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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GoatMonkey - Wednesday, October 5, 2005 - link
What?!?! But it's **EXTREME**kilkennycat - Wednesday, October 5, 2005 - link
...there is an old saying. "Wait to see the whites of their eyes before shooting". Pre-orders mean nothing and delivery dates can change. Never ever order from a vendor that has a pre-order queue, unless you really don't care when you get the item. Who knows where you are in this queue? Few, if any of such vendors ever give you this information - for the obvious reason that thery don't want to risk losing the order. The first shipment might be 5 pieces and you are 20th on the list. Order product from vendors like Newegg or ZipZoomFly that sell only from available stock, but also have immediate auto e-mail notification when a sold-out item is back in stock... first come, first serve then of course, but at least the customer is never ever 'left hung out to dry'.I personally view vendors with pre-order queues as somewhat sleazy, but maybe my view is extreme. A pre-order queue is entirely to the benefit of the vendor and not the customer.
southpawuni - Wednesday, October 5, 2005 - link
Bad results from ATI.Look at the midrange.. I'm guessing most people around here buy that hardware (6800GT/7800GT)..
disappointing day for ATI.
Since the NV cards have been out, and are priced right.. I dont see much hope for ATI now.
bob661 - Wednesday, October 5, 2005 - link
I was expecting the new ATI cards to be a bit more competitive especially given that they'll be more expensive. Wow, what a shocker! The X1600 isn't even worth buying at less than or equal to 6600GT performance at 6800GT prices. What a bargain!!!segagenesis - Wednesday, October 5, 2005 - link
They are simply arriving late to the game. I curious see how anyone will really want the X1800 XL over the 7800 GT, consideing the price.And why no show all the cards on each graph? Why is the 7800 GT missing on the Day of Defeat graph? Are we not trying to compare cards?
Questar - Wednesday, October 5, 2005 - link
Simple - Image quality.It's been reported just about everywhere else that Nvidia lowered the image quality on the 7800 to gain speed. The image quality comparison in this review proves it.
Questar - Wednesday, October 5, 2005 - link
Heh, modded down by the Nvidia fanboys already!How about this guys, enable HDR and AA in any game you would like on a 7800. Oops, can't do it!
Open your eyes and look at the AF charts in this review. ATI has better AF, period.
segagenesis - Wednesday, October 5, 2005 - link
They looked like crap to me honestly. And where are you getting this crap about no AA/HDR on nVidia cards? Are you trying to troll? No wonder you got modded down.Questar - Wednesday, October 5, 2005 - link
It's not crap. A 7800 can't do HDR and AA at the same time. Read the HOCP review where they explain this.JarredWalton - Wednesday, October 5, 2005 - link
It was mentioned in this article as well. However, HDR already kills performance, and HDR + AA is going to be unplayable on anything short of Crossfired X1800 XT cards. Then again, HDR at 1600x1200 really isn't dying for 4xAA support, and I think many people looking at HDR are running very high-end displays and GPUs.