T61p, can it see > 3GB?

Hi,
I can't find the search feature, please excuse me if I'm repeating a question.

My T61P running XP can't see more than 3GB ram out of the 4GB.
I have an HP laptop running XP and it can see 3.7GB out of 4GB.

Is there a driver or a kick in the head I can give the T61 to make it see more? I run Virtual machines and an extra 500MB would come in handy.

Cheers

 

No, what you see is the max youll get. Thats the 32bit limitation.

 

You are running into a hardware limitation that cannot be passed. The laptop needs to use 1GB of address space for all the hardware, leaving just 3GB available for RAM. Only moving to a 64bit OS will get you more than 3GB.

The HP probably does not have as much hardware, which is why it sees more RAM.

 

You need a 64bit OS to recognize anything above 3gb of RAM.

 

Ya, I was reading about the HW limitation and just like you guys said, but how is the HP seeing 3.37 (sorry I put 3.7 in the original post).

 

Different hardware and mapping design. HP just manages to squeeze out more memory in this case. It's not usually a big deal because if you want the full 4GB to be user-addressable, you should be using a 64-bit OS anyway.

 

I wish I could. I tried it and I found a lot of my 32bit proggies wouldn't run, think like landscape design which cost me good money.
Now I'm wondering, is there a compatibility mode that would allow me to run these apps in a forced 32bit space?

 

The T61p uses a 965 chipset, which unlike all variants of the previous 945 chipset does actually support 4GB of RAM and more (there was an addressing bug in 945 that meant you could only access ~3.3GB with 4Gb installed, regardless of the OS used...)

This is not a limitation, per se, of a 32-bit OS. XP and Vista 32-bit versions, AFAIK only support 4GB of _address space_ - i.e. total addressable memory, including memory on graphics cards and device mapped memory 'steals' even more, so in reality you'll not likely see more than about 3.3GB of usable RAM in this case either.

If you install a 32-bit version of Windows Server 2008 Enterprise or up, for example, you can utilise up to 64GB with PAE enabled (not that I'd expect anybody here to do that - I'm just making the point that you don't _necessarily_ have to use an x64 OS just to address more memory - indeed, PAE is supported in XP and Vista too, but the 'artificial' 4GB limit remains.)

 

If you're running VMs, why not run your 32-bit Windows in a VM?