SLI (Scalable Link Interface), two or more graphic cards work together

I am selling this huge desktop computer before moving campus.

The computer was a high-end built, offering great quality and stylish looking. It is still powerful for both commercial applications and gaming. The case and power supply support SLI and they will serve for quite long time as a high-end platform for your following upgrades of hardware. They value over $100 now.

Case: Thermal Take Armor super-tower professional case (6xHDD air-cooled HDD bays; 5x large cooling fans; super strong and plenty of room. One external USB port on the top is not working.) Link:

http://www.xoxide.com/thermaltake-armor-case-250mm-black.html?gclid=CInPw7Hw2LYCFWXZQgodfzYADA

Power supply: OCZ GXS 700 (OCZ GameXStream OCZ700GXSSLI 700W ATX12V SLI Certified CrossFire Ready Active PFC Power Supply)

Mainboard: EVGA nForce 680i SLI (should support all Core2 DUO and Core2 Quad CPUs)

CPU: Core2 DUO E6750 2.66G dual-core FSB1333

Graphic Card: EVGA 8800GTS 640M (2xDVI, with VGA adapters, still very powerful now)

OCZ SLI-ready DDRII 800 2Gx2

160G+640G SATA HDD

DVDRW

***I can throw in a 15 inch LCD monitor for free if you would like a monitor.