ATI Radeon 4800 Series Detailed
Comparing AA Methods
Multisampling is a standard method of anti-aliasing in most consumer graphics hardware for the last few generations. Current AMD and NVIDIA 3D graphics hardware both offer multisampling as their standard method of anti-aliasing. But what exactly does it do for those who don’t know?
In multisampling, each pixel is made up from some number of samples where the number indicates the level of multisampling, usually 2, 4 or 8 samples per pixel, although some earlier AMD hardware also offered 6 samples as an option. In multisampling, each unique sample that makes up a pixel can have its own color and depth value stored (so for 8x multisampling AA the hardware stores up to 8 color and depth samples for each pixel). The vast majority of pixels are fully covered by a single object, and these pixels only require one sample to be stored, making multisampling efficient as a method of saving memory bandwidth - multiple samples are generally only needed at polygon edges or where objects intersect.
The NVIDIA Way
Coverage Sampling AA
This method is offered by NVIDIA on their current hardware. It can be considered to be an extension of multisampling AA, something that gives a kick to consumers. A little more spice. For each pixel in addition to storing the color and depth data for each sample, as in standard multisampling, some additional “coverage samples” are stored. These coverage samples cannot have their own color and depth information, but make use of the color/depth information of the existing multisamples. The coverage samples essentially just give additional information on which regions of the pixel are covered by the existing colors.
Since no additional depth or color values are stored for the coverage samples they require very little storage, allowing CSAA modes to offer an apparently increased number of samples at the same performance as the underlying MSAA mode. A typical CSAA mode might have 4 full samples with color and depth, and an additional 12 coverage samples, theoretically allowing edges to have the apparent quality of a 16 sample mode, but with lower storage requirements.
So…What Did AMD Lead This Time?
AMD’s hardware offers customized filters that are applied when combining the multiple samples to create the final image. When viewing an anti-aliased image the multiple samples in the original image need to be reduced to single samples for viewing. Traditionally this is done using a box filter (a filter that simply averages each of the samples within a pixel).
AMD latest edge technology offers an advanced filter method that uses the shader processing power of the ATI Radeon HD 3800 and ATI Radeon HD 4800 series processors to analyze the multi-sampled image, locate all the edges and apply advanced filtering on these edges. Using this technique can give extremely high anti-aliasing quality, while still using only the same number of samples as the standard multi-sampling mode, aka Edge Detect.
Below is a pictorial description of what each mode offers in terms of quality. Each mode progressively offers a more anti-aliased wire, where the ATI does indeed come out on top.
I think I just gizzed my pants
PCEnthusiast replied on June 24, 2008 9:16 PM:
Hahaha
Officially Awesome = 4800 line
That AA sampling demo is intense. Thanks WiG
Wowwww
venkatezh replied on June 24, 2008 9:08 PM:
Yeah. I was like Eyes bulged. Didn’t expect it. Glad I’m not the only one who sat around for this haha
Going to order this RIGHT now wherever I can.
antaraa replied on June 24, 2008 9:20 PM:
Already ordered mine from TechShopStopUK. Get it soon or they’re ganna be sold out like mad after the review here.
First site to reveal it. Owned
4870 looks so good. Definitely must have. Not a GTX guy after knowing the specs for it. Oh and I’m not dumb
PCEnthusiast replied on June 24, 2008 9:16 PM:
Yeah a real must have no doubt
You’re not the only one. I was up to the edge when it was at 17 secs
IntelLover replied on June 24, 2008 9:12 PM:
for me 5 secs ; )
Awfully nice. Seriously
This is grandeur
AMD Revamp indeed. I think NVIDIA can throw in the white flag now.
I’m just seriously amazed by all the features and specs. And then those AA methods against CSAA. Haha CSAA is history
Very impressed by this
Gizz is right, so happy by all these specs. Glad it didn’t disappointed and wasn’t just hype. Then again, I know WhatIfGaming don’t do hype.
GDDR5 memory + GDDR3 superior clocked on 50? Count me in for both for all of my PC’s
This is really overwhelming. Thanks
TY so much
No one in India ship 4850 or 4870. I want to cry cause specs look nice. ; ( I order international now but shipp fees is hurting! xD
Get over it Vash. It’s really worth it for the 70’s and 50’s. Just do it =)
Wonderful article. Am I late to the parteh ?!
HA! Stayed up late for this. Comment is good to go, and I will definitely be buying the 4850 because of the previous review.
Awesome article as usual. Thx
Oh gosh. Can’t wait for that review from here. It’s going to be epic.
Really nicely detailed article as always. Thank you <3 bf will want to see it ASAP. He actually thought it would end 3 hours later, but it’s pacific.