|"Yea I know all the drives and everything"|
If you know, then why do you need an adapter?
"I just wanted a clarify on the performance"
PATA & SATA are different technologies. Theoretically, an SATA HDD will run faster than a PATA drive (or a PATA using an SATA adapter), but the performance difference *probably* won't be noticeable to you (the user) unless you run some sort of diagnostics to compare the two. Then again, it would depend on the specs of the drives. PATA vs SATA isn't the issue as much as RPM's, buffer/cache, seek times, read/write rates, etc.
"I am actually going to put on windows 7 RC and get my dad to give me a copy on the RTM version when it comes out on MSDN"
I still don't get where you're going with this? AFAIK, the RC will not be upgradeable to the RTM. You will have to wipe the HDD & start from scratch when the RTM becomes available. M$ has said all along that the RC is for test purposes only & should NOT be used as the primary OS. It amazes me how many people have ignored this "warning". They'll be in for a rude awakening when they find they'll have to reformat/reinstall in a few months.
Windows 7 Upgrade Paths – RC to RTM Jump Not Supported