SLI stands for Scalable Link Interface. You might remember a company called 3dfx which went bankrupt in December of 2000. They were a manufacturer of 3D video chips, much like NVIDIA is today. One of my first 3D video cards was a Monster3D from Diamond Multimedia. This card was the fastest, most feature-rich 3D card at the time it was launched in 1996. The replacement for the Voodoo Graphics chip on the Monster3D was called the Voodoo 2. The Voodoo 2 was fast, but one of it's unique features at the time was the ability to work with a second Voodoo 2, doubling performance. This was called SLI (Scan Line Interleave).

To work in SLI mode, you need several components; a SLI-capable motherboard, 2 video cards of the same type, a SLI bridge, and a powerful power supply. NVIDIA kindly provided the site with nearly a complete system including motherboard, case, memory, 2 6800GTs, floppy drive, hard disk. I will cover the motherboard more in detail a little later in the review. The currently available SLI video cards include the 6600GT, the 6800, the 6800GT, and the 6800 Ultra.

There are three basic modes of SLI; AFR, SFR and Compatibility mode. AFR is Alternate Frame Rendering. Each graphics card renders one frame in sequence. Card 1 would render frame 1. Card 2 would render Frame 2 etc. This has the advantage of each card being independent of each other in rendering frames. SFR stands for Single Frame Rendering. This mode splits the workload between the two cards. This has the advantage in a game that has particular areas where one frame is rendered faster than the other. In some situations, AFR would cause one of the cards to wait on the other, causing a delay.

SLI supported applications
Age of Mythology
Aquanox 2: Revelation
Armed and Dangerous
Battlefield 1942
Battlefield 2
Battlefield Vietnam
Breed
Brothers in Arms
Colin McRae Rally 2005
Colin McRae Rally 04
Conan
Dark Age of Camelot: Atlantis
Dirt Track Racing 2
Doom 3
Everquest
Far Cry
Everquest II
FlatOut
Ground Control II: Operation Exodus
Guild Wars
Half Life 2
Halo: Combat Evolved
IL-2 Sturmovik: Forgotten Battles
Joint Operations: Typhoon Rising
Kohan II: Kings of War
Lineage II: The Chaotic Chronicles
Madden NFL 2005
Max Payne 2: The Fall of Max Payne
Medal of Honor: Allied Assault
Medal of Honor: Breakthrough
Medal of Honor: Spearhead
NBA Live 2005
Need for Speed Underground 2
Painkiller
Painkiller: Battle Out of Hell
Perimeter
Prince of Persia: The Sands of Time
Quake III
Serious Sam: The Second Encounter
Sims 2
SpellForce
Splinter Cell
Splinter Cell: Chaos Theory
Star Wars: Battlefront
Star Wars: Republic Commando
SWAT 4
Thief: Deadly Shadows
ToCA Race Driver 2
Tomb Raider: The Angel of Darkness
Tony Hawk’s Underground
Tribes Vengeance
Tron 2.0
Unreal
Unreal 2
Unreal Tournament 2003
Vampire: The Masquerade Bloodlines
Warhammer 40,000: Dawn of War
World of Warcraft
X2 the Threat
Xpand Rally
3DMark2001
3DMark03
3DMark05
Aquamark 3
Codecreatures Pro
Dawn: NVIDIA Demo
HDRLighting
Nalu: NVIDIA Demo
Trees of Pangaea

The list of games and applications supported by NVIDIA’s SLI is quite extensive and has grown since NVIDIA released the SLI chipset for Athlon64 last year. Some later games like Act of War aren’t supported yet. NVIDIA has released two drivers since SLI was released for the Athlon64 platform adding new games and applications to their list of supported games. Playing games with SLI is a good experience. Of course, a 6800GT is a good card by itself. When paired with a second 6800GT supported games are likely to be CPU limited.