I have a dual-CPU system and dual-boot between Win98se and Win2k Pro. Windows 98 just ignores the second CPU without hiccups. Are you a massively multi-tasking user, or use Photoshop or Maya for creating large graphics files or 3-D modeling? Do you use other programs that are multi-thread enabled? If so, you might do well to build a dual-CPU system running under Win2k Pro. And, if you play a lot of computer games, then Win98se is nice to have to make sure those games will run correctly. Some people have great luck getting games to run in Win2K, but I am not one of them. If it's only for playing games, don't bother with a dual-CPU system. Only Quake3 claims to support dual-CPU systems, and I've heard it doesn't do all that good of a job at it. So, if it's just games, or internet surfing, or word processing, build a single CPU system and use the money you'd have spent on a more expensive motherboard & 2nd CPU to get extra RAM, or a killer graphics card, or whatever.