I built a new computer recently and it works fine, but I've run into a couple of interesting situations. They haven't gotten in my way as yet, it's just a bit curious.

 

Mostly, it has to do with my RAM. I have 3 gigs in here (my motherboard supports up to 4 1-gig sticks, I've only got the three), but the computer only recognizes 2.50 GBs of it. Some other software I have that gives system info (in particular, my battery backup's software that'll shutdown the computer before the power outage nabs it) recognizes only 2 gigs.

 

I'm thinking it's partially because of the way the motherboard is set up: the user manual tells where to install the RAM, but it doesn't offer any set-up for 3 sticks, only 1, 2, and 4. I don't know whether or not the computer is using the full capability so I don't know whether or not to complain. Granted, even 2.5 or 2 gigs is more than any game I have will need, but, y'know, bragging rights and all among my friends.

Iirc, you cannot arbitrarily put memory sticks in the slots but have some restrictions. I think that for example the sticks have to be pair-wise identical. What I´m slightly wondering is that 2.5 GB are recognized. Getting 2 GB would make sense since you said yourself that 3 sticks are not supported. I´d assume that you´ll have 2 GB and that the 2.5 GB is buggy. I´d also think about taking out the 3rd memory stick if your mainboard manual states that it´s not supported (or alternatively get a 4th stick).

 

But the last time i put a computer together has been ~5 years ago, so I´m not really up to date on modern technology.

You might have recieved a 0.5G DIMM by mistake. Try to remove them one by one and see what you get. It is likely that you'd get 1.5 then 1 in which case the second is a 512M (you get the idea).

 

Unless I'm very much off, they still make memory clusters as internal-even chips (that is the reason you can have only one as opposed to twin for older models). One of the memory banks might have fried and the computer elliminates it or simple can't see it.

 

Removing them one by one and re-mounting as needed will get you to 2 possible outcomes:

 

* it is related to a chip. Every time you put that in, you get 512 only. In which case, go see the store that sold them to you. It's either a 512 by mistake or it's faulty. Both cases, you get a 1-gig

 

* It is not chip related. In which case you might have to deal with some limitations. E.g. Motherboard (read the manual), OS (you never mentioned the OS but some have a limit. None have a 2.5G limit though), etc. Is this the POSt report or the OS version? (POST report is the text-only screen you get at computer physical reset. Press PAUSE if it scrolls to fast. Alternately you can enter SETUP, most computers have a report there)

 

If nothing helps, post more info.

 

Oh and IIRC there are limitations on how to use slots but it's not parity related, but order-of-load. E.g. four slots need be loaded in a 1-3-2-4 order on my MB. Twin chips sell as such and i doubt the store would sell you a single chip. They both come in the same case.

Check the manuals that came with the RAM itself. Oftentimes you have to pair them up with equal-size and -speed chips, as Atheist said.

 

Also, check out your graphics card - some of the integrated ones will allocate themselves part of the main RAM.

Alright, update on this front: I got a new gigstick today, and now I'm in an interesting boat. I finally paid some attention to my bios, and it's clearly recognizing 4 gigs. Meanwhile, My Computer->Properties reads 2.00 GBs still, as do other programs. So I've basically gotten myself lost on this lol.

Windows XP will only recognize 2 gigs of ram

Yup, I upgraded to XP x64 and it recognizes all of it. Granted, half of my devices don't work on x64 due to lack of drivers, but at least I've solved that problem.

Lol... not a good tradeoff

 

stick with 2gb since thats more then you'll need (at least for 10 months or so heh)

 

EDIT: you could also try windows vista. I'm sure any ram restrictions are raised higher then XP.

Use the /3GB switch to enable address of memory up to 3GB in XP Professional.

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