GeForce GTX260+ vs Radeon 4850 Part 2: Image Quality
8x Multi-Sampling
Let’s start with 8xMSAA. More reviewers are starting to use this setting and this is good to see as I’m a strong proponent of it. In addition to providing a visible benefit over 4xAA, it also represents a major advancement in anti-aliasing in consumer space since the Radeon 9700 Pro debuted sparse grid 6xAA back in 2002.
Starting with the theory, here are the sample grids for both cards running 8xMSAA. Note that 8xMSAA corresponds to ATi’s 8x Box and nVidia’s 8xQ setting.
We’re interested in the blue dots here, which represent the locations of the multi-samples in the pixel’s area. Both cards have eight of them arranged in a sparse grid, hence theoretically both cards should have similar image quality, though one could argue that nVidia’s samples are a bit more evenly distributed. Regardless, the workload performed by each vendor should be identical.
Theoretical grids are all well and good, but what does it look like in actual games?
For the screenshots I’ve picked a scene from Doom 3 (a title where the 4850 handily beat the 260+ with 8xAA), and I’ve zoomed to a section that contains angled lines and shadowing.
260+ (4xAA)
260+ (8xQ)
4850 (8xAA)
Pay attention to the three areas labeled with the white arrows in the 4xAA picture. Compared to the reference 4xAA image taken on the 260+, you can clearly see that 8xAA is smoother on both cards in all three sections. You could even argue that the 4850 is a bit better than the 260+, especially with the smoother shadow edge in section (3).
From the screenshots, we can conclude that 4850 is not only applying 8xMSAA when requested, but it also looks a little better than the 260+ in this particular instance. So then, the issue of slow 8xMSAA performance is squarely a problem with nVidia and is not related to ATi doing something inferior or wrong; quite the opposite actually in this case.
It’s also worth mentioning that based on my Catalyst 9.1 review, the 4850 is now basically tied with the 260+ at 1920×1440 with 8xMSAA in Quake Wars due to a driver performance gain. Again, this simply shouldn’t be happening based on the cards’ relative specs.
nVidia needs to fix whatever is causing this abysmal 8xMSAA performance in OpenGL.
This is the best image quality comparison I’ve seen regarding the 4800s and GTX 200s. As always, great job BFG, and thanks for all of the hard work.
Damn, i have to agree. i was lucky to get a preview of this review and i learned a lot from it. BFG10K has been working on and polishing this review for quite some time and his hard work and effort really shows in a deep but very clearly understandable article. He does not waste a single word yet covers what he intends expertly.
Thanks for your support everyone. It’s the readers like you that make it all worthwhile.
I Used to be a die hard nvidia fan – loved my BFG 7950GT,Had a truly fabulous Zotac 8800GT AMP, But my last graphics upgrade has been my first to cross over to ATI and the HD4850. I now have 2 in crossfire (mainly because nvidia motherboards are quite frankly terrible ! Having been unfortunate enough to own a couple i include the Striker 2 extreme in that). I have friends still scared to try anything but NVIDIA or Infact made by BFG -(Great cards,incredible warranty – but have you ever had a gfx card for more than a couple of years ?)- They own 260’s and 280’s but i wouldn’t swap the ATI’s because the gaming performance and picture quality is i’m afraid to dissapoint you – BETTER WITH ATI 4800 SERIES GRAPHICS CARDS. These things happen AMD were great and overclocked for england ,Intel topped them with the core 2’s, Nvidia 8 series were great, GTX200 series came out too expensive and ATI struck gold with the RV770 chipset , swings and roundabouts gentlemen , What counts above all else is FPS per £/$ and that means ATI 4800 .
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