Today's Hard|Forum Post
Today's Hard|Forum Post

NVIDIA Kepler GeForce GTX 680 SLI Video Card Review

We've got two GeForce GTX 680 video cards to test SLI performance against Radeon HD 7970 CrossFireX. Will these less expensive GTX 680 video cards offer a better gameplay experience or choke at high resolutions due to a smaller VRAM footprint? We will prove to you which solution offers better efficiency and performance.

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Battlefield 3

We are using the downloaded version of Battlefield 3 via Origin. This game supports two different antialiasing methods, traditional MSAA via the "Deferred AA" option and shader based FXAA via the "Post AA" option. We evaluate the highest playable gameplay settings and take into account performance and image quality, striving for the best. In that regard, we will use whatever the appropriate AA setting, or combination of AA settings, are best for the video cards being used. Our testing procedure and evaluation of graphics features in BF3 are explained in our Battlefield 3 Gameplay Performance and IQ evaluation. We are using the latest patch for this game.


Highest Playable Settings - Multi-Display Multi-Card

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Battlefield 3 is a great game to test at NV Surround and Eyefinity resolutions, not just because it looks great, but because this game also is a VRAM memory hog in our testing. We've found though that this game uses more VRAM in multiplayer mode, than it does in single player mode. The table and graph above reflect testing in the single player campaign. However, we did do some specific testing in multiplayer that we will talk about below in the next section.

The new GeForce GTX 680 SLI solution did great in BF3 and we had no trouble running at 5760x1200 with the highest ultra settings including HBAO turned on. In addition to that, we found FXAA performed brilliantly and there was performance to spare. We notched the MSAA level up to 2X MSAA on top of FXAA and were surprised to find this setting playable. We were averaging 50 FPS and never dropped below 30 FPS in the single player campaign.

The AMD Radeon HD 7970 CrossFireX solution equally provided a similar gameplay experience. We found that all ultra settings were playable along with HBAO. We found FXAA was playable and on top of that 2X MSAA as well. The average framerate was just slightly higher on 7970 CFX at 53.4 FPS, and the minimum slightly higher as well at 40 FPS.

The aging GTX 580 SLI did not do so well at 5760x1200. We found that we had to disable HBAO and use the lesser SSAO setting, which reduces the quality of ambient shadows in the game. There was no other way though, with HBAO enabled performance was extremely bottlenecked on GTX 580 SLI even with just FXAA. Once we reduced the quality to SSAO, then FXAA only was playable at 5760x1200. Therefore, the new GTX 680 SLI improves upon GTX 580 SLI by allowing HBAO and a higher AA setting, which at this resolution is impressive.

Multiplayer

We performed specific testing in multiplayer on a 64 player server that was fully loaded to test performance and look at VRAM usage. We used MSI Afterburner to display real-time VRAM usage of each GPU and wrote down the maximum capacity the game was using on each solution. To get a consistent look at performance we used the same server, which had a low ping, and the map we tested on was Caspian Border in the Conquest Large game type, we used the same method described in our look at multiplayer performance in BF3. Since this is multiplayer we aimed to keep the average FPS around 60 if we could.

Keep in mind, the memory capacity on GTX 580 SLI is 1.5GB per GPU, and on GTX 680 SLI it is 2GB per GPU and on 7970 CFX it is 3GB per GPU. In SLI and CFX this is not combined, as each GPU must have a copy of the framebuffer, so only the total capacity of one GPU is your max VRAM capacity for SLI and CFX.

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GeForce GTX 680 SLI - Using the highest in-game settings of ultra, along with HBAO and default motion blur, we found that the highest playable setting was FXAA at 5760x1200 on GTX 680 SLI. At 5760x1200 FXAA and the highest in-game settings we were averaging 60-70 FPS, and the lowest framerate we saw was 50 FPS. This setting allowed an incredibly smooth multiplayer experience.

When we tried to turn on 2X MSAA it brought the FPS down to 40 FPS average and at 4X AA the game was completely choppy and unplayable. What you can see from the table is that at FXAA we are already tapping the full potential of the VRAM capacity at 2012 MB, going to 2X or 4X only takes us even higher over the capacity.

Radeon HD 7970 CrossFireX - The memory capacity may seem odd at first, but keep in mind that these results are taken with the game running at 5760x1200 with ultra settings and HBAO enabled. In other words, the highest possible settings capable, which are not actually the highest playable settings on 7970 CFX as you will read below. We wanted to take these memory results at the same settings between all configurations so these would be comparable. Even with just FXAA enabled we are over the VRAM limit, 3541 MB was being used, when the cards only have 3GB per GPU. Increasing to 2X and 4X AA took us to near 5 GB of memory. This game can certainly use what's there, that's for sure. At these memory capacities, the game was not playable at the highest in-game settings on 7970 CFX.

In terms of performance with Radeon HD 7970 CFX we had to lower the ambient occlusion setting of HBAO down to SSAO in order to get smooth enough performance. With GTX 680 SLI we were able to keep ambient occlusion at the higher HBAO mode, but with 7970 CFX the performance wasn't there to give us a smooth gameplay experience with HBAO enabled. We had to disable HBAO and use SSAO instead. We also had to disable motion blur all together. By turning off motion blur and turning the AO quality down to SSAO, performance felt smooth enough to us. However, there are some hardcore players that may still find that not quite smooth enough. In that case, you could disable AO all together, and with that disabled completely it provides a large smoothness increase.

Once we did all that, then it was only playable at FXAA, just the same as GTX 680 SLI. When we increased to 2X and 4X MSAA, performance was choppy and unplayable. Even though 7970 CFX has more memory, and a higher memory bandwidth, that didn't do anything for us here in multiplayer over GTX 680 SLI. While both setups were at FXAA, GTX 680 SLI had the better experience since HBAO was enabled.

GeForce GTX 580 SLI - GeForce GTX 580 SLI was the most bottlenecked in multiplayer. At the highest in-game settings the memory capacity was at its limit with just FXAA, and at 2X AA it just couldn't go any higher. We had so much trouble that at 4X AA the game crashed, and just wouldn't run for us.

As for performance, we had to disable motion blur and disable ambient occlusion completely at 5760x1200, and only use FXAA. At these settings performance was averaging just 50 FPS and the minimum was around 40 FPS. This performance level might not even be fast enough for some hard core players, and in that case the only thing left to do is to lower the quality settings from ultra to high, which will give you the performance you need.

Multiplayer Summary - GTX 680 SLI offered the best multiplayer experience, despite it having less VRAM capacity and memory bandwidth. We were able to run with motion blur enabled and HBAO turned on at 5760x1200 with FXAA and averaged 60-70 FPS. This amount of performance is perfect for multiplayer, and with the highest in-game settings enabled the game looked great at multiplayer. AMD Radeon HD 7970 CrossFireX struggled for performance, even though it had more RAM and memory bandwidth. To get the game to feel smooth enough with enough performance we had to lower ambient occlusion and motion blur. GeForce GTX 680 SLI was the clear winner in multiplayer.


4X MSAA Comparison

Now we are back to the single player part of the game, and looking at 4X MSAA performance at 5760x1200 to see if there is bottlenecking. The GTX 580 SLI configuration was incapable of running at this setting, it crashed on us.

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At 5760x1200 with 4X MSAA and the highest in-game settings Radeon HD 7970 CrossFireX was faster, and had a much better minimum framerate. The average framerate isn't massively different, but you can see how 680 SLI dips below 30 FPS quite a few times, while 7970 CFX does not. The behavior between single player and multiplayer in this game is very different.

FXAA Comparison

Now we can look at performance with FXAA enabled, reducing memory bottlenecks.

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Radeon HD 7970 CFX is slightly faster than 680 SLI, but not very much so. GTX 580 SLI is completely bottlenecked at this setting. Again, the single player result is opposite of multiplayer, where 680 SLI was vastly superior.