Question : Problem: New Computer Comparision

This is more of an experience type of question and I hope EE doesn't get too mad at this type of question =).

Let me go over what my older computer was running at so you can get an idea of what I would be coming from.

CPU: Pentium 4 - 3.00ghz - HyperThreading
GPU: Radeon 9400 - 256mb
RAM: 1.5gb DDR2
OS: Windows XP Pro SP3

So the computer finally died on me and I've had concerns while shopping for a new computer. First off I've used Windows XP and I know Windows XP. I've tried Windows Vista a long time ago when it first came out and really didn't like it. Being a guy that does gaming I know that some games just don't like Vista and won't run.

So what I was looking at was a pre-built core I7 920 with 6gb of ram. Now I know I need a 64 bit system to be able to use the full amount of ram. Now what is the compatibility with 32bit programs on a 64bit system(wowexec.exe?).

I also heard XP Pro can't handle more than 2 cores while the I7 has 8(HT). Speaking of HyperThreading, how exactly does that affect performance? Does it turn a 3.00ghz hardware processor into 2 virtual 1.50ghz processors. Wouldn't that mean that mean single threaded applications will run rather slow?

So basically I have 4 questions:

1) What kind of performance increase will I notice from my previously stated processor to the core I7 920?

2) How well does Vista 64 run these days, compatibility wise?

3) How exactly does HyperThreading affect single threaded applications? Does it hinder them or does it matter?

4) Without bringing a money factor into things, Would you recommend the core I7 or something else like AMD?

Answer : Problem: New Computer Comparision

q1) Huge differnece

q2) 64 bit vista runs just fine these days, actually it always ran fine, it was just waiting on 3rd parties to create drivers and apps for x64.

q3) hyper threading will not affect single threaded application so it won't matter

q4) Core i7
http://www.anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3448