Lord Maldoror
Fairlight Corp Rooks and Kings
494
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Posted - 2013.05.29 20:41:00 -
[1] - Quote
Everyone's needs in Eve are different; depending what you do, your requirements may vary from a pocket calculator to a top end gaming rig.
A few things about Vram and multi-GPU setups, however.
1) Do you play Fullscreen or Fixed Window?
SLI (the Nvidia version of multi-GPU) evolves through different profiles, as does Crossfire (the ATI Version). However, traditionally Alternate Frame Rendering ('AFR' - the method of multi-GPU used by both manufacturers in Eve) is better optimised for Fullscreen than for Fixed window. For example, let's have a look at the GPU load in two scenarios:
Fullscreen / Max Details / Vsync off ('Interval Immediate):
Geforce Titan #1 @1.1Ghz = 87% load Geforce Titan #2 @1.1Ghz = 87% load
The framerate at this random moment is around 670fps (obviously depends on scene) and both cards are loaded equally, which is how things should be in SLI. Both Titans are running their full (overclocked) clockspeed. The reason the cards are not on 99% load is that the CPU can't keep up supplying them with frames to render flat out (two titans can someitmes cpu bottleneck even a 3960X @ close to 5ghz).
Now let's switch to Fixed window:
Fixed Window / Max Details / Vsync off ('Interval Immediate):
Geforce Titan #1 @1.1Ghz = 63% load Geforce Titan #2 @1.1Ghz = 99% load
Both cards retain their 'full' clockspeed (sometimes in the past SLI has downclocked one card using fixed window) but the GPU load is no longer evenly split, which drops the fps by nearly 200 frames a second to around 490fps (admittedly still very high).
What conclusion can you draw from this example? SLI works but if you're a multiboxer, you're likely to be using Fixed Window a lot, where SLI, although working, is not perfectly optimised. Different cards in the range will vary and different drivers will too. But it's usually better to buy the best card you can afford and then add a second if and when you can, rather than to rely on multi-GPU drivers.
Which brings us to the next point, Video Ram.
2) What's the deal with Video Ram and Eve?
The more clients you have open, whether fullscreen or fixed window, the more video ram you will use. High settings will considerably inflate the amount required. As a ballpark figure, a max settings client can easily use 1gb of video ram @1080p.
Higher resolutions (or the use of tools like Nvidia Inspector to force more extreme modes of anti-aliasing) will vastly increase the amount of video ram required.
A shot like this at 4K resolution (3840x2160) uses around 2.5Gb of video ram. The most I've peaked at with 4K resolution is 3.7Gb of video ram (a Titan has 6gb video ram; a 780 has 3gb, which would be bottlenecked by this).
What happens if you exceed the video ram you have? Nothing as dramatic as you think - you'll see 'hitching' and stuttering but the card(s) will try and cache the memory and swap it in and out between clients. The more you go over the video ram, the more pronounced the effect becomes.
On multi gpu setups the Framebuffer is copied. Three 6Gb titans do not mean 18Gb of video ram - the game clients can still only use 6gb. This is another reason why a single fast card with more video ram will be better than two midrange cards with less.
I have to get back to game but if there is a demand for it, I can probably sometime make a guide of different top end video cards and their respective performance in fleet combat, along with internal benchmarks we have for loading grid fast on triage setups (regarding ram, cpu, ssd, etc.).
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