a dual core processor is going to help if you use your computer for things other than games, browsing and office apps. stuff like video/audio encoding, 3d modeling/rendering, etc. otherwise the end user probably won't notice a difference. we have had the ability to multi-task for years with single-core processors, its called prioritization. CPU time is shared among processes and as long as you're not running two full-time processes you wouldn't give it a second thought. I will say though that if you're the kind of person that unwittingly runs dozens of unnecessary background processes a dual core processor will keep the system from feeling sluggish. but if you run a clean OS with just the background tasks you actually need single core processors will feel just as fast as dual core ones. the limiting factor will usually be hard drive speed anyways in that case, especially if you have less than 1GB of ram.