8800GT in SLi perform the same as one card

[xbobmx]

Are you using the games in fullscreen mode, at the same resolution as your desktop?

If the game changes resolution with the XF86VidMode extension, it actually turns on pan/scan mode with a virtual desktop and pans to the upper left corner. In this mode (or equivalently if the game is in a window), the card doesn't flip and SLI probably won't work very well.

In order to avoid this, set your desktop to the same resolution as your game before starting the game, using nvidia-settings or xrandr (these actually resize the desktop, instead of having a virtual desktop larger than your resolution). And run the game in fullscreen mode.

Or, you could get a Quadro which will flip for non-fullscreen apps =).

See chapter 20 (Configuring Flipping and UBB) of the README.

[gbil]

OK here are my crazy results with ETWQ demo 1.1

I've recorded a small demo (about 10 seconds) which I played in every SLI mode setting com_unlockfps 1 before in order to unlock fps above 30. The resolution is 1680x1050, high quality using my 2x GT8800 512MB cards

AFR: SLI HUD appears but there is no movement, 25.7fps

SFR: SLI bar appears *and* stays in the middle meaning (according to docs) that SLI is working and the load is split between the 2 cards. But.... 21.4 fps !!!

AA: SLI presents x8 AA and... 37.6 fps !!!!!!

I don't know what assumptions to make anymore!

[Deanjo]

Originally Posted by xbobmx

Are you using the games in fullscreen mode, at the same resolution as your desktop?

If the game changes resolution with the XF86VidMode extension, it actually turns on pan/scan mode with a virtual desktop and pans to the upper left corner. In this mode (or equivalently if the game is in a window), the card doesn't flip and SLI probably won't work very well.

In order to avoid this, set your desktop to the same resolution as your game before starting the game, using nvidia-settings or xrandr (these actually resize the desktop, instead of having a virtual desktop larger than your resolution). And run the game in fullscreen mode.

Or, you could get a Quadro which will flip for non-fullscreen apps =).

See chapter 20 (Configuring Flipping and UBB) of the README.

Yes games and desktop are set to the same resolution.

[m3the01]

Im pretty convinced sli and quad sli is not working on
kernel 2.6.18-92.1.6.el5

Using any of the current/beta drivers. I do get the best performance out of the latest 177 beta drivers, but everything is running on one card even though nvidia-settings show quad sli i get no headsup display on any opengl program i run.

This is using a xfx 790i ultra motherboard and 2-9800 GX2's,

[Deanjo]

Does anybody have a confirmed working sli setup with a 750/780/790 series motherboard?

[gbil]

Originally Posted by Deanjo

Does anybody have a confirmed working sli setup with a 750/780/790 series motherboard?

Well as you saw in my posts SLI is working but not good - only AA gives good results, AFR and SFR don't - and that's why I had opened my bug report with no answer yet from NVidia.

NVidia, we would love a comment here!

[Deanjo]

Originally Posted by gbil

NVidia, we would love a comment here!

Yes we most certainly would.

[Deanjo]

I fired off a bug report to linux-bugs@nvidia.com as well now. Hopefully we will see some sort of response.

[gbil]

Originally Posted by Deanjo

I fired off a bug report to linux-bugs@nvidia.com as well now. Hopefully we will see some sort of response.

I've done that weeks ago for the bug I reported for SLI under wine which now seems to be more general and got no answer.

Therefore I inform everyone here and the moderators that the next step is to spam the NVidia representatives in the forum with PM's.

I've also send an email to phoronix, maybe they can get an answer from NVidia.

[Deanjo]

Well I got a reply from nvidia and they are looking into it.

Hello Dean,

That's strange. The X server log shows that SLI is enabled.
Does it make a difference if Option SLI=on is used? I'll try to reproduce this issue in the next couple of days.

Thanks,
Roland

I'll keep folks apprised as to the progress. (BTW his suggestion to set the sli to on didn't change anything).

[gbil]

Originally Posted by Deanjo

Well I got a reply from nvidia and they are looking into it.



I'll keep folks apprised as to the progress. (BTW his suggestion to set the sli to on didn't change anything).

Great, please keep as updated because I never got an answer.

[m3the01]

Would i cant believe we get no response at all on any of the forums....

I really hope something is done soon, cause nvida use to be the bomb on linux, their kick ass just step up and fix dem drivers :-)