Comparing Xeon vs Regular Intel Procs

[Phylum]

Hi all. Let me start off by humbling myself as I'm no PC guru. I've tried searching on google for this answer, but have been unsuccessful. I also thank you for taking the time to check this out.

I'm looking at picking up a dual Quad Core Xeon system however I have a few concerns about performance and compatibility. I'm hoping someone could help me get some crucial questions answered:

What is the performance difference between a Quad Core Xeon and a Core 2 Quad of nearly equivalent speed? (e.g.: 1.6 or 2.0)
Is there a big difference or is it marginal?

Seeing as this machine will be my new desktop replacement running, ideally XP Pro, Linux and Windows Vista Ultimate, I'd like something rather robust. I will primarily be running Linux with Windows in a VM, but I'd like the option to dual/triple boot. And yes, I do plan on playing some games every now and then: mostly GRAW, StarCraft and Supreme Commander. (I've got a load of older games that I'm sure will run fine.)

[Note: One concern I have is whether or not XP Pro and Vista Ultimate support dual quad procs, but I'll look into that on my own. If you have any experience in this area, its appreciated, but please understand that I have not yet done enough research in this area.]

My primary focus here is getting more information on whether or not there is a significantly noticeable performance increase between a Quad Core Xeon and Core 2 Quad.

I thank you for at least reviewing this. I've not found any charts or indication anywhere of this. If you have a link, please let me know I would greatly appreciate it.

Thanks

PS - If you're asking yourself "why dual quad xeon?" Well, I came across what appears to be a REAL deal, and I could use something beefy.

[Apoptosis]

What is the performance difference between a Quad Core Xeon and a Core 2 Quad of nearly equivalent speed? (e.g.: 1.6 or 2.0)
Is there a big difference or is it marginal?

What benchmark are you interested in? I have a dual quad-core XEON system and a sigle Core 2 Quad QX6700 on the test bench right now.

[Phylum]

Thank you for replying to this post.

Since its different hardware, I guess its hard to tell the difference 'in general' system performance. How do Quake IV and UT 3 run? (If you don't have the ability to test that, what about some other 'modern' games like call of duty 2 etc)
What OS' and How much ram?
FYI - The server proc choices I'm considering is the 5300 series, so something between a 5310 and 5335. And as for motherboard, its a Dell server, SC1430, so whatever they chuck in there.
I plan to load it up with 4-5GB of memory to start and maybe go up to 8 as needed for my VM needs.

In your opinion, which system seems to perform the best for gaming and general operation? (read:What's might be or is more advantageous for general and gaming purposes?)
In your opinion, should I go with a dual quad xeon or maybe a core 2 quad (assuming there isn't that much of a price gap)?

Thank you again, I greatly appreciate the feedback.

[Apoptosis]

I'll play around with it tomorrow... I didn't see it's almost 9pm!