You can run it, but I'd be very, very careful to analyze not only the system hardware, but all your software and all your peripherals as well.  XP64 has very limited driver support - and it's a past-tense OS, so what's not there as far as drivers never will be (32-bit drivers won't work, and Vista 64-bit drivers are not supported).

Software will larglely work even if 32-bit.

Drivers that are not 32-bit will NOT work with 64-bit XP, nor will 64-bit Vista drivers work with XP. 

64-bit XP wasn't very popular or widely supported - if you really want to run a 64-bit OS, you'd be better off with 64-bit Vista.

There are some 4G soDIMMs but expect them to be very pricey - $800+ for each.

ejn63,

Thank you for your reply.

Well I went online and according to Intel and Microsoft 32-bit software is suppose to be able to work. Also, if I install Vista 64-bit won't 32 bit applications still work? I think they are suppose to.

Do you have any literature that I can read about all this stuff?

Also, according to this link, the M6300 can handle up to 8 GB of Memory. Is that true. Where can I get 4 GB sticks? I don't see any on Dell's website. 

Link: 

http://www1.ca.dell.com/content/products/productdetails.aspx/precn_m6300?c=ca&l=en&s=biz&cs=calca1

Andrew 

I am running Vista 64bit and just ordered 2 x 4G Kingston KTDINSP6000B4G chips for $450 each from http://www.directdial.com.  If you google the part number you will see them as cheap as $437.

I got the M6300 in order to run 4 32bit operating systems (2 Win2K3 & 2 WinXP) on top of VMWare Workstation 6.0 for client demos.

So far working like a charm, extra memory should arrive tomorow.