How long is forever?
CCE doesn't support HT or SSE3, surprizingly enough. I use an AMD64 3000+ and doing a 9 pass encode (I tested a few different passes for speed) took about 13 hours in one pass mode. I have SATA hardrives and 1GB of ram.
Supposedly, the SSE2 commands that Intel chips have are slightly faster than those in the AMD64. If the speed is really bothering you, you could try the RB-farm or whatever its called. I don't recall if it works with this newest version though.
Also, remember that if you encode anymore than 5 or 6 passes (most say 4), you're pretty much just wasting time.
Here's the CCE CPU compatibility site btw: