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The Myths Of Graphics Card Performance: Debunked, Part 1

More Graphics Memory Measurements

Io Interactive's Glacier 2 engine, which powers Hitman: Absolution, is memory-hungry, second only (in our tests) to the Warscape engine from Creative Assembly (Total War: Rome II) when the highest-quality presets are taken into account.

In Hitman: Absolution, a 1 GB card is not sufficient for playing at the game’s Ultra Quality level at 1080p. A 2 GB card does allow you to set 4xAA at 1080p, or to play without MSAA at 2160p.

To enable 8xMSAA at 1080p you need a 3 GB card, and nothing short of a 6 GB Titan supports 8xMSAA at 2160p.

Once again, enabling FXAA uses no additional memory.

Note: Ungine’s latest benchmark, Valley 1.0, does not support MLAA/FXAA directly. Thus, the results you see represent memory usage when MLAA/FXAA is force-enabled in CCC/NVCP.

The data shows us that Valley runs fine on a 2 GB card at 1080p (at least as far as memory use goes). You can even use a 1 GB card with 4xMSAA enabled, which is not the case for most games. At 2160p, however, the benchmark will only run properly on a 2 GB card so long as you don't turn on AA, or use a post-processing effect instead. The 2 GB ceiling gets hit with 4xMSAA turned on.

Ultra HD with 8xMSAA enabled gobbles up over 3 GB of graphics memory, which means this benchmark will only run properly at that preset using Nvidia's GeForce GTX Titan or one of AMD's 4 GB Hawaii-based boards.

Total War: Rome II uses an updated Warscape engine from Creative Assembly. It doesn't support SLI at the moment (CrossFire does work, however). It also doesn't support any form of MSAA. The only form of anti-aliasing that works is AMD's proprietary MLAA, which is a post-processing technique like SMAA and FXAA.

One notable feature of this engine is its ability to auto-downgrade image quality based on available video memory. That's a good way to keep the game playable with minimal end-user involvement. But a lack of SLI support cripples the title on Nvidia cards at 3840x2160. At least for now, you'll want to play on an AMD board if 4K is your resolution of choice.

With MLAA disabled, Total War: Rome II’s built-in “forest” benchmark at the Extreme preset uses 1848 MB of graphics memory. The GeForce GTX 690’s 2 GB limit is exceeded with MLAA enabled at 2160p. At 1920x1080, memory use is in the 1400 MB range.

Note the surprising factor of running a supposedly AMD-only technology (MLAA) on Nvidia hardware. As both FXAA and MLAA are post-processing-based techniques, there is no technical reason why they won't run on interchangeable hardware. Creative Assembly is either switching behind-the-scenes to FXAA (despite what the configuration file says), or AMD's marketing department hasn't picked up on the fact above.

You need at least a 2 GB card to play Total War: Rome II at its Extreme quality preset at 1080p, and likely a CrossFire array with 3 GB+ to play smoothly at 2160p. If you only have a 1 GB card, the game might still be playable at 1080p, but you'll have to make some quality compromises.

What happens when graphics memory is completely consumed? The short answer is that graphics data starts getting swapped to system memory over the PCI Express bus. Practically, this means performance slows dramatically, particularly when textures are being loaded. You don't want this to happen. It'll make any game unplayable due to massive stuttering.

So, how much graphics memory do I need?

If you own a 1 GB card and a 1080p display, there's probably no need to upgrade right this very moment. A 2 GB card would let you turn on more demanding AA settings in most games though, so consider that a minimum benchmark if you're planning a new purchase and want to enjoy the latest titles at 1920x1080.

As you scale up to 1440p, 1600p, 2160p or multi-monitor configurations, start thinking beyond 2 GB if you also want to use MSAA. Three gigabytes becomes a better target (or multiple 3 GB+ cards in SLI/CrossFire).

Of course, as I mentioned, balance is critical across the board. An underpowered GPU outfitted with 4 GB of GDDR5 memory (rather than 2 GB) isn't going to automatically be playable at high resolutions just because it's complemented by the right amount of memory. And that's why, when we review graphics cards, we test multiple games, resolutions, and detail settings. It takes fleshing out a card's bottlenecks before smart recommendations can be made.