Huge fps drop when using dual screens?

I have followed the directions in the forums for placing my mfcd's on my second monitor. However my fps drops from around 60 to a slideshow. I have the mfcd's set to the lowest resolution in the options menu but still very little improvement. Obviously dual screen gaming requires more horsepower but I didn't expect quite this amount of impact.

I have an i7 920 overclocked to 3.7, 6 gigs of ram and sli gtx 460s with 768 mb of ram. My main screen is 1920x1200 and my second is 1680-1050.

So you can imagine my questions:

What might be bottlenecking my system? What software might I run to see what part is the weak link? I am thinking the video ram is to little but don't know how to check how much warthog is using.

Does having the mfcd's on the second monitor tax the system more than showing dual cockpit views?

A somewhat related question - can I put a view on the second monitor like the chase camera or missile camera? Darn it would be so cool if I could keep the cockpit view at the same time as following the Maverick or bombs!

Not sure but if you use 2 monitors you must be in windowed mode then?

crossfire or SLI is supported only in fullscreenmode.

I can be wrong but first thing what i figured.

You can try setting up SoftTH to take advantage of Fullscreen.

What might be bottlenecking my system? What software might I run to see what part is the weak link? I am thinking the video ram is to little but don't know how to check how much warthog is using.

 

To see what the video card is doing.

GPU-Z

VRAM is definately at least part of the problem, IMHO.

Not sure but if you use 2 monitors you must be in windowed mode then?

Incorrect. Some games do have trouble with this (like Tropico 3 which plain won't start), but I run DCS products at will in fullscreen even with a second screen active. Given though, this "at will" is rather seldom since I usually prefer window or "fake-full" for easier task-switching, but it does work.

Of course, how this equation ends up affected by SLI applications is a different question. One thing I'd definitely worry about with the 460 though is that it is extremely easy to run out of vRAM when operating in dual-screen modes, which will come at a serious performance cost. Note here that having two cards with 768mb of vRAM in SLI still means you have 768mb vRAM - not 1.5GB.

Basically, the vRAM is small, and the memory bus on those cards is also pretty slow.

That's also incorrect! (I Think you simply misunderstood his question. - He wants full-screen on both monitors at the same time)

Up to now I never saw a NVIDIA or AMD/ATI GPU/Driver on the consumer level that is able to handle a 1920x1080 together with a 1680x1050 as a full-screen DX environment out of the box.

Well, unless you use SoftTH.

(here are the corresponding links to MTFDarkEagles answer: BS and SoftTh:Black Shark Twin monitor SoftTH and DCS in general: http://forums.eagle.ru/showthread.php?t=71710 )

Ah, in that case yes, I misunderstood the question. :)

The situation I use is game in fullscreen on one monitor, the other screen showing other things (anything from video to just displaying chatbox and mail so I can react when I'm needed).

I would however still suspect there might be problems with the vRAM, but following your suggestions will hopefully help if replacing the video cards is not an option (or just highly preferably avoided).

Agreed vRam maybe is not enough. But because he must play windowed mode there is no use at other gpu at all because SLI is working full screen games only.

I have been played A-10 with 2 monitor with my old ATI 5970 and it was not slideshow, memory 5970 has 1gig.

Thanks for the responses and repped!

It is correct that I want both screens displaying game generated info - one for cockpit and one for mfcd's.

If I were to use the ipad solutions mentioned on this board to show the mfcd's does this create extra challenges for the video card or is the processing load offloaded onto the ipad?

Also, was anyone sure about my last question - Can the second screen be used to show bomb or missile follow view?

 

If I were to use the ipad solutions mentioned on this board to show the mfcd's does this create extra challenges for the video card or is the processing load offloaded onto the ipad?

;) There is nothing like a free lunch in the whole universe!

The Ipad is agnostic to the compressed image Data it gets/shows...,

- but the data has to be first created by your GPU.

So: you will see a hit in performance.

Also, was anyone sure about my last question - Can the second screen be used to show bomb or missile follow view?

Agreed vRam maybe is not enough. But because he must play windowed mode there is no use at other gpu at all because SLI is working full screen games only.

Except that there is plenty of GPU's that can do what two of those cards do - alone.

(Source: Techreport.com)

Single GPU at 300 US dollars, and performs noticeably better than two 768 460's. (Compare to the 1GB 460's and you'll see the massive effect that shortcoming has. Doesn't get better in lower settings either.)

That's tangential to this discussion though, I guess, but I do think that those cards just have way too little vRAM for multi-screen operation. I'd personally say 1GB is near-required already at a single 1080p screen, with more definitely preferable if you intend to spread a game across more displays.

Regarding iPad display, I would suspect it depends on how the application in question handles that. (I've not tried it myself so I'm not sure.) If it has a hook to get at the MFCD screen data anyway, it might not require extra workload beyond the CPU compressing the data stream - the game already runs those "cameras" so the data should already be rendered; and not rendered twice. But again, not entirely sure how it's implemented.

Nice compact info about cards again!

I want to ad that your current cards also consume more power than a single modern mid-range one- it maybe can easily out weight the costs of a new mid-range over a year.... (at least here in Europe)

Some more tech-talk,

regarding the render of the MFCDs:

The data is already in the GPU - but it has to be "composed" again to match the needed size for the IPad... - even if this may not use a lot GPU time - it eats up V-RAM. ...and further: it has to be transported back to the ram and compressed as stream of images. - this eats up CPU cycles and more ram.

The IPad does know nothing of DX - it only gets a stream of compressed images.

as I said (...and many proved):

There is nothing like a free lunch in the whole universe!

If you are in Windowed Mode, be sure to choose an Aero Theme for Windows. Gives 5-10 more fps.

MFCD's

It must be your vid card (and running in SLI). I have a system very similar to yours and don't get any slowing of f.p.s..... and i run MFCD's and Helios... (http://forums.eagle.ru/showthread.php?t=70880&page=20)