Which controller do you have?

Well, I would assume the chipset drivers would be native to Windows 8, but you can try the Windows 7 AHCI/chipset/storage drivers for that system:

http://www.dell.com/support/drivers/us/en/04/DriverDetails/Product/precision-t3500?driverId=9NCD1&osCode=W764&fileId=3098295648&languageCode=EN&categoryId=SA

Dell usually provides backward compatibility for business systems, but rarely forward compatibility.  That doesn't mean it won't work - they just don't supply any needed drivers.

It's just the built-in Intel controller - we did not choose a PERC controller.