2-4GB Ram in Windows XP home

[akaqueequeg]

Hi everbody,

I know this subject has been banded about alot in the past. I have read much of the stuff on net about this be I'm still confused.

My understanding is that windows XP has 4GB of adresss space. Windows will only recognise approxiately 3G of this maximum because the upper 1 GB is used to allocate adress space for internal devices. Hence the total amount of memory you will every see is 4GB minus the require device adress space depending what you have installed.

I'm also of the understanding that Windows will do this automatically and that since SP2 switching on the 3GB setting or moding the ini to PAE wont do anything to change this.

So my question is this do I buy 2G or 3G of ram? If I XP can recognise just 0.75 more I will get the extra head room.

Rig

Quad Core Q6600 cpu
Abit p35 Pro Mobo
2-3GB Crucial Ballistics 8500?
Creative SB Audigy
Geforce 8800 GTS 512mb
WD raptor 10,000 SATA Raid 0 (2x36GB)
Maxtor 150GB 7,200 SATA
CDDVDR
Floppy
Hiper R 580W PSU

 

[kimsland]

2 Gig
I have never seen anyone use past this amount (2 Gig+ in use) on Xp

 

[resu]

yea i think if you wanna be playing with big boy RAM sizes then its vista 64 or linux as i believe they can handle more.

ive never seen a xp machine with more than 2gig tbh

 

[SNGX1275]

resu - there is XP64 that will handle 4+ fine, and linux still has the 32bit limitation. You need a 64bit OS to go over 4.

To answer the original question. You are probably fine sticking with 2 gigs. If you want 3 gigs and you have 4 RAM slots you could go 2 1gig sticks and 2 512meg sticks, and at least that way you'd keep the dual channel thing going. But if you just do 3 1gig sticks you lose dual channel.

 

[resu]

oh yea lol always forget about xp64

hehe

havent seen a copy for ages

 

[akaqueequeg]

Right I have done some further research on this and think I got a grip on it.

In summary

To use more than 2GB in on your desk top computer you need the following

1) a motherboard that can support the amount you want to run
2) a CPU that can do 64bit processing, a quad core for example
3) Windows XP 32bit, Vista 32bit

To use more than 3.5G you will need the same as above but Windows XP 64bit or Vista 64bit instead

The way it works for those previously confused like me is 32bit OS systems have both 4GB of Physical address space and 4GB of virtual adress space.

Virtual adress space has nothing to do with the amount of phyiscal memory windows can use. This is adress space is divided in 2GB of virtual memory for the OS and 2GB for applications. If people every advise you to add /3GB code to the ini boot file then this will have no effect unless you are running programs that want more than 3GB of virtual memory and it still wont have any effect on physical RAM full stop

Physical adress space is a total of 4GB but for each device that uses RAM/ROM then this must be adressed. After all your other hardwares memory has been adressed than the remaining adress space can be used for system memory.

Therefore with my 512mb GTS is going to be taking up over 512mb most likely, on top of this I will have the Bios, PCI sound card etc meaning Iam unlikey to see anything over 3GB

Anyway hope my finds help any others with the same situation

As for 2 pair 512mb modules the only ones I can find are

HyperX/512MB 1066MHz DDR2 Non-ECC CL5 HyperX 512MB, 1066MHz, DDR2, Non-ECC, CL5 (5-5-5-15), DIMM-240pin, 2.2V, CL5,

These run at the same voltages timings and MHz as the crucials.

Has anybody got experience running Ram from 2 different manufactures? I dont intend to overclock them so i'm not worried about the overclock performance being similar.

 

[gbhall]

Mixed manufacturers are not usually a good idea, but if it gives problems, hey just take 'em out again.

On the other hand, going to a 64-bit OS (XP or Vista) is very sure to give you all manner of compatibility problems at the moment, that's with independant software, as well as considerable trouble with stability of drivers, plus the never-availability of drivers for kit older than 18months or so.

In short, MS have no real incentive to support and properly debug a completely separate OS which has as yet a very minority of interest from users.

I say stick to 32-bit for a while, even stick with a really well-debugged system altogether - it's called XP professional....it will really fly with 3Gb

 

[Didou]

2) a CPU that can do 64bit processing, a quad core for example

It doesn't have much if anything to do with the amount of cores though. Just look for 64-bit support which stems from the Athlon64 (& certain Pentium 4s from the same era) all the way to the Core 2 Extreme parts available now.

 

[akaqueequeg]

"On the other hand, going to a 64-bit OS (XP or Vista) is very sure to give you all manner of compatibility problems at the moment, that's with independant software, as well as considerable trouble with stability of drivers, plus the never-availability of drivers for kit older than 18months or so"

Yes, gonna stick with xp 32 for as long as possible. I'd rather be able to play my games without crashes, the witcher stucked enough in xp as it was let alone Vista 64

"It doesn't have much if anything to do with the amount of cores though. Just look for 64-bit support which stems from the Athlon64 (& certain Pentium 4s from the same era) all the way to the Core 2 Extreme parts available now."

Yes I know it was an example hence the word example.

Anyway I was bored at work today so got looking at the benchtest scores for 2GB vs 4GB. I found 3 reasonable benchmark sets, all running Vista 64 comparing a series of 2GB sets vs 4GB sets on the same rig.

The biggest performance difference was 19% however the rest of the scores averaged around 10% on the same test group.

The other three only recorded a performace increase no greater than 3%.

I think Iam gonna stick with just 2G, as i'm not gonna see a performace increase at all, because i) i'll be running 3GB ii) there will be mixed modules which will likely no be as faster than a single set iii) those bench scores where on vista 64 which benifits more from the head space because of the OS foot frint being much bigger.

Lastly I looked around to see what peak use XP user where getting on them system memory when running crysis. All agree that there system hit no greater than 1.5GB.

I think I'll wait untill Vista 64 is ready and games are programe with 4GB in mind then then switch to 2x2GB.

 

[gbhall]

Sound, very sound.

Remember XP pro....first release was Oct 25 2001. Barely worked at all until SP1 released 9 Sep 2002. SP2 came along 25 Aug 2004, and improved things a lot, but there have still been by my count

9 updates for IE7
111 updates to XP after SP2 and I'm only counting from April 2005

It's only become the most reliable OS ever from MS over the last 6 months...after 7 years.