RAM and VGA question !!!

Hi friends from notebook review...
i have to question consider about RAM and VGA...

About RAM :
I have 6GB RAM on my Alienware m17x (1X 4GB + 1x 2GB)
But, my friends said that its weird to have a 6gb with option of (1X 4GB + 1x 2GB). He said that i should have an identical RAM such as (2x 3 GB) or (2 X 4GB). I dont understand why he said like that. Can somebody explain it to me.
and whats the different between 6GB (1X 4GB + 1x 2GB) and 6GB (1X 4GB + 1x 2GB) in performance...???

About VGA :
I Have Crossfire Dual HD ATI 5870 on my alienware m17x...
My question is does anyone ever use it on CAD programs ?
and how does it works on CAD programs..?
I mean the VGA performance on CAD programs.
cause i heard that it cant be use to render a CAD program or running a CAD program. Does it true..??

And for info, i used 920XM. does the processor also concern the performance of CAD program ?

and One more things is there big difference in QUADRO and 5870 in CAD program ...??
can QUADRO do CAD programs and playing games greatly ?
can ATI (5870) DO CAD programs ?

Thanks...

 

It is preferred to run RAM modules in same sized pairs (ie. two 2GB sticks = 4GB or two 4GB sticks= 8GB) although to be honesty doesn't really make much difference in performance.

Quadro cards should be slightly better for CAD but not a great deal of difference, depends if you use your M17x alot for CAD.

I have toyed with the idea of installing Solidworks 2010 on mine to see how it runs.

 

there was a mod where you can install the Firepro Drivers for the 5870 and that would give you a boost in the CAD department.

Also your friend was talking about single channel vs dual channel while there is some improvement it is not noticeable and they do not make 2 x 3 GB sticks.

See the major differences between quadro and the gaming version is the driver support. Like I mentioned above though there was a mod to install the Firepro drivers which is ATI's version of Quadro.