Question: about RAM

Thought I would run this by some of you techies.

I have 2x1GB DDR2 installed into 2 of my 4 RAM slots (dual channel).

I have 2 free slots, both yellow, the other two are purple (being used), denoting which slots to use for dual channel I guess.

I want to add more RAM, since installing vista I have noticed my HD working a little harder.
I have Vista 32bit I know the limit is 3.5GiG, so...

1. Should I buy 2x512 DDR or 2x1GB DDR?

2. Will vista just ignore 1 of the 1GB moduals if I go with 2x1GB or use half of it?.

3. Will Dual channel work if I install 2x512 along side my 2x1GB (same make & speed moduals)

going to bed now, hope you can help =D

http://www.codinghorror.com/blog/archives/000811.html
http://www.vistaclues.com/reader-question-maximum-memory-in-32-bit-windows-vista/

The google knows all, bow before the google.

Yep, post here. Software writers are renowned for their knowlage of Hardware. Mind you some one will probably know

Technically, it will use all of it, you just won't be able to access some of it. How much you can't address will depend on other factors. You see the problem is that 32bit Windows has 4GB of address space, and this has to include video memory and other things. If you have a 512MB videocard, you're down to 3.5GB on that alone. I understand it can even go down as low as 2GB, although this is rare and presumably happens only if you have some pretty heavy duty peripherals eating up address space.


Normally, yes. Ram sticks have to be matching pairs, but only per-channel. You might check your MOBO manual to be 100% because there's always one that does it differently. And you might also check the guidelines for color matching, as ( just to be difficult! ) some motherboards expect you to use different colors for each pair ( ie: one purple and one yellow for each pair ) whereas most expect you to do the logical thing and have one pair in the two purple slots and one pair in the two yellow slots.

Hey, programmers are like racing drivers: they know how to drive the thing, they just dont know much about fixing it. :P

2. Vista will use however much isn't used by the PCI bus mappings on your computers. Your motherboard and PCI devices get assigned a memory address to communicate with, and addressranges used by hardweare won't be available to map to the RAM, hence the decreased amount of memory you'll see.

Depending on what hardware you have, if you put in 4GB you may see anywhere from 3GB to 3.75GB. the most common one I've run into myself is 3.25GB on dell workstations when 4GB is present.

Now, I have *no* idea if you'll be able to get the dual mode stuff working properly if the memory won't be accessible in its entirety... Maybe it's OK, might give problems -- haven't tried that myself. :-?

Ill go with 2x1gig then, I do have a 640MB gfx card but I should get a little more from 2x1gig than 2x512.

*could*, not necesarily should.

I've seen machines end up with 3.25GB that had a 256MB video card.

More than 2 gigs of ram will not do much of anything if anyhting to increase the speed of your system in games or apps, but causing dual channel to be disabled because you have more than two sticks installed or four sticks of different types/size ram will probably halve the speed of your ram.

So I suggest you just yank out the 512 sticks and stick in a couple 1 gig sticks.

With an AMD CPU you'll have problems to get this ram combo working.