Very confused about memory options on XPS 710

UPDATE:  I just had the Corsair TWIN2X4096-6400C5 memory package overnighted to my house and when I plug them in, my computer will not make it past the BIOS screen.  I can plug back in the OEM memory and it boots fine (other than giving me a warning that it did not make it last time.)

I am EXTREMELY disappointed in this whole experience with what is supposed to be a premiere DELL computer...

So consider this fair warning, if you are going to try the TWIN2X4096-6400C5 memory, use free shipping because there is a fair chance you'll eat the shipping when you send it back...

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I have 2 Gb of 5300 installed in my XPS 710 and the crucial website tells me that I can run 6400 ram on my machine.  The crucial website also says that I must buy 4 x 1Gb RAM for my machine and seems to indicate that I cannot use 2 x 2Gb RAM.  Dell seems to suggest that I CAN use 2 x 2Gb on this machine.

More frustrating is that the more I learn about my XPS 710, the more I feel like Dell has crippled my hardware.  Apparently this board runs memory at 1.8 volts and that seems to limit me to "value" (read, "slow") memory instead of faster "gaming" memory which seems to need 1.9-2.2 volts to run lower latencies.

From what I can tell, Dell has limited my BIOS so that there is no way to increase memory voltage to take advantage of these faster memory chips. I am VERY DISAPPOINTED in my options right now and I will SERIOUSLY look at other brands when it comes time to get a new computer.  I've had DELL computers for the past 10+ years and have spends tens of thousands of dollars personally with DELL and have directed many other people to Dell over the years.  This single computer is making me rethink that.

Anyway, on to the point.  What is the best RAM that I can put in this machine that will work?  I plan to put 4 Gb of RAM and would like to go with 6400 RAM.  Is there a KNOWN to work high-speed 6400 chip that will work?  Can I use 2 x 2Gb or is the crucial site correct in saying that I must go with 4 x 1Gb?  Any help would be greatly appreciated. 

I thought that I had this worked out the other day, but then the voltage issue came up and threw me back to square one.  I cannot begin to express how disappointed I am with the limitations on this computer.  I am not an "overclocker" by nature, but this computer has never been the speed demon that I thought I was getting (and paid for) when I replaced my previous XPS computer.  Now I know some of the reasons why...

-Tom Steele