There's a program everyone should have, called speccy, made by priform. Free download. Tells you everything you need to know about your computer. Figure out what your GPU in each computer is, than punch them into
http://www.videocardbenchmark.net/ to compare. Its very possible your laptop may have a better gpu but a weaker CPU. Good news, in that case, is that you can upgrade a desktop's GPU.
Also, reason #952 why AMD/ATI chips suck: incompatibility with basic standards.
64794.
And since a desktop ram stick is physically larger than a laptop RAM stick, then its
pretty obvious</I] that if a laptop stick can be 8gb, then a desktop stick can be too.