..:: PCSX2 Forums ::..

Full Version: What is the CrossFire/SLI support like?
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
Does it have a positive/negative/neutral affect on fps? Does it introduce new bugs?
I am no expert but currently CrossFire/SLI aren't used or supported. I believe PCSX2 simply uses the main GPU and ignored the other. I have not heard of any issues with having a dual GPU system and using PCSX2.

Scootaloo

I'm not familiar with CrossFire/SLI. Are you able to select one over the other or is it treated as one GPU?
The SVN versions allow you to go in the GSdx plugin settings and select the gpu to be used.
I'm not an expert in crossfire/sli either, but when I lived with my roommate he had dual nvidia 680 and there was a setting in the nvidia settings for "older" games that could force sli to alternate rendering frames - at your own peril.
PCSX2 doesn't officially support Xfire/SLI. It probably won't for some time, or ever. There was someone here earlier this year who was toying with custom profiles and he made a little progress, but generally it's not worth the hassle. Modern day mid-tier and above GPU's are just fine for PCSX2 emulation.
I use a dual GPU and it runs fine.
The primary benefit of crossfire/sli is in additional GPU and shader cores. PCSX2 does not make a whole lot of use of either due to how PS2 graphics works (PS2 had small but very fast V-ram and just constantly uploaded new data which is the antithesis of PC hardware which is lots of V-ram with a relatively slow ((not compared to PS2, but in general)) bandwidth meant to hold lots of video data at a time). SLI/xfire does not improve on memory bandwidth.

Since current SLI/xfire implementations work on the principle of processing 1 frame each (or half of each frame, still the same principle) each GPU has to have an exact copy of everything into each GPUs ram. That means transfers have to be identical, filling up each GPU with identical data and squandering any bandwidth improvements that could technically be possible.

With a lot of tweaking, it may be possible to get something to work... but the benefit would be minimal and the chance of graphical glitches increases dramatically.