Vista 32bit VS 64bit???

[SaberX]

Well today i reinstalled Vista Bussness on my buddys T60P.
It got me thinking .....
He has a T60P with C2D 2.0Ghz(t7200),100gig 7200rpm,256meg fireGL video,15.4" WSXGA+,ect.
I made a copy of the restore dvd's. Then in the box when he bought the system came the Vista Bussness DVD.So i used the Vista Bussness dvd(not the new restore dvd's). Everything installed fine ,ran the system update to get all the thinkpad drivers and stuff.After a few hr's with updates all is great.
But i then seen the Vista was the 32bit. I thought that the C2D systems are all 64bit.

Why would IBM put and use a 32bit Vista on a thinkpad that can use 64bit?

Not that he will be buying a new copy of Vista 64 bit but how much diffrence will there be from 32 bit to 64 bit?

Also (i'm gussing NO) but will the OEM# the COA for 32 bit Vista Bussness work on a 64 bit copy of Vista Bussness?

[erik]

driver support for vista x64 is much less than x86 so lenovo doesn't automatically offer vista in 64-bit.

to change an OEM installation to 64-bit, this guide will both help with the process and answer a lot of questions:
http://forum.notebookreview.com/showthread.php?t=144783

[whizkid]

Vista 64-bit will use 8GB of RAM or more. Vista 32-bit will use up to 4GB. In any case, that T60P is limited by hardware to using 3GB in any case, so 32-bit with the better driver support is the far better choice, at least for now.