Widescreen Gaming Forum

This is a nasty problem, actually.

The GTX460 is the only Fermi based card that really has enough VRAM to cope with the demands of AA enabled Surround, but it's not as powerful as a GTX470 or 480 in terms of raw processing power.

This results in a tradeoff - more VRAM, or more grunt?

Honestly, I'd try running those panels with AA off, and see how it goes. If it really, really needs it... try dropping the res.

The only card I know of that actually does everything I want right now in terms of Surround (lots of VRAM, more power than a 460) is a Quadro card that is basically a cross between a 470 and 480 (470 shader count, 480 memory bus) paired with 6GB!!! of GDDR5. It comes with a nasty price tag of £4200, too. So isn't really a feasible proposition. ;)

I realise this probably won't help you much - if you were going to game at 5760x1200 or such, I'd say go dual 2GB GTX460s. As you've got 7680x1440 to push instead, I don't think you can afford to lose the extra power of the GTX470s. :(

scheffchen,

Check out the benchmarks in this review: http://www.hardocp.com/article/2010/08/16/sli_cfx_pcie_bandwidth_perf_x16x16_vs_x16x8.

Among the benchmarks, they're testing at 3x 1920x1200 resolution a 5870 at 1gb and 2gb of ram, with very little difference realized. It could be a 5870 limitation, or it could be the different cross-section of games they tested weren't as demanding on vram. All of their testing focuses on keeping the framerate playable though, they may not be cranking things up enough to tax the memory.

Paradigm has found at least one game that can demand enough vram to reaaaaallly clearly make a difference, though. There is more to be learned here.

Paradigm, if your full review is now posted I haven't been able to find it, a link would be greatly appreciated.

Hello and good morning everybody,

first thank you for the quick answers so far.

I agree that the power of a gtx470 in comparison to the 460 can be critical.
The charts showed, that with the 1gb cards there was a short drop in frame rate to 9fps. When speaking about the flight sims (FSX, Lock on 2, Black Shark) these use older engines that rely more on processor power than on high-res textures. Conclusion may be, that for actual games with Hires graphics, I may have to lower the resolution while on the sims it could work out.

Ratfusion, thanks for the link to that review, it seems like the performance is very game dependant which underlines my thesis.

Maybe next year there will be GFX-cards available with a vram of >2gb for a reasonable price.
I still have to think whether to buy the monitors or not but I tend to to so.

Regards
Boris

As HardOCP uses "best playable settings" the results I obtained can't really be directly compared - I was after trying out a distinct set of perhaps-over-the-top settings at Surround resolutions and seeing whether it made cards choke.

I expect I could probably make GTX480 SLI choke with some of the settings used, never mind the mind-range cards. ;)

There are graphics cards with 2GB of VRAM available for a reasonable price... they're the GTX460. :D I just think that Metro 2033 in particular is going to be utterly unplayable with the details turned up, even on 2GB cards, because of the sheer power needed for that game.

some more info here:

http://www.hardocp.com/article/2010/08/17/geforce_gtx_460_sli_vs_radeon_hd_5870_cfx_5760

Benches 2x gtx460 against 2x hd5870. And mentions a little about AA and the 1GB Frame buffer.

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Thanks for posting this up Paradigm. I really had no idea how much of an impact VRAM had on performance in surround until I saw this. It does raise one question however, you mention that after a card maxes out it's VRAM it goes to normal RAM, would acquiring more RAM help increase framerates when this occurs in games, or is it the offloading of the VRAM to the RAM itself what causes the massive framerate drops? If so, would it also be possible to perhaps dedicate an amount of RAM to VRAM, permanently - to avoid the system crapping out when it has to offload to RAM?

I ask this because I had a rather odd issue awhile back that I never sorted out.. I had purchased a new processor (went from a dual core to a quad core), and upon booting up I lost about 750mb RAM. In BIOS it recognized all 4 Gigs of RAM, but only 3.25GB we're "Usable". I checked for bent pins, dust, re-seating ram, updated bios, troubleshooted for days, never figured out the problem. All my games still worked fine, no blue screens, so I ended up going on my way, decided to quit before I just made things worse. I went to update my windows experience index and when I did I found that windows was indicating my Video Card had almost 2.5gb of VRAM, accounting for my mysteriously lost RAM. This problem went away when I got a new motherboard, and I haven't been able to replicate it, not that I tried. Odd that I'm finding myself now trying to replicate this problem that drove me mad :P.

Sorry if I'm mucking up your thread here with my silly questions >_> Just curious about the wonderful inner-workings of VRAM/System RAM.

you need a 64 bit OS to address more than ~3.25GB system ram

_________________
P8Z68-V Pro | 2600K | HR02 | HD5850 | 2x4GB Vengeance LP | 128GB M4 + 6TB | X-Fi > HD595 | AX850 | Tai Chi | PB278Q | G110 + Deathadder 2013
P8Z77-V | 3570K | Mugen 2 | HD5850 | 2x4GB Vengeance LP | 500GB | X-750 | Fractal R3 | U2212HM | G110 + G400
P8H77-I | G860 | 4650 | 2x2GB XMS | 320GB | CX500 | Prodigy | T22B350EW | MX518
DC3217IYE | 1x4GB Vengeance | 64GB M4 | TX-42VT20E

I was running Windows 7 Ultimate 64-bit at the time, and I still am; if it matters. :P I'm well aware of all of that. I had full use of my 4GB RAM before I installed the new processor. But that wasn't really the point of my little anecdote, the problem went away with my new motherboard (perhaps a damaged, mobo? I dunno; Still using the same RAM.)

Right, I'll try to answer all your questions, but in a random sort of way...

The reason you had RAM vanish when you swapped cards was it was probably borrowing system RAM for the GPU ("Hypermemory" was what ATi called it, "TurboCache" nVidia).

Acquiring more system RAM might help to some extent. Bear in mind that system RAM has, what, 6-8GB/s of bandwidth available? Most of the high-end video cards are looking at 100GB/s and upwards. Big, big difference there. Also, when running in SLI, I suspect it chews up double the system RAM expected (it needs to mirror data for each GPU, yes?) so unless you were thinking of popping in, say, 12GB... I think the change would be minimal. Also, it would still go swap to pagefile (even slower than system RAM, from 6GB/s to 150MB/s max...) which is what I think Aliens vs. Predator was doing for me when testing at the really ultra settings.

Dedicating system RAM to VRAM is just a waste of time IMO. It's so slow that it's not worth it. The use of system RAM as VRAM by integrated chipsets is one of the reasons why they suck, after all.

You got PM.

Paradigm did your full review ever get posted? I can't seem to find it.