Strange Performance from my HD 6870?

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elsnerj

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So, I just bought Battlefield 3 and began tweaking settings.

My setup is an i7-860 (2.8Ghz) core, one Sapphire HD 6870 (OC ~10%) and 8GB of DDR3 RAM.

At the following settings, I get these frame rates (checked in the same spot/direction):

1920 x 1080 - Everything Ultra (with no deferred AA) - 45 FPS
1920 x 1080 - Everything Low (with no deferred AA) - 48 FPS
640 x 480 - Everything Ultra (with no deferred AA) - 120 FPS

The fact that the FPS increases on a lower resolution tells me this isnt a processor bottleneck.
So, why do I see no difference in performance between Low and Ultra settings for shadows, textures, etc?
 
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The same thing happens to me, only changing resolution and amount of anti aliasing changes the FPS. I just play at 1280x720 with AA, it doesn't look as good as 1920x1080 but the performance is a lot better.

r_00n

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The same thing happens to me, only changing resolution and amount of anti aliasing changes the FPS. I just play at 1280x720 with AA, it doesn't look as good as 1920x1080 but the performance is a lot better.
 
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elsnerj

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Adding AA absolutely drops FPS, turning on Deferred AA at 1920 x 1080 drops my FPS to ~15 regardless of settings.

What's curious to me is that the detail levels of shadows, terrain, effects, etc. seem to have no impact on the card at all. Only AA (which I have to leave off) and resolution seem to change how strained the card is. I've never encountered this in other games, or at least not as extremely (low vs ultra shadows may only change FPS by 10 in Skyrim for example but in BF3 it literally changes nothing.)
 

elsnerj

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Do you also have an HD 6870 or is this a game-related phenomenon? I can see the difference in shadows and etc when I change settings but no changes in FPS. Weird.
 

jjtober1

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Interesting, but I did watch a comparison when BF3 came out of the different settings, and the difference between low to high visually isn't as great as other games. Low settings still looked awfully nice to me, although I didn't actually try them myself. You could install MSI afterburner, and enable the overlay that shows your GPU utilization, and make sure it's at 99% when you compare both settings.
 

elsnerj

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I was actually using Afterburner to find these FPS! I'll play around with it a bit more. I also noticed that visually Low-Ultra was nowhere near as big a difference as most games' relative extremes, probably to ensure everyone playing online has equality. I wouldn't have been shocked if the difference provided by Low-Ultra was only 15FPS or so, but the 2ish (if any) FPS difference I am seeing completely stumps me.

On another (somewhat related) topic:

I run Skyrim on Ultra (No AA) at ~50 FPS in a certain spot.
It runs on Ultra (4x AA) at ~45 FPS. Almost no difference.

Yet on Battlefield 3, enabling ANY (deferred, not post) AA causes a drop of some 20FPS or more. Why the heck is it so much more stressful on the card in BF3 game?

 
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