AMD CrossFire Performance

Update, 10/24: Turns out there's a "hidden" setting in the configuration file that needs to be manually enabled for Mantle SFR rendering on CrossFire setups to work. Go to your configuration file (%homepath%\Documents\my games\Sid Meier's Civilization Beyond Earth\GraphicsSettings.ini) and change the one line to say "Enable MGPU=1". This will allow Mantle SFR to work properly. I had to retest CrossFire performance, and the updated results are below, with a more detailed explanation posted in a separate article.

Last but not least we have some early results for CrossFire performance. With the appropriate tweak to the configuration file, Mantle CrossFire support adds an interesting wrinkle to the mix. Regular CrossFire still works as usual, but minimum frame rates take a hit relative to single GPUs even while average framerates improve. Here are a couple graphs showing scaling of performance as we move through the various settings. I've included both single GPU and CrossFire results for the R9 280 and R9 290X, both with and without Mantle:

CrossFire 290X ends up pushing past the 60FPS barrier, even at 4K with 4xMSAA, so that's quite a feat. Except, minimum frame rates take a hit and go from 32FPS with a single 290X to 20FPS with CrossFire 290X. Enabling Mantle changes the story quite a bit; the CrossFire Mantle configuration can't quite push past 60FPS, but at 56FPS it's at least close and the minimum frame rate of 37FPS is better than both the single GPU and single GPU with Mantle figures.

We can also see quite nicely in this graph that the CPU bottleneck at High and Ultra settings is around 110-120FPS, even with a 4.1GHz Core i7-4770K, while our minimum FPS bottleneck is even lower: 65FPS for CrossFire Mantle and 49FPS with a single 290X (without Mantle).

As for the R9 280 CF configuration, the two Tahiti GPUs (without Mantle) come just short of matching the performance of a single R9 290X Hawaii card. Mantle again improves minimum frame rates, but the gap between R9 290X Mantle and R9 280 CF Mantle grows. This is one more reason why we generally prefer single GPU configurations, at least up to the point where you have the fastest GPU you can buy.

Civilization: Beyond Earth Minimum Frame Rates Civilization: Beyond Earth Testing Notes
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  • RagingCain - Thursday, October 30, 2014 - link

    I updated CIV: BE FTA to v0.0.2, there was a minor bug on low FPS users, I also added graphing capabilities.
  • RagingCain - Thursday, October 30, 2014 - link

    Direct Link: http://www.bytemedev.com/civbefta/
  • JlHADJOE - Friday, October 24, 2014 - link

    Kinda funny to be going back to SFR now. IIRC it was how the original SLI worked back during the 3Dfx days.
  • JarredWalton - Friday, October 24, 2014 - link

    Yup, though the splitting was Scan-Line Interleave (each GPU did every other line), which is messy if you want to do things like AA. Other SFR methods include vertical and horizontal splits, which can result in unequal workloads, or breaking the scene up into tiles. I believe CivBE is using tiles for SFR; more complex in some ways, but overall a good way to improve performance.
  • just4U - Friday, October 24, 2014 - link

    You having some fun with the game while you test it Jarred? lol.. I am just downloading it right now.. OH it's finished.. time to play!
  • zoomzoomzealot - Friday, October 24, 2014 - link

    Does Mantle have any impact on thermal output of the video card? I would imagine extra processing means extra heat. Could this be an issue for people who have already OC'd their GPU?
  • zoomzoomzealot - Friday, October 24, 2014 - link

    Another piece of that question would be power usage increases?
  • jaredjeya - Friday, October 24, 2014 - link

    My name and middle names are Jared Anand. This is an article on Anand Tech by a guy called Jar(r)ed. perfect.
  • Concillian - Friday, October 24, 2014 - link

    Any plans on a "CPU vs. time between turns" benchmark (and/or a mantle / no mantle vs. time between turns)? These kinds of games I don't care too much about visuals, but I do care about time between turns.
  • liquid_mage - Sunday, November 2, 2014 - link

    I'm a little puzzled by the benchmark. I have an I7-4770K, 8gb ram, and a Radeon 5870. When I play at 1080p with High settings with 2X MSAA, I get 55-65 fps. This is general game play not the benchmark, but to me is makes the benchmark a bit misleading.

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