I currently have a Dell CN-02XTG4-32881, ATI Radeon HD 5870 video card that I need to replace. Are there any recommendations for a replacement, would like to upgrade if possible and the computer will support it. I have a Dell Studio XPS 435t/9000 computer.

System Config:

Studio XPS 9000

Studio XPS 9000, Intel Core i7 -975 processor Extreme Edition (8MB L3 Cache, 3.33GHz)

24GB DDR3 SDRAM at 1066MHz - 6X4GB

ATI Radeon HD 5870

1.5TB Serial ATA 2 Hard Drive 7200 RPM

1.5TB Serial ATA II Hard Drive (7200RPM)

1.5TB Serial ATA II Hard Drive (7200RPM)

Windows 7 Ultimate, 64 bit, English

56K PCI Data Fax Modem

Dual Drives: DVD+/ -RW with BD- RE

Soundblaster X -Fi Titanium

Bose Companion 3 , 2.1 Stereo Audio

Dell 1525 WLAN PCIe card with1 1n mini -Card & external antenna

Update: I have the option to buy a used ATI Radeon HD 5870 for $160.00 but would like to upgrade, any recommendations, the card need to have dual DVI outputs.