BleepingComputer.com: Mixing 1Gb and 512Mb Memory Stubs

Hi all.

I have an Acer Aspire T660 desktop unit, which came with an internal graphics chipset and 512Mb RAM as standard. Good enough for browsing the internet and doing basic administration - pretty rubbish for playing games. So, I decided the time had come to upgrade.

Went out and bought a 1GB graphics card, and an extra 1GB stick of RAM. I disabled the integrated graphics and installed the graphics card, no problems. (Only mentioning this in case it's somehow related). But when I fired the computer up after inserting the extra memory stub, I found that it was only recognising 1GB of RAM, not the 1.5GB that it currently has in it.

Both RAM stubs are working - inserting them both individually, it recognises both the 512MB and the 1GB, no problems. But when I put them both in together - no matter which slot I use for which stub (I have 2 slots on my motherboard), the BIOS screen tells me I only have 1GB of RAM installed, as does the System Information screen in Windows.

I've heard of occasional problems when people have mixed RAM types; but these seem only to be with "Dual Channel" RAM slots, which usually come in 2 pairs of 2. I've researched my make & model of PC as best I can using Google, and all the sites I've seen to far tell me that I should be able to mix these two differently-sized RAM stubs with no problems, and that my motherboard has a total potential capacity of 2GB RAM.

Does anybody have any ideas, then, why this isn't working? Or what I can do to test or diagnose the problem? I don't know too much about internal hardware, past the basics, so I'm not entirely sure where to begin with looking this up.

One thing's just occurred to me - again, don't know enough about this sorta stuff to know if this theory has any merit - if, as many of the websites I've looked at advise, my motherboard does have a 2GB capacity, could it be that the 1GB graphics card is taking up half of this capacity? And that the board won't, therefore, recognise more than an extra 1GB of RAM?

Any help will be greatly appreciated. Thanks in advance.

Best wishes,

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Khrys.

You are sure that the system recognizes the new module...as a 1GB stick?

Louis

one kind of memery module is it? brand type? is it one of the cheapies off of ebay? often times those are high density ram, and your computer will only recognize half of it. Otherwise, have you tried removing the 512 mb stick and just use the 1 gig and see what happens.

In the original post he said the 1gig stick was recognized.

Sometimes different memory sticks don't play nice with each other. I run into it more often than one would think. Get another 1gig stick and call it a day.

Hi guys, thanks for the responses!

Louis - yeah, I'm as sure as I can be. As I said, when I fire up the system with just the new 1GB stick in it, it does show that I have 1024MB of RAM.

Patriot - Yeah, it WAS a cheapie, as it happens. Not from E-Bay, though; my local PC World re-sells "refurbished" RAM sticks in generic packaging. (No, don't ask me how you "refurbish" a stick of RAM; I don't know either!) As for the actual brand name of the RAM; I'd have to take my box apart again when I get home (I'm in the office right now) and examine the stub, see if I can find a serial number or product ID of some kind. There was nothing on the packaging except the PC World logo and details of the type of RAM. (DDR2, 240-pin, 800Mhz, 1GB). Actually, that's something that's just occurred to me - the other stub, the 512MB one, is only 667Mhz. Could this be affecting things, I wonder? I didn't think it would, as far as I know when you mix RAM of two different speeds the faster one simply goes at the same rate as the slower one; but I could be wrong, here.

Punisher - yeah, that's what I'm thinking of doing; buy another 1GB stick and have done with it, I mean. I'm just a little concerned that I might somehow have reached the maximum RAM capacity of the motherboard; either because, as I hypothesised earlier, the 1GB Graphics Card is somehow taking up half of the board's 2GB capacity - or I'm just wrong about that capacity.

Cheers for your comments. Any further thoughts appreciated.

Best wishes,

--
Khrys.

if you have 2 rams of different speeds, it will default to the lower speed. so if you have ddr2 667 and ddr2 800, the 800 one will only run at 667, but it should still recognize both sticks. punisher, in reply to you he said it only recongized one gig-which if if the one gig stick was high density then it would only recognize 512 mb of the 1 gig stick and 512 mb of the original stick making for one gig total. and no, the aftermarket video card should have its own memory and not use the ram you have on it. the only thing I can think of is you didnt disable the integrated card and its using it, but since you said you disabled the integrated card, then thats not the issue. and since it recognizes the one gig ram module on its own, then its not high density, my best guess is the motherboard requires both modules to be the same size. I would try finding another one gig module and throwing it in there, you can find it off newegg for like 15 bucks.