yes,A million of difference!hehe, Your comparing a dual core with a Quady..
When ,on dual core:
and less perfomance
For a Quad core
high cache than the dual core
more and more perfomance than a dual core,
If u are buying a alienware lap with dualcore proceesor,U willnot be able to play games as ur dual core will bottleneck the gfx card and all other hardware!
So buy an hp or dell with dual core or
An Alienware with Quad core