New T320 curious about RAID setup

When I looked at the partitioning of the VD though there are 6 partitions on it. EFI system Partition, OEM Partition, Recovery Partition, C:, and D:. I didn't create those, I assume it was configured that way from dell.

Yes, the EFI partition is created for any Windows installation installed on a UEFI system; the OEM Partition is called Reserved Partition if using Windows media for the install, Recovery Partition is the WinRE installed on disk for startup issues/repair, and partitions are trivial and created by configured options during the ordering process.

Anyways, I was thinking about it, and it seems like it would be better if I could use 2 120GB solid state drives in a RAID 1 as 1 Virtual disk, and delete and reconfigure the virtual disk of the other 4 1TB drives as the RAID 10. Is this possible? If so, how would I go about doing it. I am pretty new to configuring servers, I have only done 1 before. What exactly are the first 4 partitions for, and do I need them? Or when I reconfigure, and instll from the included Dell OS disc, will it repartition the new RAID 1 that way? Thanks in advance.

Yes, this will work just fine. You will do this in the CTRL-R utility - you'll first delete the existing VD (RAID 10), then create a RAID 1 with your SSD's, install your OS, drivers, OMSA, then configure your RAID 10 (you can configure RAID 10 before the install, but I would wait until after the install is complete on the RAID 1). When you configure RAID, be sure to check the Advanced and Initialize boxes.

You do not need UEFI enabled ... but if you do, you will have a EFI partition; if you don't, you will not.
You will have an OEM/Reserved partition as part of a normal installation of Windows.
You will not have a Recovery partition if you install directly from the OS media.
You will have a C: partition from which Windows will run.
Other lettered data partitions will be created by you.