Large performance hit enabling AA (HD 2600)

Has anyone else with an HD 2600 noticed a large drop in FPS when enabling any level of anti-aliasing? On the source stress test I go from about 125 FPS (1280x800, everything maxed) at 0xAA/8xAF to about 67 FPS at 2xAA/8xAF. Switching to 4xAA actually netted me a few more FPS (around 73), which is pretty odd. Anyone else experienced this sort of thing?

 

yes its very common..

we all get the same results, maybe due to the 128 bit bus.

 

Anti-aliasing does cause a performance hit, but either way, you're still over the 60FPS barrier - and I doubt that your laptop's screen can display a higher frame rate.

It's probably the method of antialiasing used that caused the weird 6FPS drop. Unless someone can help you, look at it this way: Free 4xAA.

 

It's not due to the bus. People with 8600M GT's can use AA just fine. It's a known problem with ATi's 2000 series.

 

While that's probably true, enabling AA just gives me an overall much less fluid gaming experience (tested with CS:S and WoW)

This is what I was afraid of. Although I'm still running the video drivers that came installed on the laptop. Do you think upgrading to the latest drivers straight from ATI would help any?

 

It's always good to keep your drivers up to date. Although, the newest driver isn't always the best. Just test out some drivers, and see which one yields the best results.

 

Updating the drivers might help, but as mentioned before, the Radeon HD 2000 and 3000 series have busted ROPs and do their anti-aliasing in the shaders, incurring a massive performance hit.

 

yea what he said..I own a hd2600 gddr3 and it sucks if u wanna play max settings with aa..even with my 33fps config i get about 10fps less with only 2x aa enabled..

 

Actually, ATI has historically always lagged behind when it comes to AA, even back to the Rage 128 / Pro / Radeon 9700 days.

Now you know why 3DMark default testing is AA off, and why I questioned in another thread, that firingsquad.com link (4xAA and 8xAA used in their testing, besides the fact that they are a serious unknown).


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It's a combination of the two. The way aa is implemented in the 2xxx series (and 3xxx) and the restrictive memory bus.

I could run at 19x12 with no problem in css on my old 1720 but as soon as I applied AA it gave up, boosting the memory clocks resulted in a noticeable gain though.

The 97/800 didn't lag behind the nvidia FX series, in fact ati dominated that era.
The 48xx series does really well when it comes to AA as well, matching or beating the gt200 at higher resolutions.

 

Yes, this has been discussed before. AA is one of the weaknesses of the HD 2000 series of GPUs.

But I agree with 3NZO on ATi's AA capabilities: it's not a trait of ATi to be weak at AA.