Will any Pentium4 processor recognize 4G of ram, if the motherboard will populate it?

[sincerequestioner]

The reason I ask this (and I date myself) is the 'good old days' when
64M or 128M of ram was a cutting edge machine. I had a machine that
would only recognize 48M of ram.........forget the processor, etc. but
know it was a compaq.....

any help is greatly appreciated.....

 

[Yousuf Khan]

The reason I ask this (and I date myself) is the 'good old days' when
64M or 128M of ram was a cutting edge machine. I had a machine that
would only recognize 48M of ram.........forget the processor, etc. but
know it was a compaq.....

Pentium 4 actually has 36 address lines, so it should be able to access
upto 16GB of memory, not just 4GB. But that also depends on what chipset
capabilities you have. If the chipset can only address upto 30-bits of
address, then you'll only be able to access 1GB, no matter what your
processor's capabilities are.

Yousuf Khan

 

[Alexander Grigoriev]

The chipset also should be able to relocate part of RAM, to free some of
32-bit space for PCI devices.

 

[Trent]

The reason I ask this (and I date myself) is the 'good old days' when
64M or 128M of ram was a cutting edge machine. I had a machine that
would only recognize 48M of ram.........forget the processor, etc. but
know it was a compaq.....

any help is greatly appreciated.....

Maybe. See http://www.polywell.com/us/support/faq/4GB_Rev1.pdf I've seen a
number of motherboards that only "see" about 3.2GB when 4GB of memory is
installed.

 

[Trent]

Maybe. See http://www.polywell.com/us/support/faq/4GB_Rev1.pdf I've seen a
number of motherboards that only "see" about 3.2GB when 4GB of memory is
installed.

I did a little more digging around, and unless you have a i965 or i975
based motherboard (or server chipset) chances are when you populate your
motherboard with 4GB of memory, you will only realize 3.2GB maximum. You'd
be better off getting (2) 1GB DIMMs and (2) 512MB DIMMs. So it depends on
your chipset, not the CPU.

 

[Tony Hill]

The reason I ask this (and I date myself) is the 'good old days' when
64M or 128M of ram was a cutting edge machine. I had a machine that
would only recognize 48M of ram.........forget the processor, etc. but
know it was a compaq.....

any help is greatly appreciated.....

Yes it will see 4GB. Actually the P4 can handle up to 64GB of memory,
though you would likely hit a motherboard limit before that time.

What's probably a bigger worry though is your operating system. Even
if your hardware will see all 4GB of memory, if you're running a
32-bit operating system you'll be limited to somewhere around 3.2GB of
memory. The processor and motherboard chipset will recognize the full
4GB, but some of that 4GB space needs to be allocated to I/O devices
(PCI devices, hard drive controller, video card, etc.). With a 32-bit
operating system you need to get everything in 4GB, so the top ~800MB
ends up getting allocated to this I/O.

Installing a 64-bit operating system allows your OS to see and use the
full 4GB of memory. As a general rule, if you have more than 2GB or
more of memory, you should really be thinking about a 64-bit OS. Of
course, a potential problem with that is that not all P4 processors
are capable of running a 64-bit OS. It depends on the exact model of
P4 chip that you have.