was just wondering if you can still separate the Operating system from the rest of the hard drive space in a Raid 0 setup by using a partition like you can in normal mode.
Yes, provided you're not doing a software RAID.
would I get some of the same benefits as raid0 by not using a raid setup, but putting my OS on a separate hard drive from one of my more intensive programs that relies on the hard drive a lot.
That depends on the quality of your RAID controller and the speed of your drives. If you're using a poor quality RAID controller, such as one integrated on to your motherboard, then you're probably better off with two separate drives: one of operating system, one for swap and data. If you've got a high-quality controller and fast drives, then you might see some performance increase with a RAID 0.
However, RAID 1 will increase your fault tolerance as well as your read speeds. So, if you're concerned about game load times, RAID 1 will help more than RAID 0. Although, the margin of difference will probably be negligable and nearly 100% of the time I do not advice RAID on consumer-level systems.