were no problems installing kUbuntu 16.04 - 30 gigabytes were allocated for the system, and 80 gigabytes for the home directory. This miracle worked very quickly. You shouldn’t lead to rubbish on the Internet such as “installing Linux instead of Windows for the sake of increasing productivity” - the same graphical interface works many times faster, there are no problems with Wi-Fi and the system does not require constant installation of updates upon shutdown / reboot. True ... Nvidia in Linux works so-so. It’s better not to install drivers on it.

Actually, now my review: the laptop has a powerful processor (i5 5200U), a small amount of RAM at 4 GB, which can be expanded to 12, and weak graphics GT920M. The hard drive is a narrow neck in this configuration, so immediately after the purchase, you should consider buying an SSD for the laptop. The glossy TN + film screen is a plus for me, since you can completely turn off the backlight (which is valuable hours of battery life) and still see the text on the screen (of course, if the light or the sun shines directly on the screen). At medium brightness in web surfing mode in Win 10 with a balanced mode, the notebook lasts 3-4 hours. The minimum brightness and energy saving will allow you to pull out 5-6 hours. The sound, albeit loud, but terrible in quality - let's say thanks to the quality of the case and the way he likes to rattle. However, after gluing the insides with the same antiskrip, the problem with the sound disappeared. True, there was a problem with the keyboard - when you press the keys, the first one bends, which leaves an unpleasant feeling about the laptop. On this, the pros and cons of the laptop ended, and I conclude my story about him. I hope my experience is useful to someone.

1. RAM 8GB HYNIX HMT41GS6AFR8A-PB DDR3L 1600 SO-DIMM
Tookhere

2. SSD 500Gb - Samsung 860 EVO MZ-76E500BW

3. Slide to replace the optical drive on the Palmexx Optibay HDD9.5mm


The total amount of RAM is 12 GB, when choosing, pay special attention to the voltage of 1.35V (marked as DDR3L ) Perhaps a larger volume will pull, but I did not dare. The memory is well-written here

Independent replacement of difficulties did not cause, although he did everything for the first time. Video disassembly instructions are on YouTube.
After all the manipulations, the laptop got a second life, it turns on quickly, the overall response of the system is more pleasing than after the purchase.

I installed Windows 10 from scratch from an image from the Microsoft website. The license was restored through a Microsoft account registered prior to reinstallation.