Core 2 Duo 64-bit Compiling?

[Mr. The Guy]

I have a Intel(R) Celeron(R) CPU 2.80GHz w/EHT64 in my desktop. When I compiled Gentoo with x86_64-pc-linux-gnu and -march=nocona instead of Pentium 4 flags, I got about a 20-25% improvement in ogg encoding speed and everything else seems ALOT faster.
Am I wrong in understanding that the Core 2 Duo will allow for 64-bit compiling too, or is it just the processor that is 64-bit and the existing boards don't support it? Do I have to wait for Santa Rosa and a new mainboard to get real benefit from the 64-bit capabilities of the Core 2 Duo?
Is the 3GB RAM limitation a Windows-only limitation? Will Linux let me use 4GB of RAM if and when I ever upgrade? I was planning to get a slow, small HD and 512MB RAM in whatever model I decide to get, and then upgrade to a 7200 rpm perpendicular drive when they hit 200GB or more.
My last notebook is now 6 years old and still works, and I would like to get 6 years out of a Thinkpad so if I have to wait 'til spring it's no big deal, but I thought I could upgrade now...

[tomh009]

I have a Intel(R) Celeron(R) CPU 2.80GHz w/EHT64 in my desktop. When I compiled Gentoo with x86_64-pc-linux-gnu and -march=nocona instead of Pentium 4 flags, I got about a 20-25% improvement in ogg encoding speed and everything else seems ALOT faster.
Am I wrong in understanding that the Core 2 Duo will allow for 64-bit compiling too, or is it just the processor that is 64-bit and the existing boards don't support it? Do I have to wait for Santa Rosa and a new mainboard to get real benefit from the 64-bit capabilities of the Core 2 Duo?
Is the 3GB RAM limitation a Windows-only limitation? Will Linux let me use 4GB of RAM if and when I ever upgrade? I was planning to get a slow, small HD and 512MB RAM in whatever model I decide to get, and then upgrade to a 7200 rpm perpendicular drive when they hit 200GB or more.
My last notebook is now 6 years old and still works, and I would like to get 6 years out of a Thinkpad so if I have to wait 'til spring it's no big deal, but I thought I could upgrade now...

We're trying to figure this out in another thread in another forum, too. Intel's info for Merom (the current Core 2 Duo) and Napa64 (the Centrino Duo platform update for Core 2 Duo) indicates "Intel 64" support but then there are people saying that Santa Rosa is needed. Someone with a Core 2 Duo notebook needs to try this, I think ...

http://forum.thinkpads.com/viewtopic.php?t=32273

That said, I run a number of Opteron servers with FreeBSD/AMD64. 64-bit doesn't really gain you much in small apps, but it gives you acess to lots of memory, and in large apps (databases, image processing, busy application servers) that can make a huge difference.

[Mr. The Guy]

64-bit doesn't really gain you much in small apps, but it gives you acess to lots of memory, and in large apps (databases, image processing, busy application servers) that can make a huge difference.

I bought my desktop CPU at a time I had no money and my previous CPU had to be replaced, so I just bought the cheapest board and CPU combo I could find and set Pentium 4 flags without even checking. When I had some time, I did read up and discovered the 64 bit support and re-compiled. The only app I run where I could see measureable differences was in flac to ogg encoding which went from between 9 to 11.5X to between 12.5 and 14X. All other speed increase perceptions are subjective.
I just did a search on the Gentoo forums and no one there seems to know either and a cflags page http://gentoo-wiki.com/Safe_Cflags#Inte ... C_Merom.29 contains a Merom WARNING, so it looks like anyone who actually knows is not talking (probably to keep the phone calls from Windows users to a minimum), or it doesn't, which is what I'm beginning to suspect.
A cat /proc/cpuinfo would probably help us all out...
Is anyone 64-bit chipset and CPU-ready in a laptop?

[Mr. The Guy]

We're trying to figure this out in another thread in another forum, too.
http://forum.thinkpads.com/viewtopic.php?t=32273

This thread has confirmed 64-bit is supported, but the RAM issue was not addressed. When I configured a z61t, it said it was a limitation due to 32-bit, but the model I configured was 64-bit.
I was going to get 1024MB RAM, but if I can get 4GB addressed, I'll have to start w/512 or get one 2GB stick...