Originally Posted by Masked
Your vram on the 590 is limited to 1.5gb/core...period.
It's not 3gb per core...It's 1.5gb per core.
If you run 1 monitor, 1 single monitor, you will get ultra results because you're basically SLI'ing 2 OC'd 570's.
If you're running in 3 monitors, you will run out of ram and the game will putter out.
People that run 3 monitors typically have 580 3gbs in SLI because that's truly, 3gb/core instead of your setup which is 1.5gb/core.
Actually, a 590 is two underclocked 580's in SLI, not two OC'd 570's
Originally Posted by Masked
The issue is that stereoscopic isn't enabled so, when he tries to run 3 monitors, he's running 1 extended which, is what I've been trying point out a couple times.
3D for this game is NOT available...And won't be for a while.
You're not making sense here I'm afraid. The supposition is that he's running out of vram because he's running a very large resolution ... which is in turn caused by using 3 monitors. 3D, or lack thereof, doesn't even enter into this equation. And in fact, 3D doesn't affect vram usage at all.
Originally Posted by criminal
There is not enough VRAM to supply the GPU's what they need. When you SLI, you share the VRAM among all cards. Since you are basically running four cards SLI'd, they are all sharing 1.5GB.
There's no 'sharing' the vram between cards in SLI. In fact, it does the opposite of 'sharing' the vram. If you COULD 'share' vram, then you actually would get an 'additive' scenario in terms of memory capacity w/cards in SLI. The fact that memory capacity isn't additive shows that there's no vram sharing, basically.
It's not a 'practical' solution to share vram between cores, because sharing vram would involve movement of data across the PCI-Ex bus from the memory bank on one card the core of the other. This bus is like an order of magnitude slower than the direct connection between GPU core and vram upon each individual card, and hence, such movement would more than destroy any perf benefit added by running SLI.
Shared vram would also create concurrency issues that, in order to solve, would require very elaborate and expensive hardware to be present on every GPU sold, regardless of whether the card was meant to be used in SLI or not. Neither AMD or nVidia are ever likely to decide such a solution makes sense. It's far simpler and cheaper to simply add memory to each card in order to increase capacity.
SO ... whether you're dealing with multiple physical cards in SLI, or a single PCB/dual GPU card like a 590, each gpu core has it's own attached 'memory bank', in this case, each with 1.5GB of capacity. And each GPU 'speaks' ONLY to it's own memory bank. Each card is responsible for creating entire frames, and they do so in an alternating fashion (what's known as AFR or Alternate Frame Rendering).
What it boils down to is that in SLI (or multi-gpu/single pcb) each GPU has to have an exact COPY of all the same data available in it's memory bank that the other cards in the set have. 1 x 580, or 2 x 580, or 4 x 580 ... all these setups have the same total memory capacity, because when you run 2 x 580, while you have 2 x 1.5GB of physical memory, you also have twice as much data that must be stored.
It's very much like the way HD capacity works in RAID-1 (mirrored) mode.
Originally Posted by Opiuz
I have been reading up on the issue and understand it completely, it is actually quite unfortunate that the Vram is the issue with so much punch under the bonnet she got no juice to run on properly.
in hind site, if i had known this from the beginning i probably would have not baught the GTX590's which for a lack of a better work was frikken expensive
so im going to be stuck with the current 40fps, which is playable for the time being until the new gen cards come out which should hopefully have 3Gig+ Vram, and hopefully still work on my Z68 chipset Mobo
would in your honest opinion recommend replacing the two GTX590's with two GTX580's, and then would this allow 60 fps with the eventual sterioscopic 3D
also with MW3 coming out, do you think this would also be a problem with that game coming out, or do we need to wait for release date to see.
thanks again for all your help.
Yeah, you should've asked here on OCN before buying two 590's
It's really a pretty terrible setup overall I'm sorry to say (unless all you care about is 3dMark scores) ... that's way too much GPU power to only have 1.5GB of available vram capacity.
I would sell them and get 2 x GTX580 3GB. That should be plenty enough powah for anything in 2d at any res unless you have 3 x 30" monitors. You may decide you want a third once you go to 3d Surround, but I'd start out w/two and see how it does and decide then whether you need more juice.Edited by brettjv - 10/28/11 at 2:03pm