Windows XP Memory Question

[markl 1]

I am currently trying to fine tune my system and I am wondering if I have too much memory installed for XP 32 bit.

(Yes I am staying with XP 32 bit for awhile yet)

 

Currently I am running XP SP3 with 4 gig ram, plus my video card with 1 gig ram.

 

This gives me a total of 5 gig of memory. With XP does the 1 gig of video memory have to be mapped into the 4 gig limit of XP by windows or is it separate?

 

I just want to ensure my system is able to use all the video memory without conflicting with the 4 gig system ram.

 

If necessary I can replace the 2 x 2 gig sticks with 1 gig sticks.

 

Any advice on XP memory would be appreciated.

 

Regards MarkL

[mikeymead 17]

Hi Markl,

 

As far as I'm aware the 4 gig limit does include the video card ram as well so you are exceeding XP's 32bit memory limit.

 

Now as for having to replace the 2 gig sticks with 1 gig sticks I not so sure about as at this point I run out of knowledge.

 

My current system has 3 x 2 gig sticks (Triple channel Memory) and 1 gig video memory, I run this system in both XP 32bit and Win7 64 bit with no real issues.

 

Hope this helps a bit

 

Mikeymead.

[Von Paulus 8]

It's independent. One thing is your graphic card inner RAM the other is your system RAM. So you don't have 5GB. You have 1GB Graphic card and 4GB of system memory.

From those 4GB, XP (32 bits) will only address around 3GB.

If you have a graphic card with no inner memory than, the graphic chip will use your system memory. Those are usually onboard cards.

[itifonhom 6]

As far as I can remember from the time I was trying to optimize FSX, Win XP SP3 can use only 3GB RAM and it's independent from the graphic card memory. So you got 1GB more as Win can use. Also, it's better when you got your RAM in pairs and placed on the motherboard accordingly (paired), refer to your motherboard guide. This way the RAM works much quicker. At most MBs, if not every, the slots are colored in pairs, usually the first slot is paired with the third, second to fourth etc.

[Tamper 9]

It is not true that XP can only use 3G of RAm. 32-bit systems can access up to 4G of memory not 3G as stated above (although there is some mathematical rounding taking place, because a 'gig' is not exactly one billion, nor is a 'meg' exactly one million). The 4G 'limit' does not include the memory on a dedicated gaphics card - but it is *affected* by the graphics memory.

 

The thing is, if you have 4G, a good deal of that last gig is tied up by some fairly stupid memory management on Windows' part, so you'll never see a machine with 4G physical memory actually report 4G in the system properties. It will always be less, and usually it's around 3.2-3.5 G. What determines the exact number, among other things, is the amount of memory your video card has on it. Oddly, it seems this only happens when you have more memory than 3G in your system.

 

Von Paulus is correct, you do not have 5G memory total, it is actually 4G - and they are separate...but the way it's handled on a Windows machine, they might as well be combined, because of this silliness with video memory determining how much of the 4G physical memory Windows has access to. VP is also correct in saying that if you have an 'on-board' graphics adapter, the memory for that is usually taken from the system's physical memory.

 

You have to understand that all this wasn't considered a problem long ago when it was conceived; the idea was no one would run into a 'barrier' at just over 3G because - at the time - no one was even close to that much memory.

 

As to your question, I do not think you'd benefit, but if you're worried that the 1G on your video card is affecting your 4G physical RAM, there is some loss due to the size of your video card memory. I still think you're better off than having only 3G - because, even if the number isn't quite 4G (with 4G installed and the 1G video card), it's still more than just 3G.

 

HTH

Edited October 31, 2011 by Tamper

[markl 1]

Thanks for the replies.

 

It looks like I am safe with what I have, so I will leave it as is.

 

The whole memory thing seems quiet complicated for us beginners.

 

Regards MarkL

[Tamper 9]

Hi markl,

 

It can be rather confusing...here's a link that discusses this, maybe it will help:

 

http://en.wikipedia....ki/3_GB_barrier

 

Note the first line: "In computing, the 3 GB barrier is a limitation of some 32-bit operating systems running on x86 microprocessors. It prevents the operating systems from using more than about 3 GB (3 × 10243 bytes) of main memory (RAM). The exact barrier varies by motherboard and I/O device configuration, particularly the size of video RAM; it may be in the 2.9–3.5 GB range."

 

Although this article refers to it as a "3G barrier", it shows how the memory is affected by video memory and I/O devices, and can actually show memory out to about 3.5G. It also discusses how Microsoft was complicit in the situation, choosing to disable the hardware's access to this 'top-end' memory in 32-bit OS's, as a work-around for compatibilty.

[Von Paulus 8]

There was a stranger case in this forum a couple of years ago. Our missing pilot Duce Lewis, bought 2x2GB and windows only recognized 2.5GB.

Probably this was due to a combination of Motherboard and graphic card. It was a Dell. We tried everything but the result was always the same.

He was going to replace the motherboard, but never reported back, he's been missing since then. :(

It was with this case that I learn about the issue that Tamper is referring to, that it could depend on graphic cards and other components as well.

That's why I'm using always the word "around" 3GB.

Edited October 31, 2011 by Von Paulus

[Tamper 9]

There was a stranger case in this forum a couple of years ago. Our missing pilot Duce Lewis, bought 2x2GB and windows only recognized 2.5GB.

Probably this was due to a combination of Motherboard and graphic card. It was a Dell. We tried everything but the result was always the same.

He was going to replace the motherboard, but never reported back, he's been missing since then. :(

It was with this case that I learn about the issue that Tamper is referring to, that it could depend on graphic cards and other components as well.

That's why I'm using always the word "around" 3GB.

 

'Around' 3G is a good way to put it, because I don't know of any specific formula that will yield the exact result you see when you actually plug everything up and run it. Seems to vary a fair amount, based on what I've seen, and not necessarily according to a hard and fast rule or two.

 

I think things like this can lead to the situation you decribed with the "Dell from Hell" :) Although Microsoft certainly did their part in this, it's also true that each machine's BIOS will have an impact on this, because the machine's BIOS is primarily responsible for memory allocation before Windows gets ahold of it. I think there may even be some BIOS settings that have some impact on how memory gets allocated (like using system memory for on-board graphics, video and BIOS "shadowing", the so-called "graphics aperture"...

 

I wonder if your efforts with that Dell unit included a video card with a different amount of memory on it ...?

[Von Paulus 8]

I wonder if your efforts with that Dell unit included a video card with a different amount of memory on it ...?

Oh yes. Only it was a Dell... Duce bought a new graphic card but it didn't work with Dell's original motherboard.

It was one of those situations, that if there was a hammer nearby...

Edited October 31, 2011 by Von Paulus