[ltp] Intel UHD Graphics 620 vs Nvidia MX150?

[Kevin Locke]

On Thu, 2018-03-08 at 10:56 -0800, Rubin Abdi wrote:
> I'm thinking of buying a T480s, and am wondering if anyone here has
> thoughts on running either the Intel UHD Graphics 620 or Nvidia MX150?
> 
> I run Debian Sid. I haven't really had much of a desire to do any sort of
> heavy gaming on my laptop, but have started playing more with WebGL stuff
> (particularly Fusion 360 in the browser). I often need to start up a
> Windows VM to verify some cross browser things for work.

I don't have any advice on the T480/T480s specifically, but I am
running Debian testing on a T430 which has both an Intel HD Graphics
4000 and NVIDIA NVS 5400M (with nVidia Optimus) so I'll provide a few
thoughts.

> Anyhow, I guess my questions are, is one GPU more of a pain under linux
> than the other, and is the performance gain from the MX150 noticeable
> enough?

With the exception of a BIOS-related X2APIC issue on boot[1] which
appears when enabling the nVidia card, and lack of decent support for
Optimus[2], I haven't had any significant pains.  They do have the
typical Intel/nVidia trade-offs:

- nVidia driver supports CUDA, both support OpenCL.
- nVidia driver supports VDPAU/NVDEC, Intel driver supports VA-API
  (some gallium drivers support VDPAU and either can be used as a
  backend for the other at some performance cost, as I understand.)
- Different OpenGL vendor extensions between nVidia binary driver and
  Mesa.

The nVidia binary drivers have higher performance at the cost of
tainting the kernel, lagging support for APIs introduced by the
open-source DRM/X.org drivers, and all the costs that generally come
with closed-source software.  I'm not aware of any major pain points
currently.  All drivers seem well-supported by applications.

I generally disable the nVidia card in the BIOS to conserve battery,
since I only use it when playing FPS games, which is rare.  The Intel
card can even do that to some degree (very low settings on semi-recent
games), and it does fine with less demanding 3D apps like WorldWind,
Google Earth, and the WebGL Experiments[3][4].  I haven't seen any
performance issues with video decoding or other non-3D uses.

I have tried enabling 3D acceleration in VirtualBox a few times over
the years and found that it generally had too many issues
(particularly stability and screen corruption issues) to be workable.
I wouldn't recommend it.  Dual booting works fine, of course.

Cheers,
Kevin

1.  https://bugzilla.kernel.org/show_bug.cgi?id=56051
2.  There is https://www.bumblebee-project.org/ and the native support
    keeps improving, but both are still less preferable than
    enabling/disabling the cards in the BIOS for my typical uses.
3.  https://experiments.withgoogle.com/chrome?tag=WebGL
4.  Note: My Intel card lacks GL_ARB_gpu_shader5 so can't run some
    experiments.