I ran IDES on my Dual Core 2.2 Ghz notebook and it worked fine.
Both systems are over kill as far as the CPU goes for IDES (full SAP with users is another story!)
If you want to run BI I'd suggest bumping up the ram to 6gb or 8gb
My Development system is running the full version of SAP NW 7.0 on a Q9400 @2.66 Ghz with 8gb of RAM
That is a HP workstation PC, not a server using Server 2003 64 bit and Oracle 10