If you use DVDShrink, or similar program, in one step ripping and transcoding, it is always hard to judge where time is spent: ripping or transcoding. So if you rip first to hard drive, then it doesn't really matter if the source DVD is NEC 3500 or another brand. You can compare what speed other users get when ripping, or read the reviews from couple of months ago. Here most likely that even less powerfull CPU will get the job done as fast as the drive can read, as CPU utilization might be well under 100%. You can see some numbers like so if you use Nero CD-DVD Speed test program, or look at Task Manager display while speed testing.
As for transcoding/encoding stuff, as was mentioned above, more is all you need
more CPU mainly. When you transcode just watch the CPU % utilization, if close to 100% it means more CPU is needed. As simple as that.