The larger SATA HDDs will work off of the SAS controllers but I doubt you'd be able to boot from them into Windows. I don't think most manufacturers were using UEFI at that time and Windows absolutely requires UEFI to boot from an HDD larger than 2 TB. You can simply install Windows to the 300 GB SAS drive and then use the 4 and 6 TB drives for bulk data storage though.
okcnaline :
I would say get cheaper dual CPU computers. Ones that use the Intel 5000X chipset, because those are way cheaper.
No, don't. The LGA1366 units are a BUNCH faster than anything that came in LGA771 with the 5000X chipset. LGA771 was the last hurrah of the hoary old front-side bus which severely crippled performance on multiprocessor systems compared to a modern on-CPU memory controller such as the LGA1366 and later units use. The 5000X chipset also runs hotter than stink as does the expensive, laggy FB-DIMM memory it uses.
As you can guess, I have a file server with two LGA771 Xeon X5260s, a 5000X motherboard, and 12 GB of FB-DIMMs sitting off to my right side. It's not a bad computer but I would trade it in a heartbeat for a dual 1366 system. Or for that matter an AMD dual Socket F or C32 machine.