In
Ken is right; you should have no problems. In fact, depending on the mobo
and setup, you might not even be able to use a 2 + 1 GB mix of RAM modules.
Many systems require them to be inserted in pairs, and then go even farther
and insist that they be the same size for each module in the pair, so a 2 +
1 might be disallowed anyway
..
Further, if say, you have 4 memory slots and two 2Gig modules, the
modules may be requied to occuply slots 0 and 2 only. Or slot 0 only if a 4
GB module is allowed; often they are not. Slot 0 must always be occupied.
It sounds a lot worse in words than it really is. All it really means is,
be sure to read the documentation that explains how RAM expansion is
accomplished for your specific mobo if you aren't already certain. For
instance on my Dell T3400 I cannot use any RAM module greater than 2 GB
each. If there is to be more than one RAM module, they must be installed in
pairs 0, 2 and then 1,3, plus each module of each pair must be the same
size.
They can vary in speed capabilities, but the entire RAM complement will
run at the slowest speed of the slowest module in the set/s.
The
Yes, that's no problem.
But bear in mind that "XP can only use 3 GB of RAM" is not
completely accurate. Here's the correct info:
It's completely accurate enough for the purpose of the querant and all
you've really done here is provided information that could "confuse the
issue with facts".
All 32-bit client versions of Windows (not just Vista/XP/7)
have a 4GB address space (64-bit versions can use much
more). That's the theoretical upper limit beyond which you
can not go.
"Theoretical"?? Hardly. 4 GB or however you want to count it, is EXACTLY
the number of address spaces available. It's not theoretic; it's very real
and the laws of physics makes sure it remains that way.
But you can't use the entire 4GB of address space.
Wrong: You CAN and DO use the entire 4 GB of address space. There is no
"wasted" RAM, this time in theory, because some addresses, though they
exist, may never be used in every machine although they are still assigned,
and there are a few used for software setups too, plus some of the BIOS
needs.
Even
though you have a 4GB address space, you can only use
*around* 3.1GB of RAM. That's because some of that space is
used by hardware and is not available to the operating
system and applications.
Hardware is NOT the only address sets that are assigned by the system when
it starts up.
The amount you can use varies, but is more likely to be in the 3.2 to 3.7
area for most retail machines sold today.
It isn't the "amount you can use", it's the amount that is LEFT available.
Unless you do something silly, you WILL use it, not "can" use it.
depending on what hardware you have installed, but can
range from as little as 2GB to as much as 3.5GB. It's
usually around
3.1GB.
Very, very few people, if any, will ever see 2 Gig used by system hardware
on a standard XP desktop machine. 2 GB however is often considered the
"sweet spot" or "point where diminishing returns" will soon occur.
More accurately stated, the system first assigns the system addresses from
the top of the 4 GB of address space downward. Since an address cannot be
used twice, those addresses are NOT available any longer to be used for
anything else. Whatever is left after this assignment set is completed is
what you can have for actual Random Access Memory addressing.
If you find you only have 2 GB of RAM available when you install 4,
you're either not here asking these questions because you already know more
than most people here, OR more likely you have a physical problem with your
hardware. RAM or its support cktry has a problem, is mismatched, mis-setup,
or some other hardware issue is going on. In fact, if you see less than 3 GB
available when you have 4 installed, you should still make certain you know
why or you probably wouldn't be the type of person who would need this
newsgroup.
Note that the hardware is using the address *space*, not
No, it's using the "ADDRESS", of which there are 4GB of separately
addressable locations in the RAM modules.
the actual RAM itself. If you have a greater amount of RAM,
the rest of the RAM goes unused because there is no address
space to map it to.
More accurately, the addresses are already used and thus cannot be used to
address anything else.
And we won't even think of discussing RAM Extenders to go beyond 4 GB on an
XP machine although they are available as specialty setups.
If you're going to try to explain things, at least try to be accurate about
them. I'm no expert or technical writer, but your post gave me a couple of
completely errant pieces of advice.
HTH,
Twayne`