ATI's Late Response to G70 - Radeon X1800, X1600 and X1300
by Derek Wilson on October 5, 2005 11:05 AM EST- Posted in
- GPUs
High Quality AF
One of the greatest things about the newest high end hardware from NVIDIA and ATI is that advanced filtering features can be enabled at any resolution while still maintaining playable framerates. It may take developers a little while to catch up to the capabilities of the X1800 and 7800 lines, but adding value through advanced quality features is definitely a welcome path for ATI and NVIDIA to take. For this launch, ATI has improved their AA and AF implementations. We also have two brand new features: Adaptive AA and Area Anisotropic filtering.
Starting with Area Anisotropic (or high quality AF as it is called in the driver), ATI has finally brought viewing angle independent anisotropic filtering to their hardware. NVIDIA introduced this feature back in the GeForce FX days, but everyone was so caught up in the FX series' abysmal performance that not many paid attention to the fact that the FX series had better quality anisotropic filtering than anything from ATI. Yes, the performance impact was larger, but NVIDIA hardware was differentiating the Euclidean distance calculation sqrt(x^2 + y^2 + z^2) in its anisotropic filtering algorithm. Current methods (NVIDIA stopped doing the quality way) simply differentiate an approximated distance in the form of (ax + by + cz). Math buffs will realize that the differential for this approximated distance simply involves constants while the partials for Euclidean distance are less trivial. Calculating a square root is a complex task, even in hardware, which explains the lower performance of the "quality AF" equation.
Angle dependant anisotropic methods produce fine results in games with flat floors and walls, as these textures are aligned on axes that are correctly filtered. Games that allow a broader freedom of motion (such as flying/space games or top down view games like the sims) don't benefit any more from anisotropic filtering than trilinear filtering. Rotating a surface with angle dependant anisotropic filtering applied can cause noticeable and distracting flicker or texture aliasing. Thus, angle independent techniques (such as ATI's area aniso) are welcome additions to the playing field. As NVIDIA previously employed a high quality anisotropic algorithm, we hope that the introduction of this anisotropic algorithm from ATI will prompt NVIDIA to include such a feature in future hardware as well.
We sat down with the D3DAFTester to show the difference between NVIDIA and ATI hardware with and without the high quality mode enabled. Here's what we ended up with:
One of the greatest things about the newest high end hardware from NVIDIA and ATI is that advanced filtering features can be enabled at any resolution while still maintaining playable framerates. It may take developers a little while to catch up to the capabilities of the X1800 and 7800 lines, but adding value through advanced quality features is definitely a welcome path for ATI and NVIDIA to take. For this launch, ATI has improved their AA and AF implementations. We also have two brand new features: Adaptive AA and Area Anisotropic filtering.
Starting with Area Anisotropic (or high quality AF as it is called in the driver), ATI has finally brought viewing angle independent anisotropic filtering to their hardware. NVIDIA introduced this feature back in the GeForce FX days, but everyone was so caught up in the FX series' abysmal performance that not many paid attention to the fact that the FX series had better quality anisotropic filtering than anything from ATI. Yes, the performance impact was larger, but NVIDIA hardware was differentiating the Euclidean distance calculation sqrt(x^2 + y^2 + z^2) in its anisotropic filtering algorithm. Current methods (NVIDIA stopped doing the quality way) simply differentiate an approximated distance in the form of (ax + by + cz). Math buffs will realize that the differential for this approximated distance simply involves constants while the partials for Euclidean distance are less trivial. Calculating a square root is a complex task, even in hardware, which explains the lower performance of the "quality AF" equation.
Angle dependant anisotropic methods produce fine results in games with flat floors and walls, as these textures are aligned on axes that are correctly filtered. Games that allow a broader freedom of motion (such as flying/space games or top down view games like the sims) don't benefit any more from anisotropic filtering than trilinear filtering. Rotating a surface with angle dependant anisotropic filtering applied can cause noticeable and distracting flicker or texture aliasing. Thus, angle independent techniques (such as ATI's area aniso) are welcome additions to the playing field. As NVIDIA previously employed a high quality anisotropic algorithm, we hope that the introduction of this anisotropic algorithm from ATI will prompt NVIDIA to include such a feature in future hardware as well.
We sat down with the D3DAFTester to show the difference between NVIDIA and ATI hardware with and without the high quality mode enabled. Here's what we ended up with:
NVIDIA 7800 GTX AF
NVIDIA 7800 GTX AF
Mouse over to cycle images
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DerekWilson - Friday, October 7, 2005 - link
Hello,Rather than update this article with the tables as we had planned, we decided to go all out and collect enough data to build something really interesting.
http://anandtech.com/video/showdoc.aspx?i=2556">http://anandtech.com/video/showdoc.aspx?i=2556
Our extended performance analysis should be enough to better show the strengths and weaknesses of the X1x00 hardware in all the games we tested in this article plus Battlefield 2.
I would like to apologize for not getting more data together in time for this article, but I hope the extended performance tests will help make up for what was lacking here.
And we've got more to come as well -- we will be doing an in-depth follow up on new feature performance and quality as well.
Thanks,
Derek Wilson
MiLLeRBoY - Thursday, October 6, 2005 - link
If NVIDIA puts out a 7800XT with a bigger cooler, which makes the video card dual slots, instead of just one slot. This would allow them to increase the speeds of the RAM and GPU. And if they increase it to 512MB ram, they will knock ATI’s X1800XT off the map completely.MiLLeRBoY - Thursday, October 6, 2005 - link
oops, 7800 GTX, I mean, lol.stephenbrooks - Thursday, October 6, 2005 - link
Maybe a solution for all the complaints about review-quality would be for AnandTech to put its reviews through "beta"? :pwaldo - Thursday, October 6, 2005 - link
So, I am back, and as always confused!Where are we now? We have at THG the same card beating teh 7800GTX hands down in several instances....and here at Anand, we have the ATI version barely holding its head above water.....talk about weird inconsistencies....someone is tweaking the numbers or the machines....one or the other.
Some of me would like to give the nod to THG because they have a history of doing more accurate more complete video card reviews, but this is just crazy....can someone at Anand please explain, cause well, I know THG won't.
tomoyo - Thursday, October 6, 2005 - link
In terms of pricing, I think Nvidia has Ati beaten in every category of card currently.I think the competition that ATI is marketing each card against is as follows(even if the prices have a huge disparity currently):
X1800XT vs 7800GTX
X1800XL vs 7800GT
X1600XT vs 6800/6600GT
X1600Pro vs 6600GT/6600
x1300Pro vs 6600
x1300 vs 6200
From what I've seen of the reviews from anandtech, techreport, and a couple other sources it looks like the X1800XT/XL are pretty competitive with their competition, however I really dislike the extra power consumption and of course the cost of the card. I think the 7800 is a far better solution in terms of most categories except a few minor features like having HDR/AA at the same time. It looks like it's possible the X1800 might have some gains in future games because of the better memory controller and threading pixel shader, but it seems rather useless for now.
The x1600 looks like the biggest disappointment by far. It's nowhere near the league of the 6800 cards and barely outperforms the 6600gt, which has a huge price advantage. The x800gto2 looks like a far better card than the x1600 here. Personally I'm hoping nvidia does what's expected and puts out a 90nm 7600 that has a decent performance gain over the 6600gt. That might be one of the best silent computing cards around when it comes out. (I'm hoping to replace my 6600 with this now that the x1600 is no upgrade for me)
The x1300 actually looks like the most promising chip to me. It's obviously not worthwhile for gamers, but I think it might turn out to be a pretty good drop-in card for non-gaming systems. It's all dependent on whether it can hit the price point for the under $100(or is that under $70) market well. It certainly looks like it'll outperform the 6200 and x300 and be the new standard for entry level systems... until nvidia's next entry card. Not to mention most of the x1x00 generation features are still included with the x1300 card.
AtaStrumf - Thursday, October 6, 2005 - link
Totaly disappointed in both ATi and AT.As for X1300 don't forget this is the best version out of X1300 family and I can't help but remember the FX 5200 Ultra, which looked great but was never really available, because they could not produce it at low enough price point. I think same will happen here.
bob661 - Thursday, October 6, 2005 - link
Very nice summary.andyc - Wednesday, October 5, 2005 - link
So what card is the "real" competitor to the 7800GT, becuase frankly, I'm totally confused which card ATI is trying to use to compete against it.Pete - Wednesday, October 5, 2005 - link
X1800XL.