Can you run sli and crossfire in the same system

No...the motherboard supports one or the other,not both

A mobo can have the ability to run SLI and Crossfire. Therefore, if you have enough slots, you can. But you can't combine the two you have to at least have 1 monitor for each SLI/Crossfire.

if you have a mb with a Lucid Hydra controller then you can infact run the two together but you need a board like the Asus Crosshair IV Extreme but you don't get very much of a performance boost. Better sticking off with one or the other.

I was thinking of the Asus Rampage III Black Edition. My goal is to run the 21" crt's off the xfx crossroads and the 24" LEDs off the evga's SLI. I want to get back into graphic design AND want an amazing gaming machine. I will list my pc here within 48hrs. I am looking for some feedback as to whether or not this system would run.

I am pretty good with computers, just not the best at building them.

Jeff!

Case ( Coolermaster Haf X NVIDIA Edition TRI-SLI EATX Tower Case Green 6X5.25 5X3.5INT No PS Front USB3.0)
Alternate Case (Thermaltake Level 10 GT E-ATX Modular Tower Case 4X5.25 1X3.5 5X3.5INT No PS USB3.0 Snow Edition)
Processor (Intel Core i7 Extreme Edition 990X 6 Core LGA1366 Gulftown 3.46GHZ 12MB Processor Retail Box)
Operating System (Microsoft Windows Vista Ultimate Edition 64BIT DVD OEM)
Motherboard (ASUS Rampage III Black Edition EATX LGA1366 X58 DDR3 4PCI-E16 CrossFire SLI SATA3 USB3.0 Motherboard)
LCD Display 1 (Samsung 2443BW-HAS 24IN LCD Black 1920X1200 20000:1 DC 5ms VGA DVI HDCP Pivot Height Adjustable)
LCD Display 2 (Samsung BX2440X 24IN Widescreen LCD LED Monitor 1920X1080 5ms 5M:1DC VGA DVI-D HAS Pivot)
Memory 1 (Corsair Vengeance CMZ12GX3M3A2000C10 12GB 3X4GB DDR3-2000 CL10-10-10-27 Triple Channel Memory Kit)
Memory 2 (Corsair Vengeance CMZ12GX3M3A2000C10 12GB 3X4GB DDR3-2000 CL10-10-10-27 Triple Channel Memory Kit)
Hard Drive 1 (Corsair Performance 3 Series 256GB SATA3 6GB/S Marvell 2.5IN Solid State Disk Drive SSD)
Hard Drive 2 ( Kingston SSDNow V+ Series 512GB 2.5IN SSD SATA Solid State Disk Flash Drive Bundle)
Raid Drive 1 (Western Digital WD Caviar Black 750GB 7200RPM 64MB Buffer SATA3 3.5IN Internal Hard Drive)
Raid Drive 2 (Western Digital WD Caviar Black 750GB 7200RPM 64MB Buffer SATA3 3.5IN Internal Hard Drive)
EZ Backup Drive 1 (Western Digital My Book Essential 3TB USB 3.0 Black)
EZ Backup Drive 2 (Western Digital My Book Essential 3TB USB 3.0 Black)
Video Card 1 (EVGA GeForce GTX 590 Classified 630MHZ 3072MB 3456MHZ GDDR5 3XDVI Mini DisplayPort PCI-E Video Card)
Video Card 2 (EVGA GeForce GTX 590 Classified 630MHZ 3072MB 3456MHZ GDDR5 3XDVI Mini DisplayPort PCI-E Video Card)
Video Card 3 (XFX Radeon HD 6990 830MHZ 4GB 5.0GHZ GDDR5 4XMINIDP DVI PCI-E DIRECTX11 Video Card)
Video Card 4 (XFX Radeon HD 6990 830MHZ 4GB 5.0GHZ GDDR5 4XMINIDP DVI PCI-E DIRECTX11 Video Card)
Power Supply 1 (Thermaltake Toughpower 1200W ATX12V 20/24PIN Quad SLI Modular Power Supply Active PFC 8PIN PCI-E)
Case ( Coolermaster Haf X NVIDIA Edition TRI-SLI EATX Tower Case Green 6X5.25 5X3.5INT No PS Front USB3.0)
Alternate Case (Thermaltake Level 10 GT E-ATX Modular Tower Case 4X5.25 1X3.5 5X3.5INT No PS USB3.0 Snow Edition)
Processor (Intel Core i7 Extreme Edition 990X 6 Core LGA1366 Gulftown 3.46GHZ 12MB Processor Retail Box)
Operating System (Microsoft Windows Vista Ultimate Edition 64BIT DVD OEM)
Motherboard (ASUS Rampage III Black Edition EATX LGA1366 X58 DDR3 4PCI-E16 CrossFire SLI SATA3 USB3.0 Motherboard)
LCD Display 1 (Samsung BX2440X 24IN Widescreen LCD LED Monitor 1920X1080 5ms 5M:1DC VGA DVI-D HAS Pivot)
LCD Display 2 (Samsung BX2440X 24IN Widescreen LCD LED Monitor 1920X1080 5ms 5M:1DC VGA DVI-D HAS Pivot)
CRT Display 1 (Sony Trinitron 21" CRT)
CRT Display 2 (Sony Trinitron 21" CRT)
Memory 1 (Corsair Vengeance CMZ12GX3M3A2000C10 12GB 3X4GB DDR3-2000 CL10-10-10-27 Triple Channel Memory Kit)
Memory 2 (Corsair Vengeance CMZ12GX3M3A2000C10 12GB 3X4GB DDR3-2000 CL10-10-10-27 Triple Channel Memory Kit)
Hard Drive 1 (Corsair Performance 3 Series 256GB SATA3 6GB/S Marvell 2.5IN Solid State Disk Drive SSD)
Hard Drive 2 ( Kingston SSDNow V+ Series 512GB 2.5IN SSD SATA Solid State Disk Flash Drive Bundle)
Raid Drive 1 (Western Digital WD Caviar Black 750GB 7200RPM 64MB Buffer SATA3 3.5IN Internal Hard Drive)
Raid Drive 2 (Western Digital WD Caviar Black 750GB 7200RPM 64MB Buffer SATA3 3.5IN Internal Hard Drive)
EZ Backup Drive 1 (Western Digital My Book Essential 3TB USB 3.0 Black)
EZ Backup Drive 2 (Western Digital My Book Essential 3TB USB 3.0 Black)
Video Card 1 (EVGA GeForce GTX 590 Classified 630MHZ 3072MB 3456MHZ GDDR5 3XDVI Mini DisplayPort PCI-E Video Card)
Video Card 2 (EVGA GeForce GTX 590 Classified 630MHZ 3072MB 3456MHZ GDDR5 3XDVI Mini DisplayPort PCI-E Video Card)
Video Card 3 (XFX Radeon HD 6990 830MHZ 4GB 5.0GHZ GDDR5 4XMINIDP DVI PCI-E DIRECTX11 Video Card)
Video Card 4 (XFX Radeon HD 6990 830MHZ 4GB 5.0GHZ GDDR5 4XMINIDP DVI PCI-E DIRECTX11 Video Card)
Power Supply (Thermaltake Toughpower 1200W ATX12V 20/24PIN Quad SLI Modular Power Supply Active PFC 8PIN PCI-E)
Sound Card (Creative Sound Blaster X-FI Platinum FATAL1TY Champion Series 7.1 W/ Black Front Audio Bay & Remote)
DVD ROM (LG 18X DVD-ROM Internal SATA OEM)
DVD Writer (LG GH24LS50 24X Super Multi SATA DVD Writer OEM Black)
BLU-RAY Writer ( LG BH12LS35 Bluray Writer 12X BD-R 16X DVD+R Lightscribe 3D Ready SATA )
Floppy Drive 1 (Silverstone FP34-B 3.5IN Internal Black Aluminum 26-IN-1 Card Reader W/ Front USB Firewire & Audio)
Floppy Drive 2 (Silverstone FP35B 3.5IN Internal Black Aluminum 30-IN-1 Card Reader SDHC Front USB Firewire & Audio)

Sound Card (Creative Sound Blaster X-FI Platinum FATAL1TY Champion Series 7.1 W/ Black Front Audio Bay & Remote)
DVD ROM (LG 18X DVD-ROM Internal SATA OEM)
DVD Writer (LG GH24LS50 24X Super Multi SATA DVD Writer OEM Black)
BLU-RAY Writer ( LG BH12LS35 Bluray Writer 12X BD-R 16X DVD+R Lightscribe 3D Ready SATA )
Floppy Drive 1 (Silverstone FP34-B 3.5IN Internal Black Aluminum 26-IN-1 Card Reader W/ Front USB Firewire & Audio)
Floppy Drive 2 (Silverstone FP35B 3.5IN Internal Black Aluminum 30-IN-1 Card Reader SDHC Front USB Firewire & Audio)