SLI mode (2 Graphic Cards) slower ?

[Ax]

This seams to be a special Horizons problem because all other games I tested so far improve the frame rate by 40% - 80% in SLI mode.

At 1900 x 1200 res with most setings at max I get a framerate in Tazoon of 26f/sec with a SINGLE activated Nvidia 6800 Ultra.

If I activate SLI mode, so both Nvidia 6800 Ultra render on the same image, the framerate DROP to 18f/sec. Same option settings of the game, same location.

Same test with EQ2 and SWG shows a significant framerate improvement, only Horizons seams to have a problem with SLI.

Any idea what need to be done to make it work properly with Horizons ?

[AA0]

Horizons is not limited by GPU speed, so adding more power isn't really doing anything other than creating issues and other slow downs.
Also 1900x1200 isn't a supported resolution by TG, or so they say

[HratLi]

My understanding is that it's mostly CPU bound. As long as you have about 1gig of ram, and a half way decent Video card, the rest seems to be software rendering and processing that causes the slowdown. Going from a Radeon 9500 to a radeon 9800Pro did almost nothing, but going from a 1.2 ghz machine to a 2 had a major effect. Same with going from 512memory to 1gig, I think that at about 768mb or so it stops making so much of a difference. Not sure what the effect of the new patches are but pre merger those were my experiences.

-HratLi

[Lycaunoss]

My understanding is that it's mostly CPU bound. As long as you have about 1gig of ram, and a half way decent Video card, the rest seems to be software rendering and processing that causes the slowdown. Going from a Radeon 9500 to a radeon 9800Pro did almost nothing, but going from a 1.2 ghz machine to a 2 had a major effect. Same with going from 512memory to 1gig, I think that at about 768mb or so it stops making so much of a difference. Not sure what the effect of the new patches are but pre merger those were my experiences.

-HratLi

In my experience this is exactly true. I built a brand new pc a short while back and kept my vid card the same. I got a tremendous performance boost from the new system because of cpu, ram and hard drive differences. When I switched the video card from a Radeon x700pro to an x1800XL I saw no difference in performance. Well not in Hz anyway.

I'm tempted to say the ram limit might be closer to 2GB than 1 though. Moving from 1GB to 2GB makes a noticable difference. I've watched Hz memory load on my system and it gets to about 1.3GB and stops growing. That's only leaving 700MB for running the rest of my system.

[Joaqim]

Well what I've heared from friends ingame is, that you get best performance at 2GB (in one case there even was a difference with going from 1.5GB to 2GB).
For myself, I run a system with 768MB and can only say that it's way to less and will go for 2GB asap (= with next computer).

[Ulkesh]

i had a noticable difference from 1gb to 2gb. it runs a bit smoother, and takes just a little bit longer (few more ports) for me to get bogged down to the point where i have to relog.