Windows 7 - Thinking about a huge GPU upgrade

I currently have a Dell XPS 8100 (Upgraded to 750W PSU) with an ATI Radeon 5770. I am considering upgrading to two GPU's (for even more monitors) but I don't have the room. I was looking around and found a thing that gives me 2 more PCI express slots. I'm still a little effy on how it exactly works though. Would there be a PCI express card that is put in my computer that has a cable leading to the port expander? I'm also not quite sure how 2 GPU's would work. I know its possible, but do both GPU's have to be the same model or something?

If there is better hard ware (or cheaper) please tell me, all is appreciated! Thanks!

Here is the PCI express thing: Amazon.com: StarTech.com PCI Express to 4 Slot PCI Expansion System PEX2PCI4 (Black): Electronics
(I might have to get this depending on the size of the GPU) http://www.amazon.com/Express-2PCIE-.../dp/B002I9SK5S

And here is my current GPU (I will probably get another to put int he PCI express thing) Amazon.com: XFX Radeon HD 5770 1GB DDR5 PCIE Graphics Card HD577AZNFC: Electronics

That is not going to work for you unless you want to add some PCI cards.
Your card supports 3 screens, how many more screens did you want to add?
If you want to just add screens, then you can add any card you want, doesn't have to match the one you have.
you only need matching cards if you want to run Crossfire or SLI, which improves gaming performance on 1 screen, or on an eyfinity/surround group.

Assuming the case for your Dell can take a full size ATX motherboard, a new motherboard with 2 PCI-E x16 slots would much more sense than that external device. If fact you could build a decent computer with the required number of slots for what one of those external devices costs (~$500.00).

Something like this,

Newegg.com - ASUS P7P55 LX LGA 1156 Intel P55 ATX Intel Motherboard

would do the job.

I never thought of upgrading the mother board for some reason, but that makes me ask a new question, can I upgrade my motherboard so I can get a Sandy Bridge i7/i7 extreme?

I can't see why you would need more monitors. You could switch out your 5770 with a 5870 and run two or three large 22 inch monitors. The 5870 should stay within your power supply and the card will last for several years.

That doesn't look like it will fit in my case.

Same P55 chipset only a micro ATX board,

Newegg.com - ASUS Maximus III GENE LGA 1156 Intel P55 Micro ATX Intel Motherboard

Am I not seeing something or does that only have 1 Sata port?

EDIT: I was looking around and saw this: http://www.newegg.com/Product/Produc...Tpk=13-131-711
Would that work for me? (I'm not as concerned about 2 GPU now as much as Sandy Bridge i7)

EDIT again: What makes one i7 better than the next? I want to get the best i7 Sandy Bridge with this (excluding extreme, but I might go there). I'm not sure what to look for in a processor to see what makes it better than another.

Crossfire can be a pain with a motherboard with built in PCIE slots....also if you change motherboards your Dell Windows 7 will not work...Also OEM's "sometimes" use a odd ball case, so a ATX standard motherboard may not fit....

I would suggest either a 6950/6970/580 single video card, or a completely new build....Try this siteiBUYPOWER: 2011 Memorial day Specials Play with the configurator...the price updates as you go...Reviews are mixed on their systems, but you can see how far, how much you want to spend can go....