if the rar files are on the same disk simply move them. Ive just run a test I had 2 dvd archives on one drive I moved one to desktop ( a different physical drive) and run quickpar both archives had broken rars and I run repair on the 2 with no impact on either. Then I run IE off the c: obviously where the desktop is and the impact was huge ( same disk) one archive was more broken than the other so as one was still repairing I extracted the fixed one to yet another hard drive again with no impact. So if you have the drives you can perform the tasks
Who said anything about using this for average Joe in the street??? how many average Joes buy and use well performance machines? not many
---------- Post added at 01:34 ---------- Previous post was at 01:24 ----------
ok to further the test I just run 2 x quickpar running rar repair and 1 instance of winrar extracting a large archive all on different disks all running as fast as if alone and running cpu resources at 95% again the only thing that lagged the system is running a second app off one of the disks so in theory with 4 cores and enough drives I could run 6 instances 3 of each on 4 core without impact so I think there you go