RAM QUestion

[TURIN]

I recently had my Media Centre PC fail.
No POST and constant beeps.
After some internet research and a bit of trouble shooting it turns out one of my 1gb RAM sticks is goosed. It had a total of 2gb.

Good so far.
After a bit more research I decided to upgrade my RAM while I'm at it.

I was going to go for a matched pair of 2gb RAM to acheive 4gb total RAM.

MY OS is Vista 32bit. (Yes,yes, I know)
My understanding is that it will only recognise up to 3.5gb but probably only 3gb of RAM.

The question therefore is, do I go for the matched pair and upgrade to 4gb RAM or just stick a 2gb RAM in with my current (and only working) 1gb RAM giving 3gb total RAM?

Which will give the better performance, bearing in mind the age of my machine, approx 8yrs and the factit is my primary source of TV/media.

Thanks as always, in advance.

[mixture]

My understanding is that it will only recognise up to 3.5gb but probably only 3gb of RAM.

in Microsoft's words....

To avoid potential driver compatibility issues, the 32-bit versions of Windows Vista limit the total available memory to 3.12 GB

Just go 2+1. On a cheap 8 year old PC you're not going to notice a huge difference anyway.

Oh, and please do us a favour and don't fiddle with the PAE switch if you've been reading things on the interwebs.

[TURIN]

Thanks mixture, I thought as much.

I don't even know what a "PAE switch" is.

I must google that.....

On a cheap 8 year old PC you're not going to notice a huge difference anyway.

Oy! Who said it was cheap? This thing cost me an arm and a leg back then. As did the new motherboard when it got cooked a couple of years back.


Cheers.

[Milo Minderbinder]

it isn't as black and white as that.....some machines will recognise the full 4GB, some won't. Depends on the motherboard BIOS and the northbridge involved (but please don't ask me to give examples.....)
Last year we installed a bunch of Dell Optiplexes which DID appear to see all 4GB. At least they reported all 4GB. Whether they actually used it is another question....
But the reality is (as has already been said) on a machine of that age and performance, there is likely to be little visible difference in performance between 3GB and 4GB

[Albert Square]

My understanding was that a 32 bit machine could address up to 4 Gig of Ram. But that also includes the RAM on your video card. So a 1 Gig card leaves only 3 Gig Ram that can be addressed. Smaller card, more Ram.

[MacBoero]

Doesn't the choice between 2+1 or matched 2+2 really depend on whether or not the motherboard has dual channel memory architecture?

[MG23]

Originally Posted by MacBoero

Doesn't the choice between 2+1 or matched 2+2 really depend on whether or not the motherboard has dual channel memory architecture?

Newer Intel CPUs don't care that much; with 2+1GB in the same memory channel the first 2GB will be dual-channel and the last 1GB will be single-channel.

Older ones may have problems. No idea about AMD.

[le Pingouin]

Dual channel is hardly likely to make a discernible difference.

Milo, my understanding is the 4GB reported is simply saying the system has 2x2GBmodules. PAE is the only way to actually use the full 4GB.

[MacBoero]

Originally Posted by MG23

Newer Intel CPUs don't care that much; with 2+1GB in the same memory channel the first 2GB will be dual-channel and the last 1GB will be single-channel.

Older ones may have problems. No idea about AMD.

The channeling is within the motherboard chipset, and it only works when the adjacent memory modules in each channel match properly, hence the market for matched pairs of memory modules. Thus a 2+1 setup could harm the performance of the machine, as opposed to a 2+2 setup, even if only 3GB of it is used. It may of course be the case, that dual-channel operation has little or no impact in the OPs usage. My guess for media centre operation it doesn't matter, but not for the reasons you give.

[MG23]

Originally Posted by MacBoero

The channeling is within the motherboard chipset, and it only works when the adjacent memory modules in each channel match properly, hence the market for matched pairs of memory modules.

Not any more.

Modern Intel CPUs don't care whether the memory size is the same (I believe timings do still have to be the same). They'll use dual-channel access for as much of the RAM as they can, then drop back to single-channel for the rest.

Which does hit performance, but less so than running the two DIMMS in single-channel mode.

[Milo Minderbinder]

"My understanding was that a 32 bit machine could address up to 4 Gig of Ram."

its not the machine thats the problem: WINDOWS has an artificial restriction built in. My understanding is that if you use 32-bit Windows Ultimate, the restriction goes away. It was partly a marketing restriction by M$ to differentiate between the various Windows SKUs.
But as I said earlier - its a funny situation with some machines reporting the full value.
As to single / dual channel: for most uses you won't see any difference in performance. You have to be really hammering the machine for it to show

[MacBoero]

I can't find anything to support your statement MG23. All the information I have seen, and the experience and documentation that was supplied with the dozens of machines I work with at the moment, tell me:

Multi-channel memory architecture is a feature of the MOTHERBOARD.
Dual, triple and quad channel motherboards will only work in those multi-channel modes, when the memory is in sets of 2, 3 or 4 respectively, and if the modules in each set match in capacity and performance characteristics. The moment you introduce a non-matching module into the memory set, the whole lot is reduced to running in single channel mode to all modules.

[MG23]

Originally Posted by MacBoero

I can't find anything to support your statement MG23. All the information I have seen, and the experience and documentation that was supplied with the dozens of machines I work with at the moment, tell me:

Multi-channel memory architecture is a feature of the MOTHERBOARD.

Not in recent years, since the memory controller was moved into the CPU again. I looked this up when I bought my laptop a few years ago, as it came with a 4GB DIMM and a 2GB DIMM, which didn't seem to make sense.

See, for example, 'Desktop 3rd Generation Intel Core Processor Family Volume 1', section 2.1.3.2, 'Intel Flex Memory Technology Mode'.

[mixture]

My understanding is that if you use 32-bit Windows Ultimate, the restriction goes away. It was partly a marketing restriction by M$ to differentiate between the various Windows SKUs.

Oh for gods sake man !

I wondered how long it would be before someone came along playing the Microsoft money grabber card.

Go here scroll down to the section entitled "Physical Memory Limits: Windows Vista" and then come back.

[Milo Minderbinder]

suggest you read this
3 GB barrier - Wikipedia, the free encyclopedia

and this
HOW TO: Removing 4GB Memory Limit on 32 bit Windows

you'll see that addressing the whole memory is totally possible, and happens in some server versions of Windows
and from separate references I've read, SOME iterations of Win7 Ultimate

Its an artificial limit

[mixture]

Its an artificial limit

Erm...no its not.

Apple, Windows or Linux.... 32-bit is 32-bit ... you're never going to be able to address more than 4GB no matter how hard you try.

Anyway, I don't know why we're having this pointless discussion (a) Vista was a waste of space of an operating system, and (b) 64-bit is the way forward anyway.

[MacBoero]

Thanks for that MG23, I have learnt something new. Shocked at how long it has been around though.

[Mark in CA]

Doesn't the choice between 2+1 or matched 2+2 really depend on whether or not the motherboard has dual channel memory architecture?

Exactly. Dual-channel memory requires matched modules. Not a matter of the OS.

[le Pingouin]

Ermm, yes you can Mix. You mentioned PAE yourself & I've used it with Linux - 8GB RAM on 32-bit. For many distros if you have the RAM and choose 32-bit a PAE enabled kernel is automatically used.

I wouldn't call it an artificial limit as such but you can't argue that MS deliberately chose not to use PAE.

[mixture]

Ermm, yes you can Mix. You mentioned PAE yourself & I've used it with Linux - 8GB RAM on 32-bit. For many distros if you have the RAM and choose 32-bit a PAE enabled kernel is automatically used.

PAE = 36-bit..... and its not some secret switch, its something that's very much not to be used unless you know what you're doing !

You won't get more than 4GB per process on 32-bit no matter the operating system.