Intel(R) Pentium(R) 4 CPU 3 00GHz maximum memory

As it is only a 32 bit processor it can only support a 32 bit OS which can only support a limited number of addresses which restricts memory available. The board that CPU is running on likely doesnt support that much though, check the board specs as those are likely the same or lower.

The processor isnt what limits the RAM, its the motherboards space, and the operating systems ability to address all of the memory.

Like jsc said, it sounds like HW, wikipedia can answer lots of these questions for you.
 

Vampyrbyte

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the CPU's Architecture is the limiting factor with the memory.
I took the liberty of looking up ever 3Ghz, and 3.06Ghz Pentium IV for OP.

The following are not EM64T processors, and thus will only support memory up to the addressible ammount of 32 bits of memory space. Which works out as most of us know at about the 3.5GB Mark:


Mobile Intel® Pentium® 4 Processor 532 supporting HT Technology (1M Cache, 3.06 GHz, 533 MHz FSB)


Mobile Intel® Pentium® 4 Processor supporting HT Technology 3.06 GHz, 512K Cache, 533 MHz FSB

Intel® Pentium® 4 Processor supporting HT Technology 3.00 GHz, 1M Cache, 800 MHz FSB

Intel® Pentium® 4 Processor 530/530J supporting HT Technology (1M Cache, 3.00 GHz, 800 MHz FSB)

The following Pentium 4 Processors will support just about any ammout of RAM you can throw at it, as they are EM64T compatible processors. However you will need to be using a 64bit OS, such as the x64 editions of Windows XP, Vista or 7. or any x64 Linux Distro (These are often labled AMD64, dont be confused, AMD64 and EM64T are for all intents and purposes one and the same) to access any more than 3.5GB of memory:

Intel® Pentium® 4 Processor 631 supporting HT Technology (2M Cache, 3.00 GHz, 800 MHz FSB)

Intel® Pentium® 4 Processor 630 supporting HT Technology (2M Cache, 3.00 GHz, 800 MHz FSB)

Intel® Pentium® 4 Processor 531 supporting HT Technology (1M Cache, 3.00 GHz, 800 MHz FSB)

On a note, I dont know if this is an exhautive list, i took it from Intels website, so if im wrong, blame Intel :p.

You can check however what your processor is, and if it supports EM64T by using a simple system information tool such as CPU-Z.
 

Crashman

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Typically it's the chipset that limits the amount of memory that can be installed per slot, and the board that limits how many modules can be installed. You're often limited to 4GB simply because the old modules max out at 1GB and the board has four slots.
 

Vampyrbyte

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That will be the case for the processors supporting EM64T. But with the processors listed not supporting EM64T, presuming a fairly recent motherboard ofcourse, the limiting factor will be the CPU itself.
 
Its both. You need a CPU that can handle the 64bit wide instructions, and the memory controller needs to handle it as well. This isn't a problem today as the memory controller is on the CPU, but it could have been an issue back then. And as crash correctly pointed out, you'd need either dense enough memory modules or enough slots to get above 4GBs.
 

Crashman

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Former Staff

I guess I'm the only one who remembers that Intel used to place artificial limits on the amount of memory addressable by low-cost chipsets, a practice that probably ended during (not before) the Netburst era.

But with the chipset supporting eight banks of RAM at a maximum of 512MB per bank, it would be impossible to add more slots.

And then VampyrByte's comment on CPU's must be completely wrong, because putting an EMT64-enhanced Netburst processor into a DDR1 motherboard still only takes you to the 4.0 GB limit of...drumroll please...the chipset.

That is, unless you have a server board...with a different CHIPSET that supports additional memory slots :)

VampyrByte, the limit had nothing to do with the CPU until the memory controller was moved to the CPU.

Reading material for VampyrByte

http://en.wikipedia.org/wiki/Physical_Address_Extension

His processor supports at least 64GB of RAM. If you want to delete all your comments about the CPU limit, I can delete all my counterclaims and we can both come out looking helpful rather than argumentative. :)
 

Vampyrbyte

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Not at all, I completly forgot about PAE, which isnt suprising seeing how the limits you mentioned placed on intel chipsets makes it largely irrlevant.

I may from this get a non-EM64T processor and try it in my current board which supports 8GB of RAM, and do some practical investigation into how this works compared to a 64bit system.
 

Crashman

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Former Staff


Great, make sure you use an operating system and applications that can take advantage of PAE :p I think Windows Server 2003 would work, but as for the applications...wait, THG has an article on how to modify some programs with a "large" command or something to overcome what is it...a 2GB limitation?