whats the cpu?, it sounds like you might have intel igp running the game.
and which gpu was older and worse?
M variants are usually pretty weak (like 2x weaker) compared to desktop variants.

Hi, my cpu is a i7 6700hq. I have disabled my intel igp so it could only be the nvidia gpu running the game. My older gpu was a NVS 5100m, and it was also on a laptop. When I played on Rust for exemple with this older gpu, I had ~10 fps with ultra low video config, and with the 950m I am 40~50 fps with medium graphics... And when I watch some review of this laptop/gpu on the net, csgo is working with more than 100 fps :/ It's very strange that csgo is the only game affected.
However, I don't know if it has an impact, when I do a lspci in my terminal, my gpu contains the description "3D controller" and not "VGA compatible controller", as it is with the NVS 51000m.

that is actually strange that csgo runs worse than rust. hard to explain.. have you tried different driver versions? maybe those latest drivers screwed somehting for csgo with mobile gpus?

Yeah, I have a similar problem, not only with CS:GO though. I used to have an FX-8320 along with my GTX 650 and games ran smoothly. But then my 8320 fried my mobo and I had to change both - bought a cheap CPU so I could still use the computer. A Phenom X4 820, which I believe is the culprit of games starting to have lots of frame drops and stuttering. And it's not only games that have a performance hit. It is also possible that my mobo is a problem since it even has serial and parallel ports that nobody uses anymore, lol.

The weird thing is... open-source, OpenGL-optmized games like Xonotic run smoothly with high framerates on max settings. Most of these proprietary engines use some sort of wrapper, even if it is at source code level. I get some minimal stutters with Xonotic once in a while, but then that's the CPU, and it's not as frequent as in CS:GO. Everytime I take a bullet in Ballistic Overkill the framerate drops and I can barely react. Even if I buy more powerful hardware I'm not sure how much performance I'll gain. Maybe it's the drivers...

I also believe it must be an optmization detail from the developers of the game. There's this Unity racing game called Hyper Time Disruptor that runs wonderfully at stable 60 fps, and the Hellpoint demo runs at 10-30 fps. The latter being an open-world RPG, so I think it's expected. It also doesn't allow you to choose graphics options and forces fullscreen even when disabling it through command-line arguments. I like the game, but the low performance ruins the experience.

Hardware is complicated :(

Hi, I've tried the 375.66 driver and that was the same for my fps. I've tried to reinstall the game but it's still the same :/