Afaik, MX150 is extremely entry level. It's like the laptop version of a 1030. My wife has a laptop with an MX250, and she basically uses it for playing visual novel games or 2D games only.

Though 6FPS on minimum for a 10 year old game is lower than I would expect. I wouldn't be surprised if it performed better on Windows, but I probably wouldn't expect any higher than 30fps on low.

Are you sure you're using the official Nvidia drivers and not Noveau? What does it say when you write nvidia-smi in the terminal?

Either way, it is a pretty old and weak card, but it should run better than 6fps on gtav.

Pretty sure that card is way too weak to run GTAV, even on lowest settings.

Source: I have a laptop with an MX150.

That is a very low power entry level mobile card. You will need to run everything at low preset, probably max of 720p resolution.

That card is less powerful than the 1650 Max-Q, which is relatively modern mobile entry level: https://gpu.userbenchmark.com/Compare/Nvidia-MX150-0-vs-Nvidia-GTX-1650-Mobile-Max-Q/m332822vsm790279

I don’t know if the nouveau driver supports Vulkan on this, nor the nvidia driver, but if they don’t, then yes, you’ll get better performance on Windows.

Do you have an iGPU as well?

If that's the case, the mx150 needs to copy over the framebuffer to that one when you use the internal display. Performance can improve with an external display, but don't expect wonders.

There were apparently 2 different MX150 chips with very different power consumption (10w vs 25w), core clocks (937mhz vs 1468mhz), and memory bandwidth (40GB/s vs 48GB/s). I don't think either of these are going to play GTA5 well, but the 10w part is probably much worse. Can you confirm which one you've got?

What laptop is it exactly? I've got that card in my Thinkpad T580 and it sucks big time. Not because of the card itself or because of Linux but because it has some insane thermal targets more or less hardcoded in the firmware.

Technically it's fine. It has Vulkan support. It can run Doom 2016 at 30 fps. But as soon as it starts thermal throttling (and it does so very quickly) it clocks down to the lowest value. That way it even struggles to run Quake 3 at more than 6 or so fps.

Having it on battery power can sometimes get it working for half an hour or so. But sooner or later it will get too hot and only stopping the demanding process for a few minutes will get it to cool down enough.