Can WinXP (x86) see more than 2GB of ram, or not?

  • Thread starter Thread starter mjs
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Carl said:
32-bit Windows will be able to use (4 GiB - whatever is needed for
hardware addressing). An individual application gets to use up to 2
GiB. There are exceptions to this, but I'm not fully versed on the
details and hence will keep my mouth shut.
Click to expand...

You are confusing Virtual Address Space with RAM, the two are not the
same at all.

John
 
John John said:
What is it that you did not understand in the other replies in your
thread? Windows XP can only address (supply addresses) for 4GB of
memory. Memory does not mean RAM only, it means memory for everything in
the computer. Practically all the devices need memory addresses, if you
have 4gb of RAM in the machine and if the video card has 512MB you need to
supply addresses for 4.5GB or memory, but XP can only address 4GB, so it
will supply the addresses to the video card and that will reduce the
available addresses for RAM to 3.5GB, it has to cut the addresses
somewhere and the only place it can cut without crippling devices is by
cutting available addresses for the RAM.

We don't know what the memory requirements for your devices are, but we do
know that they will receive addresses before the RAM and that means that
YOU WILL NOT BE ABLE TO USE ALL 4GB OF RAM. Based on common knowledge and
rules of thumb all we can say that you will not be able to use the last
500 to 1250MB of RAM in the machine. If you want to know the approximate
exact amount look in the Device Manager and show resources by connection.
Get yourself a hexadecimal converter and figure out the memory resources
for the devices and subtract it from 4GB and you will know approximately
how much of your RAM will be usable.

John
Click to expand...

I apologize if I'm being a bit too direct here, but I keep reading this over
and over again and what it seems to boil down to is something that can be
summed up a lot more simply than the pages and pages of replies in this
thread describe : "The amount of RAM used is however many you have installed
minus whatever your graphic card is using."

That's the bottom line, isn't it? In practice, if not in theory. Then why
not just say THAT? I mean, everyone keeps talking about "other things" that
could be getting into that ram space, but the BIOS is insignificant in
size -- as is just about everything else with the possible exception of the
video card.

I've said time and time again what my hardware is. Why is it so hard to
concede that in this very specific scenario, I'd have A LOT to gain by
installing 4GB of ram?

The applications NEED the ram. The video card is a mere 128mb model. What
other factors exist to scare me out of installing more than 2GB of ram? From
all accounts, it's a no-brainer in the OP's (my) situation : INSTALL 4GB OF
RAM.

Or am I STILL missing something in this debate?
 
mjs said:
But will it be able to use more than 2GB?

Seems everyone here is comparing apples with oranges. On one side, people
are saying I WILL be able to use more than 2GB of ram. On the other, they're
saying I WON'T be able to use all 4GB.

Something tells me the truth lies somewhere in-between. That BOTH sides are
right. That I will never be able to use 4GB of ram on WinXP x86, but that I
can probably see and use 3GB -- especially if I'm only running a single
128mb 6600GT video card (Asus EN6600GT, to be more precise).

The apps I use make high use of ram, where even the slightest increase in
performance will be a huge relief. So if adding 2 more sticks of ram (4GB
total) will allow me to use only 3.5GB, then I will add 2 more GB. Yes, that
half-GB is something I'm willing to pay $50 for.

If, on the other hand, my limit is more likely to be 3GB, then I will buy a
single stick and add it.

What I HAVEN'T seen in these exchanges is anyone inferring that 2GB is my
limit. It seems that at the very LEAST, I could add a 3rd stick. Right?

The question now becomes... do I add a 4th?
Click to expand...
I currently have 3 GB of RAM installed in my computer, 2 x 512 MB and 2
x 1GB, and have times where XP has allocated over 2.5 GB of it. I
normally have around 1.5 GB of memory committed.
 
mjs said:
I am running WinXP Pro SP2 on an Asus A8N-SLI Deluxe motherboard (AMD64).

I've been thinking of upgrading my RAM to 4GB (from 2GB) but I keep
hearing conflicting stories about WinXP's ability (or lack of it) to
recognize all of it when running at 32 bits.

I'd like to get the truth straight from the horse's mouth - if I add 2
more sticks of ram in there (4GB total), will my system be able to see all
4 GB?

Yes or no?

Let's put this debate to rest once and for all.
Click to expand...
It has already been put to bed numerous times.
Jim
 
mjs said:
But will it be able to use more than 2GB?
Click to expand...

Yes. It will use as much as it can allocate addresses to.
Seems everyone here is comparing apples with oranges. On one side, people
are saying I WILL be able to use more than 2GB of ram. On the other, they're
saying I WON'T be able to use all 4GB.
Click to expand...

There may be confusion between physical RAM and the 4GB virtual
address space given to each process. The virtual space is normally
divided half-and-half between the OS and the process. the /3GB switch
confines the OS to 1GB, leaving 3GB virtual memory for the app. That
constrains the OS, and should be done only in rare cases. /3GB will
have NO effect on physical RAM.

Physical RAM, at any time, will have pieces of *many* virtual address
spaces in it. One of the most important things the OS does is to keep
track of this, and figure out what to write to the swap file when a
process needs to allocate more space or read a page from the swap
file.
 
mjs said:
I apologize if I'm being a bit too direct here, but I keep reading this over
and over again and what it seems to boil down to is something that can be
summed up a lot more simply than the pages and pages of replies in this
thread describe : "The amount of RAM used is however many you have installed
minus whatever your graphic card is using."
Click to expand...

Well sure, that is the biggest part of where the lost memory addressing
goes. But then when users come here and tell us that they have no video
card but still cannot use or "see" all the 4GB of RAM aren't you going
to have to explain all of this over again. Won't you have to tell them
about on board video and that their sound card might be using 64MB or
more? And then of course you will still have to explain to some users
why it is that a video card with it's own independent memory can be
"stealing" memory from the RAM. Many will be hard pressed to understand
why they even bothered to buy that expensive video card with 768MB of on
board memory.

John
 
mjs said:
I apologize if I'm being a bit too direct here, but I keep reading this over
and over again and what it seems to boil down to is something that can be
summed up a lot more simply than the pages and pages of replies in this
thread describe : "The amount of RAM used is however many you have installed
minus whatever your graphic card is using."

That's the bottom line, isn't it? In practice, if not in theory. Then why
not just say THAT? I mean, everyone keeps talking about "other things" that
could be getting into that ram space, but the BIOS is insignificant in
size -- as is just about everything else with the possible exception of the
video card.

I've said time and time again what my hardware is. Why is it so hard to
concede that in this very specific scenario, I'd have A LOT to gain by
installing 4GB of ram?

The applications NEED the ram. The video card is a mere 128mb model. What
other factors exist to scare me out of installing more than 2GB of ram? From
all accounts, it's a no-brainer in the OP's (my) situation : INSTALL 4GB OF
RAM.

Or am I STILL missing something in this debate?
Click to expand...

Not much as far as a debate. Install 2 more GB of RAM, and accept what
increase you actually get. Simple as that.
 
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