XP Pro RAM

[Kernel]

If XP can only use 3 GB of RAM, could I install two 2 GB sticks and just let

it choose? The reason being is I'm going to build a new PC and it appears

that 4 GB may be cheaper/easier to find that one 2 GB and one 1 GB.



TIA.

 

[John John - MVP]

Kernel wrote:

> If XP can only use 3 GB of RAM, could I install two 2 GB sticks and just let

> it choose? The reason being is I'm going to build a new PC and it appears

> that 4 GB may be cheaper/easier to find that one 2 GB and one 1 GB.



Sure, no problem at all. Install 4GB and the OS will use what it can,

the rest will just go unused but it won't cause any problems.



John

 

[Kernel]

Thanks for the speedy answer. Now I'm off shopping for some parts...





"John John - MVP" wrote in message

news:O5DUpCQALHA.5808@TK2MSFTNGP02.phx.gbl...

> Kernel wrote:

>> If XP can only use 3 GB of RAM, could I install two 2 GB sticks and just

>> let it choose? The reason being is I'm going to build a new PC and it

>> appears that 4 GB may be cheaper/easier to find that one 2 GB and one 1

>> GB.

>

> Sure, no problem at all. Install 4GB and the OS will use what it can, the

> rest will just go unused but it won't cause any problems.

>

> John

 

[John John - MVP]

You're welcome, have fun shopping.



John



Kernel wrote:

> Thanks for the speedy answer. Now I'm off shopping for some parts...

>

>

> "John John - MVP" wrote in message

> news:O5DUpCQALHA.5808@TK2MSFTNGP02.phx.gbl...

>> Kernel wrote:

>>> If XP can only use 3 GB of RAM, could I install two 2 GB sticks and just

>>> let it choose? The reason being is I'm going to build a new PC and it

>>> appears that 4 GB may be cheaper/easier to find that one 2 GB and one 1

>>> GB.

>> Sure, no problem at all. Install 4GB and the OS will use what it can, the

>> rest will just go unused but it won't cause any problems.

>>

>> John

>

>

 

[Ken Blake, MVP]

On Mon, 31 May 2010 13:28:18 -0700, "Kernel"

wrote:



> If XP can only use 3 GB of RAM, could I install two 2 GB sticks and just let

> it choose? The reason being is I'm going to build a new PC and it appears

> that 4 GB may be cheaper/easier to find that one 2 GB and one 1 GB.







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:



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.



But you can't use the entire 4GB of address space. 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. The amount you can

use varies, 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.



Note that the hardware is using the address *space*, not 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.





--

Ken Blake, Microsoft MVP (Windows Desktop Experience) since 2003

Please Reply to the Newsgroup

 

[Twayne]

In news:mta806tflupt32bhml5phs3jfvqd62k71p@4ax.com,

Ken Blake, MVP typed:

> On Mon, 31 May 2010 13:28:18 -0700, "Kernel"

> wrote:

>

>> If XP can only use 3 GB of RAM, could I install two 2 GB

>> sticks and just let it choose? The reason being is I'm

>> going to build a new PC and it appears that 4 GB may be

>> cheaper/easier to find that one 2 GB and one 1 GB.



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`

 

[VanguardLH]

Kernel wrote:



> John John wrote ...

>

>> Kernel wrote:

>>

>>> If XP can only use 3 GB of RAM, could I install two 2 GB sticks and

>>> just let it choose? The reason being is I'm going to build a new

>>> PC and it appears that 4 GB may be cheaper/easier to find that one

>>> 2 GB and one 1 GB.

>>

>> Sure, no problem at all. Install 4GB and the OS will use what it

>> can, the rest will just go unused but it won't cause any problems.

>

> Thanks for the speedy answer. Now I'm off shopping for some

> parts...



Plus you're likely to retain the dual-channel feature of your memory if

you use matching RAM modules. You lose dual-channel (if your mobo has

it and it is enabled) if you mix a 2GB module with a 1GB module.



From Newegg but without any details of your hardware so I looked up

240-pin DDR2 1066 memory (same Geil brand for all):



4GB (2 x 2GB): $110

http://www.newegg.com/Product/Product.aspx?Item=N82E16820144213



2GB (1 x 2GB): $57

http://www.newegg.com/Product/Product.aspx?Item=N82E16820144359

1GB (1 x 1GB): $30

http://www.newegg.com/Product/Product.aspx?Item=N82E16820231143



So 4GB (2 x 2GB) was $110 while 3GB (1 X 2GB + 1 x 1GB) was $87. Yes,

you would save $23 but you would lose any dual-channel feature. Whether

dual-channel is important depends on if you are currently hitting your

max physical memory. In benchmarks (and not in real use), dual-channel

gives you all of about 7% performance increase, if that. If you're

running out of physical memory, you'll get far more speed increase by

having more memory than for the loss of dual-channel. So 2GB+1GB could

end up boosting the speed of your host even with the loss of dual-

channel mode; however, 2GB+2GB would also give you the speed boost while

retaining dual-channel mode.



http://en.wikipedia.org/wiki/Dual-channel_architecture



Of course, when you later move to a 64-bit OS then you can make use of

that other 1GB of memory. Meanwhile, you could try to use some OS

tweaks, like the one that keeps more of the OS kernel in memory; see:



http://msdn.microsoft.com/en-us/library/ee377084(BTS.10).aspx

http://support.microsoft.com/kb/184419



about DisablePaging Executive. Warning: some drivers actually expect to

get paged out and will fail (crash) if not allowed to do so.



You could also play with the /3GB boot.ini option. The /3GB switch

gives more memory to user process space (i.e., your apps) but is useless

unless those user apps use the IMAGE_FILE_LARGE_ADDRESS_AWARE in the

process header. You probably don't have have any apps that can access

more than 2GB of memory.



http://www.microsoft.com/whdc/system/platform/server/pae/paemem.mspx

http://support.microsoft.com/kb/291988



Have you actually read the manual for your mobo to determine what memory

configurations it will allow?

 

[Kernel]

Thanks. I'm planning on building a new system, Gigabyte AM3 to get SATA 3

and USB 3. But for now I'll be using an extra copy of XP Pro that I have

laying around, hence the 3G RAM question. I'll use two 2 GBs for now then

add more when I upgrade OS.





"Ken Blake, MVP" wrote in message

news:mta806tflupt32bhml5phs3jfvqd62k71p@4ax.com...

> On Mon, 31 May 2010 13:28:18 -0700, "Kernel"

> wrote:

>

>> If XP can only use 3 GB of RAM, could I install two 2 GB sticks and just

>> let

>> it choose? The reason being is I'm going to build a new PC and it

>> appears

>> that 4 GB may be cheaper/easier to find that one 2 GB and one 1 GB.

>

>

>

> 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:

>

> 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.

>

> But you can't use the entire 4GB of address space. 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. The amount you can

> use varies, 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.

>

> Note that the hardware is using the address *space*, not 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.

>

>

> --

> Ken Blake, Microsoft MVP (Windows Desktop Experience) since 2003

> Please Reply to the Newsgroup

 

[Ken Blake, MVP]

On Mon, 31 May 2010 17:29:01 -0700, "Kernel"

wrote:



> Thanks.





You're welcome. Glad to help.







> I'm planning on building a new system, Gigabyte AM3 to get SATA 3

> and USB 3. But for now I'll be using an extra copy of XP Pro that I have

> laying around, hence the 3G RAM question. I'll use two 2 GBs for now then

> add more when I upgrade OS.





Just one more point: How much RAM you need for good performance is

*not* a one-size-fits-all situation. You get good performance if the

amount of RAM you have keeps you from using the page file

significantly, and that depends on what apps you run. Most people

running a typical range of business applications under XP find that

somewhere around 512MB works well, others need more. Almost anyone

will see poor performance with less than 256MB, but few people need as

much as 3GB. Some people, particularly those doing things like editing

large photographic images, can see a performance boost by adding even

more than 512MB--sometimes much more.







> "Ken Blake, MVP" wrote in message

> news:mta806tflupt32bhml5phs3jfvqd62k71p@4ax.com...

> > On Mon, 31 May 2010 13:28:18 -0700, "Kernel"

> > wrote:

> >

> >> If XP can only use 3 GB of RAM, could I install two 2 GB sticks and just

> >> let

> >> it choose? The reason being is I'm going to build a new PC and it

> >> appears

> >> that 4 GB may be cheaper/easier to find that one 2 GB and one 1 GB.

> >

> >

> >

> > 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:

> >

> > 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.

> >

> > But you can't use the entire 4GB of address space. 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. The amount you can

> > use varies, 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.

> >

> > Note that the hardware is using the address *space*, not 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.

> >

> >

> > --

> > Ken Blake, Microsoft MVP (Windows Desktop Experience) since 2003

> > Please Reply to the Newsgroup

>



--

Ken Blake, Microsoft MVP (Windows Desktop Experience) since 2003

Please Reply to the Newsgroup

 

[Kernel]

I'd also like to thank all of the MVPs, and the other guru's, who have

helped soooo many people over the years. I've used the Google Advanced

Search with this NG a zillion times, and always found the answer. In fact I

found a lot of answers and developed a long list of tips that I've saved.

Mr. Ken Blake, and God Rest His Soul Alex Nichol are only two of the

standouts; everyone was always ready to help, even ol' Alias. I don't mean

to try and rank the talent, you are all 'farmers' (a farmer is a person who

is outstanding in his field).



The forums will never be as easy to use, to search, and to get good help as

this service.



Thank you all.





"Ken Blake, MVP" wrote in message

news:bdn8069al33n9mg5kf5cnuek1ubqqap576@4ax.com...

> On Mon, 31 May 2010 17:29:01 -0700, "Kernel"

> wrote:

>

>> Thanks.

>

>

> You're welcome. Glad to help.

>

>

>

>> I'm planning on building a new system, Gigabyte AM3 to get SATA 3

>> and USB 3. But for now I'll be using an extra copy of XP Pro that I have

>> laying around, hence the 3G RAM question. I'll use two 2 GBs for now

>> then

>> add more when I upgrade OS.

>

>

> Just one more point: How much RAM you need for good performance is

> *not* a one-size-fits-all situation. You get good performance if the

> amount of RAM you have keeps you from using the page file

> significantly, and that depends on what apps you run. Most people

> running a typical range of business applications under XP find that

> somewhere around 512MB works well, others need more. Almost anyone

> will see poor performance with less than 256MB, but few people need as

> much as 3GB. Some people, particularly those doing things like editing

> large photographic images, can see a performance boost by adding even

> more than 512MB--sometimes much more.

>

>

>

>> "Ken Blake, MVP" wrote in message

>> news:mta806tflupt32bhml5phs3jfvqd62k71p@4ax.com...

>> > On Mon, 31 May 2010 13:28:18 -0700, "Kernel"

>> > wrote:

>> >

>> >> If XP can only use 3 GB of RAM, could I install two 2 GB sticks and

>> >> just

>> >> let

>> >> it choose? The reason being is I'm going to build a new PC and it

>> >> appears

>> >> that 4 GB may be cheaper/easier to find that one 2 GB and one 1 GB.

>> >

>> >

>> >

>> > 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:

>> >

>> > 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.

>> >

>> > But you can't use the entire 4GB of address space. 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. The amount you can

>> > use varies, 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.

>> >

>> > Note that the hardware is using the address *space*, not 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.

>> >

>> >

>> > --

>> > Ken Blake, Microsoft MVP (Windows Desktop Experience) since 2003

>> > Please Reply to the Newsgroup

>>

>

> --

> Ken Blake, Microsoft MVP (Windows Desktop Experience) since 2003

> Please Reply to the Newsgroup

 

[Ken Blake, MVP]

On Mon, 31 May 2010 19:46:07 -0700, "Kernel"

wrote:



> I'd also like to thank all of the MVPs, and the other guru's, who have

> helped soooo many people over the years. I've used the Google Advanced

> Search with this NG a zillion times, and always found the answer. In fact I

> found a lot of answers and developed a long list of tips that I've saved.

> Mr. Ken Blake, and God Rest His Soul Alex Nichol are only two of the

> standouts;





You're welcome, and thank you very much for such kind words. I'm not

sure I deserve it, but it's a great honor to be ranked with Alex

Nichol, who was one of my newsgroup heroes.







--

Ken Blake, Microsoft MVP (Windows Desktop Experience) since 2003

Please Reply to the Newsgroup