X-bit labs

NVIDIA Multi-GPU SLI Technology: New Approach to Old Ideas (page 13)

Category: Video

by Alexey Stepin , Yaroslav Lyssenko, Anton Shilov

[ 02/25/2005 | 02:15 PM ]

Testbed Configurations and Methods

We made use of three test platforms that were configured like follows:

NVIDIA nForce4 SLI platform:

• AMD Athlon 64 4000+ CPU (2.40GHz, 1MB L2 cache);
• ASUS A8N-SLI Deluxe mainboard;
• OCZ PC-3200 Platinum EB DDR SDRAM (2x512MB, CL2.5-3-2-8);
• Samsung SpinPoint SP1213C hard disk drive (Serial ATA-150, 8MB buffer);
• Creative SoundBlaster Audigy 2 sound card.

PCI Express platform:

• Intel Pentium 4 560 CPU (Socket 775, 3.60GHz, 1MB L2 cache);
• Intel Desktop Board D925XCV;
• 2x512MB PC2-4300 DDR2 SDRAM from Micron Technology;
• Samsung SpinPoint SP1213C hard disk drive (Serial ATA-150, 8MB buffer);
• Creative SoundBlaster Audigy 2 sound card.

AGP platform:

• AMD Athlon 64 4000+ CPU (2.40GHz, 1MB L2 cache);
• ABIT KV8 Pro mainboard;
• OCZ PC-3200 Platinum EB DDR SDRAM (2x512MB, CL2.5-3-2-8);
• Samsung SpinPoint SP1213C hard disk drive (Serial ATA-150, 8MB buffer);
• Creative SoundBlaster Audigy 2 sound card.

Software:

• Microsoft Windows XP Pro SP2, DirectX 9.0c;
• ATI Catalyst 4.12;
• NVIDIA ForceWare 66.93.

We had to use the Intel Pentium 4 platform to test PCI Express graphics cards on ATI’s RADEON GPUs since the ASUS A8N-SLI Deluxe mainboard wouldn’t start up with them with the older version of its BIOS.

Since the NVIDIA nForce4 SLI platform and the testbed based on the VIA K8T800 Pro used the same processor (Athlon 64 4000+), we decided to compare the results of the SLI configurations with the results of single AGP 8x cards. We think this comparison is quite correct for today.

To avoid confusion, we mark the NVIDIA nForce4 SLI platform with an asterix (*) and the Intel 925X platform with a cross (†) in the diagrams.

Besides the GeForce 6800 Ultra and GeForce 6600 GT cards we united in the SLI mode, we had the following graphics cards in our tests:

AGP graphics cards:

• NVIDIA GeForce 6800 Ultra 256MB (400MHz/1100MHz)
  For details see our article called Leadtek WinFast A400 Ultra TDH Graphics Card Review;
• NVIDIA GeForce 6600 GT AGP 128MB (500/900MHz);
• ATI RADEON X800 XT Platinum Edition 256MB (520/1120MHz).

PCI Express graphics cards:

• NVIDIA GeForce 6800 GT 128MB (350/1000MHz);
• NVIDIA GeForce 6600 GT 128MB (500/1000MHz)
  For details please see our article called NVIDIA GeForce 6600 GT Assaults Mainstream Gaming Market;
• ATI RADEON X850 XT Platinum Edition 256MB (540/1180MHz)
  For details please see our article called ATI RADEON X850 Platinum Edition: Good Things Go Better;
• ATI RADEON X700 XT 256MB (475/1000MHz)
  For details please see our article called ATI RADEON X700 XT: Architecture Preview;

The Catalyst A.I. option was set to “Standard”, and the Mipmap Detail Level option to “Quality”. We disabled VSync in the drivers for all the participating cards. We also turned off the ForceWare optimizations save for the Anisotropic mip filter optimization, using the Quality mode.

We turned on full-screen antialiasing and anisotropic filtering from the game’s own menu. Otherwise we forced the necessary mode from the driver. The maximum graphics quality settings were selected in each game, the same for graphics cards on ATI’s and NVIDIA’s GPUs.

We enabled the Multi-GPU Rendering mode for the SLI platform, i.e. we forced the SLI mode even for games the ForceWare driver doesn’t officially support. Thus we checked out how efficient SLI technology is in such cases, if it works at all.