Originally Posted by LesPaulLover
What I've found is that, like I said...it's always console ports (especially poor ones, of course) that don't properly utilize my SLI. I'm sure you know how terrible Skyrim was when it released. Not just in terms of GPU of course, but on my system, it was **PISS POOR**
I'm getting literally DOUBLE the frames now, than I was getting when Skyrim released -- most of this in the past 3 months or so. When Skyrim released I was getting 30-60 fps (outdoors and in cities) ... (40-120fps indoors) Now I get 60-120 frames in the wild, never dip below 45 even on the infamous FPS-crushing steps of Dragonreach, and i get a constant 120+ fps indoors.
It was a joke that Bethesda released their game in such a condition. I only had 20 hours played by february of this year when i tried it again. It's finally the game it should have been thanks mostly to nvidia. Their next driver offers further increased Skyrim performance as well -- the beauty of SLI I'm finding. When Nvidia releases a driver that offers 5% increased performance in a game that often translates to a 10% increase with my dual cards.
In terms of SLI AA a good example would be "Last Remnant" from Square Enix. It, and many other shoddy console ports, only require 50% usage from my cards to max them completely. Running SLI AA -- again, we're talking 8x and **16x supersampling** (this translates to 16x, 32x supersampling since both cards render every frame seperately in SLI AA mode). I can run this level of AA and get either the same framerate or often EVEN HIGHER because rending that much AA forces both of my cards to 99% regardless of the game I'm playing.
Interestingly, another easy way to do this is by enabling 3D vision with just about any title. It almost always forces 99% usage on both GPUs if it's a fully 3D game. Again I wish Nvidia would make this happen all the time. I can run 3D vision in many games with, again, the same frames or increased.
Oh, I know exactly what you're talking about w/Skyrim
However, it wasn't nV that fixed it, it was Bethesda ... the problem was lack of CPU optimizations. The game was getting badly CPU BN'd in many areas. I proved it in the thread above, and by the time the fix came from Bethesda, it was pretty well known what the issue was.
CPU BN is actually very commonly the reason why SLI doesn't get 99% usage on both cards, in part because it adds a significant CPU overhead by it's nature ... but of course it's also possible for the combination of game and drivers (esp. the SLI profile) to not really 'get along' all that well ... sometimes it takes nV a while to get the profile right for the game, or sometimes they never bother.
But aside from problems with the game code requiring excessive CPU usage (as with Skyrim), the 'problem' with low GPU usage in SLI isn't 'shoddy ports', per se. Games basically either 'support AFR', or they don't. Beyond that, it's up to nV to make it work right, not the game maker.
Games played over the internet are also notorious for GPU usage issues, particularly in SLI ... again, typically it's CPU BN there as well, ultimately.
Any game that uses PhysX will reek havoc on your gpu usage, at least what you see in the AB graphs, in part because the 'usage' from physX will not show up in the graphs (it's not 'counted') unless you're using a dedicated card. Also, physX only runs on one GPU, which causes the other card in your SLI set to have to slow down to match the rendering speed of the card that's also doing physX.
So there's really a number of causes of <99% gpu usage in SLI, and it's rare that the issue is because the game maker made a 'shoddy port'. They may not have made it 'difficult enough to run' to be able to max your GPU's without maxing your CPU first, but that's usually the extent of their culpability
Now, as I said above SLI AA has it's occasional uses, and if you can max out a game w/o ever seeing over 50% usage on either card, that might be a scenario where it has some benefit.
But what's really happening in SLI AA is that you're (effectively) just running the game on one card, because both cards are working on the exact same frame, in sync, rather than alternating like regular SLI. So each card is getting maxed out because they're both just working as single cards would work ... with the exception being that each is doing 1/2 of the AA load that you've set (if AA even works for the game, at the level you've set it at), and the two images are blended prior to display.
Like I say, it's also very likely that SLI AA isn't even doing anything (afa actually applying any AA) in many games you're 'forcing' it on, because 'forced' AA is not guaranteed to work, nor is transparency SS or MSAA ... in fact, they DO NOT work ... much more often than they DO.
So if you get an FPS increase by turning on SLI AA, it's because either 1) you've actually turned off the game's AA by forcing a mode it doesn't actually support, or 2) you've helped alleviate a CPU BN by taking the cards out of SLI, which reduces CPU overhead. The latter is the more likely case with an old, easy-to-run game like Last Remnant. If you're 100% CPU BN'd, then SLI can be slower than single-card, due to the SLI CPU overhead, IOW.
One way to check if the 'AA" part of SLI AA is working is to run the game with 32x SLI AA and no TRSSAA, and note your FPS. Then try with 64x SLI AA and 16x SLI TRSSAA, and again note FPS. Did the FPS stay the same? If so, then enabling SLI AA isn't even doing anything aside from basically running the game on one card, and making you think both cards are 'maxed out' because they are both just doing the same frame in sync, not alternating like SLI/AFR... in which case, it's not performing the magic that you think it is ... you can accomplish the same thing by running the game on just one of your two cards
Edit: just did a bit of research on the Last Remnant, and it seems forcing AA only works if you rename the .exe to UT3 ... that may be old info, but give it shot. See if you get the same magic from SLI AA ... when AA actually works in the game.
Both these reviews say you can't force AA in this game through regular means, but the 2nd says you can by renaming the .exe (in which case you'll need to force the SLI AA for UT3 profile, not The Last Remnant profile):
http://www.pcgameshardware.com/aid,679961/Unreal-Engine-3-tested-The-Last-Remnant-graphics-card-review/Practice/Edited by brettjv - 4/10/12 at 9:43am