2560x1440 144hz - 2 way vs 3 way SLI

[Alexkaneaster]

I recently put together a 3 way sli gtx 980 classified build. This is the first time I've gone 3 way sli, it's always been 2 way sli in the past. Currently I'm gaming on a 1920x1080 144hz monitor, but I'm expecting a rog swift 2560x1440 monitor any time now.

Here's the problem. Benchmarking has been fine, but performance in games with 3 way sli has been awful. In Assassins Creed Brotherhood for example I'm getting around 90 fps with 3 way sli, 120-140 with 2 way sli. In Far Cry 4, the fps is about the same both ways, but it's almost unplayable in 3 way sli. I know from research that a third card is worthless for 1920x1080....I know this. I just didn't expect these problems. Some games really are just unplayable...buggy messes. I've read you start to actually benefit from a third card, if only a little, when you go above 1920x1080. Can anyone verify this?

If 3 way sli is going to be this big of a problem, I need to get rid of one card. I really don't want to do that though. I'll be honest, it looks freaking awesome and I've got a water cooling build just about done. I'm wondering if things smooth out and get better with 3 cards with resolutions higher than 1920x1080, or if 3 way sli just isn't going to work out. I've seen a lot of 3 way builds out there, so I've just assumed they work.

 

[unknownofprob]

three way SLI scaling isn't the best and as far as some games go the performance can be worse as you are experiencing.

Other games do not have this problem, some do. The more popular titles have three way SLI optimized pretty well, though expect more micro-stuttering.

Also : What motherboard and CPU do you have? The third card may be running in X4 mode, making it not worth even having.

 

[bystander]

3-way SLI definitely has problems at times. Not only do some games not support it well, but it puts a little more stress on the CPU to keep up, and if you are already CPU bound, which many games are when trying to reach 100+ FPS, you further stunt your GPU performance. Any time your 3-way SLI has similar performance as 1 or 2 cards, you have increased latency. 50 FPS on a single card has the same latency as 100 FPS in SLI, and 150 FPS in 3-way SLI. Though the higher FPS is smoother, it isn't better in all ways. The time to render any given frame is the same in SLI or not when you have perfect 100% scaling. If you aren't getting that, latency increases.

 

[Alexkaneaster]

I'm running with a rampage iv black and 4960x. Here's the deal, I'm ok if the third card doesn't increase my fps in all games. If I get more fps in some games, great. What I absolutely cannot have is less fps going 3 way and I would going 2 way. I have no problem admitting I'm doing it because its totally bada**. I've been planning a water cooling build for a while and I'm so close to being done. But if the third card is going to hurt my fps...I can't have that, need to get rid of it.

 

[unknownofprob]

some games will benefit, some games will suffer, some games will have terrible micro-stuttering and some games you won't notice anything at all.

Three cards will benefit in quite a few popular titles but stuttering is prone in a few, in that case you might as well stick with three and not two!

 

[bystander]

What you should try, in at least some of those games, is to give up on the idea of 144 FPS. While you can in some games, some games will be CPU bound (quite a lot actually), but you can take advantage of the GPU's by turning up settings. G-sync may allow for variable refreshes up to 144 FPS, but due to it being variable, you really don't need that many. For me, the sweet spot is 85 FPS, and with G-sync, that would be my goal, not 144. At which one, 2-way SLI would be enough as is.

 

[Alexkaneaster]

I didn't consider gsync as a factor. Let me know if I have this wrong, but you're thinking gsync might offset the drop in fps in some games caused by 3 way sli? Honestly I don't really care about 144 fps, doesn't matter. What I don't want is a huge drop in fps just because I'm going 3 way. And with the micro stuttering...I haven't really experienced that too much. Will gsync help with that or not? I haven't had any hands on experience with gysnc yet.

 

[bystander]

No, G-sync won't help stop the FPS drops, but it may make them feel a little less jarring, as the refresh will sync with them. That said, the more GPU's you have, the more FPS drops you'll experience. The reason is that most large FPS drops are CPU related, not GPU related. With more GPU's, you hit the CPU ceiling a lot more.

 

[Alexkaneaster]

Sorry, I mean the noticeable effect of fps drops, not the actual fps drops. If it's less noticeable, I can accept that sometimes. You think I'm hitting the 4960x ceiling with 3 980's? I hope not, darn thing was expensive.

 

[bystander]

You are attempting to hit 100+ FPS. That is not sustainable by a CPU in many games, no CPU. You see the CPU tests in the latest games? They always show drops to 60 or lower, with average FPS sometimes over double their minimums. These are with the fastest CPU's out there.

 

[bishopi5]

any game that isn't optimiZed for AMD and has had a few decent driver updates (Not a brand new game) will love having 3 cards instead of 2 at that resolution.

 

[Alexkaneaster]

Thanks for the help everyone. I'll stick with the 3 cards, wait for my higher resolution monitor, and see what happens.

 

[unknownofprob]

might as well, let us know on any updates!