EVE Performance Issues (looking for video card suggestions)

So I went ahead and pulled the trigger on buying two evga GTX980 superclocked gpu's tonight. I also ordered two more of the Dell UltraSharp 27 PremierColor Monitor - U2713H because I got the first one and the picture quality is amazing and I didn't think I would notice the much lower response time than my old monitors but I probably averaged 7/1 kd ratio in cs:go tonight which isnt unusual for a game or two .. but across 6 games I'm starting to think the monitor has something to do with it.

I heard someone say something before about if you run different gpu's in the same system it will affect performance of both gpu's and that you should only run the same model cards. Is there any truth to that? I was planning to run two monitors off the 980's in sli and the third off my gtx680. Now that I've seen the screen resolution I'm confident everything I will need in my dashboards can easily fit between two screens.

I should have everything by this weekend so i'll be able to test it out and report back the results.

So after a lot of testing with the new system here is the useful info:

11 accounts - two at max quality settings the others optimized for performance.

Roughtly 25% CPU used when the fleet is idle
32% of 32GB of ram used
2.6GB vmem used.

A single GTX980 will run everything @ 60FPS @ 2560x1440 resolution with no problem.

Having two cards exposes a bug in windows 8.1 where the monitor identifiers are not tagged to the correct monitors and this made videofx stuff run across them both for horrible performance. I say horrible but where I was getitng 2FPS on the old pc like this the new one gets 45FPS and is easily playable. So even though I bought 2 of them I'm only using one at the moment. I'll worry about those details later and try not to think about the fact that I dropped an extra $620 on a card that i'm not using at the moment lol.

I've got more isboxer related questions but i'll throw them in a new thread. Thanks everyone for your input on this thread. It was definitely helpful in understanding the underlying mechanics.

[MiRai]

Having two cards exposes a bug in windows 8.1 where the monitor identifiers are not tagged to the correct monitors and this made videofx stuff run across them both for horrible performance.

Is this documented somewhere on a Windows forum? I can't say that I've ever heard of this before, but if you have any sort of DPI/UI scaling enabled in Windows (Control Panel > Display > 100%) then it's going to cause issues; and if your Window Layout is configured incorrectly it could also cause problems.

There was no scaling and I even tried to set the option to force one scaling level on all displays. I don't have a bug number for the issue but here is what happens.

I have 3 Monitors.

When identified on the screen they show left to right as 1, 2, 3. Now when you align them in that order you discover that 2 is actually 3 because your windows and mouse movement are out of place. Even when placed in the right order on the screen they still were wrong (the wallpaper didn't line up, but the mouse movements now did). I have a 7680x1440 wallpaper and no matter what order I put the screens in I could not get them lined up to make the wallpaper sections display in the right order. Taking the other 980 out of the system fixed this.

I thought about moving back to windows 7, but got lazy since I have everything working the way I want it to I'm probably just going to spend some time enjoying the game and later on come back to this issue and screw with it.