Welcome to new JJMPF - JJMehta Photography Forum
I wonder my lappy running 32bit WinXP over Core 2 Duo at 2GHz with 2GB DDR2 667MHz RAM and on board intel graphics processes RAW with DPP as smooth as butter, no hiccups or anything. I believe there is no point in going for Quad Core or costly SSD's just for processing RAW files.The fact with win7 is that around 1GB of RAM will be used for running the OS itself.
It's not that I have no other work and keep on tinkering with PC but the main problem happens due to bloated registry if you know how to safely clean it then may be reinstall is not needed. De-fragmentation takes time so one should start late night and leave it running overnight, Also if you set the tasks like weekly / monthly defragmentation the situation never arrives.Reinstall does not necessarily need complete backup anyway. You can just install OS copy on a different partition.