Is the AMD64 version also for Intel EM64T?

Total Newby here, my WinXP crashed (for the upteenth time) and we determined it was a hardware failure. Got a new motherboard, processor chip(Intel Core2Duo 6300) and a 300GB Seagate hard drive. We reused the existing RAM memory (DDR 256Mb x2), Graphics card (nVidia MX440), & Sound card but later discovered the cooling fan on the graphics card wasn't spinning, causing it to overheat and fail, leading to a full system crash & reboot. Removing the card and running the native motherboard video solved the problem. A new cooling fan is on order. You see, we thought it was the hard drive dying on us; after rebooting, Windows would run CheckDisk and invariably find bad sectors on the disk (usually cause it was in the middle of reading/writing to disk when it crashed), so we replaced the hard drive with a newer, bigger hard drive. Windows was reinstalled and is currently on my new big drive.

After much stress and fustration, we decided to try a Linux Distros on the 1st original hard drive (Maxtor 50Gb). At 1st we were leaning towards Xandros, but they want money. Then we discovered Ubuntu. So many flavors! Ubuntu, Kubuntu, Xubuntu, Edubuntu! Then there are the different versions, 6.06LTS, 6.10, 7.04. Then we finally have the X86, AMD64, & Sun UltraSPARC. Makes my head spin just thinking about it.

I told you all that to ask this: Which version best suits my configuration? I'm leaning more towards the 6.06LTS for the long term support offered by Canonical, 'cause I am still new to this whole Linux experience, and I might need help later. Especially when I recieve my graphics fan & reinstall my graphics card.

A friend gave me a disk of Ubuntu 6.06 that I test drove for a few days using the LiveCD option before I went ahead and installed it on my smaller drive. It runs a bit slower than I would like, and I am not sure if it is because of the lack of a video card or because it was written for the older 32 bit archetecture, and only accessing 1/2 of the chip in single processor mode. I'm going to download the 3 remaining versions and test them out to see which one I like most, but my main concern is the 64 bit question. Is the AMD64 install compatable for the Intel DualCore chip? It's 64 bit, but it's also Intel. I'm not sure, any of you had experience with this? I want to maximize my performance out of my computer.

Thank you in advance for answering my question.