I'm a first time builder and have one 500 GB HDD, and am considering purchasing an 80 GB HDD. Assuming I will not set up RAID (don't see the point), what is the best way to optimize two HDD? I read some posts about putting the OS and applications on the smaller HDD, and using the bigger one for data storage. My question is - how does the OS know to use one HDD to boot, and the other for data storage? What's the best way to set all this up?

Please forgive my slight ignorance on this subject...

I think it's a good idea to split on 2 hd.

Basically, in the BIOS of the motherboard you can specify the boot order, you will be able to specify which HD to look at first see if there's a OS.

Once the HDs are detected the computer will look for the Boot.ini file on the HD where the OS is install.

So all you have to do is make sure both HD are detected. Then you boot with your windows CD and choose which HD you want to use for the OS(pretty obvious when you got a 80gig and a 500gig..).

I also suggest moving the SWAP file to the "storage"HD and also to redirect the My Documents to that HD. This way, a OS re-install/re-imaging is really guick

size doesn't matter. Speed does. Put the OS on the FASTER HD and install all of your speed-insensative background applications to the other HD. Normally you would also make this "other" drive your storage drive as you bought a big cheap HD to use for storage and it was slow but where you put your storage doesn't effect performance unless you're accessing the storage while doing some other drive-latency sensitive task. The only think I can think of where you would be doing this is listening to music while loading game levels. From an absolute performance perspective you don't want your storage to be on the same drive as your OS, swap, or time-sensitive apps but if you're choosing from a given set of hardware always put your OS on the fastest drive.

So, it's not the *size* of the second HD that you're thinking about buying that's important it's the speed. You've got storage fairly well covered with the 500gb so pick out something fast and don't worry about size. www.storagereview.com is my favorite review site right now. If you currently owned some slow 80gb drive I'd tell you to get a fast 500gb drive and install your OS on it or to buy 2 new drives (but obviously that would cost more).