Build your own. Problem solved. If you buy one, regardless of brand name (alienware, for example, is still just a Dell.) you are likely to get a box of refurbished parts which will probably only function just over your warranty period.
My last experience with Dell involved a failed I/O panel, a failed SM Bus, failed graphics card, failed PSU, and a failed Hard drive within the span of about 3 years or so.
Also, gaming on a Laptop?
But yeah, to be helpful, I will say that I run an 2.6 GHz Dual-Core 5000 Series AMD Athlon, with 2 Gigs of memory and an Asus EN9800GT Matrix (nVIDIA).
These are far from cutting edge or even modern, but I run CiV just fine, apart from the interturns being a bit slow in the modern era. I've made extensive use of OS Tweaks and configuration tricks to keep my machine running fine, but it's about that time to build a new one.