I don't think you need the fastest or most modern PC for ripping. I use dBPoweramp and a dual CPU Xeon 3.6GHz (Nocono processor) with an 800 MHz FSB and Win XP.
The biggest factor IMHO is the CDROM/DVD drive. I use Plextor drives with an error detecting ROM. This DVD drive can detect both C1 and C2 errors. My two CPUs are hyperthreaded for a total of four logical CPUs, and dBpoweramp divides many of the tasks between all four CPUs. The ripping speed is determined by the actual ripping conditions on the disc. Some rips run at > 35x, but others run much slower. Its unclear to me why the speeds vary that much, as I see a large speed variation even between immaculately clean discs.
The Secure Rip function is great but I have run into situations where my particular album was not in the secure rip database. I have also run into one or two albums where dBpoweramp refused to read a disc (perhaps due to some form of copy protection), although my CD player and Plextor will still play the music through the PC.