A few days ago, a forum member posted information regarding image quality concerns with popular flight combat game Tom Clancy H.A.W.X. There has been much debate about this across the net over the weekend. KitGuru followed up on the forum post to clarify exactly what was being noticed.
As we discussed in our article, the points were being raised in the KitGuru forum, there appeared to be a difference in image quality levels and those differences appear to give an ~8% boost to the GTX570/580 cards. We were clear that our own testing was to happen next week and we invited nVidia to come back to us on the subject if there were any innaccuracies or misunderstandings.
Big thanks to nVidia for taking our concerns seriously.
Nvidia’s Nick Stam has addressed these issues himself, responding to KitGuru. Nick Stam is nVidia’s Technical Marketing Director. His team provides technical support to Web and print tech media, industry analysts, and business partners. Nick’s team also generates reviewer guides and technical whitepapers.
We felt it was important to highlight his reply via KitGuru to our readers so he can clear up any concerns.
What is being experienced is not an “Antialiasing cheat” but rather a HawX bug that is fixed by our driver using an application specific profile.
In a nutshell, the HawX application requests the highest possible AA “sample quality” at a particular AA level from our driver. Without our driver fix, the game would be running 16xCSAA instead of standard 4xAA when you select 4xAA in-game. It runs the proper 4xAA with the driver fix. You defeat the fix by changing the .exe name, causing it to run at 16xCSAA.
You may remember that Geforce 8800 introduced Coverage Sampling AA (CSAA) technology, which added higher quality AA using little extra storage. Prior to 8800 GTX and CSAA, there was only one “sample quality level” for each AA level, so if an application requested four AA samples, the hardware performed standard 4xAA. However, with 8800 GTX GPUs onwards, our drivers expose additional sample quality levels for various standard AA levels which correspond to our CSAA modes at a given standard AA level.
The “sample quality level” feature was the outcome of discussions with Microsoft and game developers. It allowed CSAA to be exposed in the current DirectX framework without major changes. Game developers would be able to take advantage of CSAA with minor tweaks in their code.
Unfortunately, HawX requests the highest quality level for 4xAA, but does not give the user the explicit ability to set CSAA levels in their control panel. Without the driver profile fix, 16xCSAA is applied instead of standard 4xAA. Recall that 16xCSAA uses 4 color/Z samples like 4xAA, but also adds 12 coverage samples. (You can read more about CSAA in our GeForce 8800 Tech Briefs on our Website).
When you rename the HawX.exe to something else, the driver profile bits are ignored, and 16xCSAA is used. Thus the modest performance slowdown and higher quality AA as shown in the images.
To use “standard” 4xAA in a renamed HawX executable, you should select any level of anti-aliasing in the game, then go into the NVIDIA Control Panel and set 4xAA for “Antialiasing Setting” and turn on “Enhance the application setting” for the “Antialiasing mode”.
Nick Stam, NVIDIA
- Was there a performance boost for the GTX570/580 cards when the HAWX application was detected? Yes.
- Was it specifically coded into the driver as an application detection? Yes.
- Was it done to cheat on performance? No.
- Was it done to overcome an issue being experienced in the game by nVidia cards? Yes.
- In overcoming the coding issue, was a side effect an ~8% performance boost in some benchmarks? Yes.
- Was the 8% faster score delivered with the 4xAA originally set by the user? YES
So, there you have it. We really appreciate Nick’s quick and honest response, which we have – as promised – published in full.
KitGuru readers should feel free to flag any issues you see like this in our forums or to our editorial team. We will investigate all of them and publish any that we believe have merit (screen shots and system specs always appreciated).
KitGuru says: BIG THANKS to our forum members for raising it and BIG THANKS to Nick for addressing it. Hopefully this puts the matter to bed !