When building an SLI PC, NVIDIA recommends using an SLI-Ready certified power supply. Check here for the complete list of certified power supplies. As an additional recommendation, NVIDIA provides the following power supply guidelines for SLI PCs:
Extreme SLI PC*:
NVIDIA has tested the majority of power supplies in this high power category and therefore only recommends an SLI-Ready power supply.
Ultra High-End SLI PC*:
You must have a power supply that can provide a minimum of +12V @ 22A of dedicated power for the two graphics cards. Of this 22A requirement, +12V @ 5.5A must be available to each of the two PCI Express 6-pin auxiliary power supply connectors. The remaining 11A must be supplied to the motherboard for dedicated graphics card use.
High-End SLI PC*:
Minimum of 500-600W Power Supply with a minimum of +12V @ 30A for all PC components.
Mid-Range SLI PC*:
Minimum of 450-500W Power Supply with a minimum of +12V @ 26A for all PC components.
Entry-Level SLI PC*:
Minimum of 400-450W Power Supply with a minimum of +12V @ 22A for all PC components.
*Note: These power supply recommendations are based on the following test configurations using standard component clock speeds:
Extreme SLI PC Configuration:
Dual GeForce 8800 Ultra, Dual GeForce 8800 GTX, Dual GeForce 8800 GTS or Dual GeForce 7950GX2
AMD Athlon 64 FX-62 2.8GHz (AM2) or Intel Core 2 Extreme X6800 2.9GHz
NVIDIA nForce 680 SLI or NVIDIA nForce 590 SLI motherboard with 2GB system memory
Two HDDs in Raid 0 configuration
Two optical drives
PCI Sound Card
LCD at 2560x1600 resolution
Ultra High-End SLI PC Configuration:
Dual GeForce 7900 GTX or Dual GeForce 7800 GTX 512MB
Intel Core 2 Duo or AMD Athlon 64 FX-60
NVIDIA nForce 680i SLI or NVIDIA nForce 590 motherboard with 2GB system memory
Two HDDs in Raid 0 configuration
Two optical drives
PCI Sound Card
LCD at 1600x1200 resolution
High-End SLI PC Configuration:
Dual GeForce 7800 GTX 256MB or Dual GeForce 6800 Ultra
Intel Core 2 Duo or AMD Athlon 64 FX-57
NVIDIA nForce 680i LT SLI or NVIDIA nForce 590 motherboard with 2GB system memory
Two HDDs in Raid 0 configuration
Two optical drives
PCI sound card
LCD at 1600x1200 resolution
Mid-Range SLI PC Configuration:
Dual GeForce 8600 GTS, 7900 GT, 6800 GT, or 6800
Intel Core 2 Duo or AMD Athlon 64
NVIDIA nForce 650i SLI or NVIDIA nForce 570 SLI motherboard with 1GB system memory
Single HDD
Two optical drives
PCI sound card
LCD at 1600x1200 resolution
Entry-Level SLI PC Configuration:
Dual GeForce 8600 GT, 8500GT, 7600GT, 6600 GT, or 6600
Intel Core 2 Duo or AMD Athlon 64
NVIDIA nForce 650i SLI or NVIDIA nForce 570 SLI motherboard with 1GB system memory
Single HDD
One optical drive
LCD at 1600x1200 resolution
