Does choice of video card still matter if running linux through virtualization?

[Geshtar]

I'm planning out a new computer build and instead of dual booting Windows/Linux, I've been thinking that with all the VT-x and VT-d extensions + plus VM software maturity now, it would make my life easier and still have good performance in linux if I ran it virtualized from Windows. ( Windows for games, linux for most other things )

I've been doing some research to pick out a video card and it seems like AMD is the way to go on linux if you have more than 2 monitors. I have three monitors, so I am leaning in that direction even though the Nvidia 680 cards seem to have better performance at stock speeds.

So my question is, if you are running a virtualized linux, does it still matter to get a specific brand of card for your needs, or does the virtualization abstract it all away to a generic graphics solution? Does the new VT-d stuff change any of this?

Any one have personal experiences that would be good to know?

Thanks in advance.

 

[jonathonball]

does the virtualization abstract it all away to a generic graphics solution

this

That being said, I have used the multiple monitor support in VirtualBox running Debian Linux (gnome2) with great success. The magic is in the extensions package. Not sure about other VM solutions. I've gotten it to work on the system in sig and on my Core2Duo machine at work.

 

[/dev/null]

If you'd like to try to do this as easily as possible, and you don't know linux, try Xen Cloud Platform (free) or Xenserver (free edition) to pass through graphics to a guest.

 

[402blownstroker]

The support for PCI(e) passthough is getting better and bette all the time, so I would say "Yes it is a consideration." Added a second card in your system and enable PCI passthrough on it for the VB guest. With that done, you can install the actual drivers for the card and get much better performance. With the current support of PCI passthrough, I have had pretty good luck. Definitely looking forward to future improvements.

 

[zandor]

I've been doing some research to pick out a video card and it seems like AMD is the way to go on linux if you have more than 2 monitors. I have three monitors, so I am leaning in that direction even though the Nvidia 680 cards seem to have better performance at stock speeds.

A 680, 670, and probably a 640 can support 4 screens under Linux as a single desktop. A recent change to the drivers added support for >2 screens on Kepler GPUs. IIRC you need version 300 or higher or something like that. I'm pretty sure the 690 can't do 4, but I don't know if it can handle 3 since I don't know if its outputs are split 2-2 or 3-1. They definitely look split though, as every 690 I've looked at has 2 DVI-I and the other Kepler cards only have 1 analog output (either D-sub or DVI-I).

Just in case anyone is wondering about the 610, 620, and 630 -- they're rebadged 400 & 500 series cards and are limited to 2 screens per card in any OS.

The problem with NVidia on Linux is a mix of some new X features not being finished and NV only supporting 2 displays per GPU before Kepler and the new drivers came out. XRandR (I think that's what it's called...) allows you to merge multiple screens into one display, but it can only merge screens on a single GPU. If you want to use more than one card you have to enable Xinerama. That disables XRandR, wrecks your 3D performance, breaks the screen properties settings in a lot of distros (hope you remember how to exit /etc/xorg.conf), and degrades 2D performance. I tried it and found it Xinerama quite usable for pure 2D stuff. Just turn off the 3D desktop acceleration and it runs fine. Getting an AMD card with 3+ outputs was the best way around the problem with X.