X-bit labs

Monday, July 25, 2005

ATI RADEON X850 CrossFire – Faster than GeForce 7800 GTX. ATI CrossFire Benchmarks Published

The formal launch of ATI CrossFire multi-GPU technology took place over two months ago and the commercial release of appropriate hardware was promised to be scheduled by this time then. Right now there is no CrossFire on the market and it is still unclear how efficient the technology is. AnandTech web-site has managed to obtain suitable CrossFire graphics cards and mainboard in order to pull the wraps off ATI’s multi-GPU technology performance.

The web-site ran into multiple issues with the CrossFire setup due to the fact that the hardware used was not final. Six modern games – Doom III, Everquest 2, Far Cry, Half-Life 2, Splinter Cell: Chaos Theory and Unreal Tournament 2004 – were used for testing. Even though in all of those benchmarks ATI’s CrossFire delivered significant performance improvement, the web-site noted that neither high-quality full-scene antialiasing, nor rendering modes different from SuperTiling could be enabled. Furthermore, multi-GPU RADEON X850 setup does not deliver tangibly higher performance compared to the GeForce 7800 GTX.

“While CrossFire often provides more performance than the 7800 GTX, we don't get the benefit of SM3.0, which is being used in more and more games. The added cost will either eat into your budget for a next generation card when they come along, or will usurp money that might be better spent on a monitor to handle very high resolutions,” AnandTech claims.

“The bottom line is that CrossFire is a success in implementation. We are impressed with the performance of the solution, especially considering the very early hardware and software that we have our hands on here. When a final solution is released, we will be doing a much more in-depth performance and image quality analysis of the hardware, but at this point, we just want to get a solid idea about what to expect,” the web-site believes.

• AnandTech: AnandTech Exclusive: CrossFire Benchmarks Revealed .
• X-bit labs: ATI Crosses the Swords: Multi-GPU CrossFire Technology Previewed.
• X-bit labs: Web-Site Reveals ATI RADEON X850 CrossFire Benchmark Results.

NVIDIA’s SLI Antialiasing Benchmarked. NVIDIA’s SLI Antialiasing Adds Clarity to Games

While ATI has not yet commercially released its multi-GPU platform, NVIDIA widens the number of features available only to owners of multi-GeForce configurations. In order to meet ATI CrossFire platform fully equipped, NVIDIA has introduced additional eye-candy features in the latest beta ForceWare drivers which are available for download at nZone web-site. In particular, the most-recent flavour of the driver adds new SLI rendering mode – SLI antialiasing.

“SLI Antialiasing is a new standalone SLI rendering mode that offers up to double the antialiasing performance by splitting the antialiasing workload between the two graphics cards. When enabled, SLI Antialiasing offers 2 new antialiasing settings: SLI8x and SLI16x,” claims NVIDIA’s statement.

The question which a number of web-sites have decided to address is whether 16x and 8x antialiasing modes really provide image quality benefits and whether performance in such modes is still decent to play games.

“Take, for instance, the case of the 8X SLI antialiasing mode. This mode is actually a doubled-up version of NVIDIA’s 4X multisampled antialiasing method. Each card renders the scene with 4X multisampled antialiasing, but their sample positions are slightly offset, or jittered, to make them distinct from one another. The two resulting sets of samples are then combined, yielding eight coverage samples and two texture samples, which are blended to achieve the final pixel color. The result should be the equivalent of NVIDIA’s familiar “8xS” antialiasing mode, except that the sampling patterns for SLI AA are a little bit different,” explains The Tech Report.

“One feature that is incredibly important is that SLI-AA works with nearly every game out there. No matter if it is Direct3D or OpenGL, or if it has problems with SLI AFR or SFR modes, the application will benefit from these antialiasing modes.  NVIDIA is promising a 100% compatibility with all 3D games with the SLI AA modes.  If the game can run on NVIDIA hardware, it can run with SLI-AA. Except of course games that do not support antialiasing in any way (like the first two Splinter Cell games) or applications utilizing FP16 HDR rendering (Splinter Cell 3 and Far Cry),” writes PenStar Systems.

“Doing some performance testing, we found many situations where SLI 8X and 16X AA modes were playable. Half-Life 2, for example, is very playable at 1600x1200 with SLI 16X AA mode. Where these Antialiasing modes really come in handy is in CPU limited games. For example, a game like Flight Simulator 2004 lets you enable the SLI 8X and 16X AA modes to experience much better image quality with a very small performance hit as this simulator is CPU limited and not GPU limited. There are also many older games where performance is very fast on the GeForce 7800 GTX SLI setup. Therefore, these new AA modes should also work well in older games,” concludes [H]ardOCP.

• nZone: ForceWare Version 77.76 Download.
• SLIZone: SLI Antialiasing: Redefining Image Quality.
• [H]ardOCP - NVIDIA SLI Antialiasing.
• PenStar Systems, LLC: NVIDIA Forceware 77.76 Preview.
• The Tech Report: SLI antialiasing debuts.