Can I mix different RAM types? (from old PC into new)

[Rudyard]

Ive just taken another part (dvd drive) from my 2003ish P4 machine that died earlier in the year. At home I have a 2 y/o (3 at most) Pentium D machine with 2 gb ram in 2 1gb sticks. I noticed in the older machine the ram and wondered if it would do any harm to my PC to add the 2 512 mb sticks to take my total RAM up to 3gb?

Its 32bit XP and I know its probably overkill but I have maxed my RAM to the point of none left when using large photoshop files doing some design work so possibly once in a blue moon it might be useful.

But as its older RAM and a different brand and in different sizes a - is it possbile to do and b - would it harm or affect my PC peformance in a negative way at all??

Better than throwing it in the bin!

[redwudz]

First make sure it is the correct type of RAM. DDR, DDR2 and older versions all have different RAM sockets and pin counts. Those aren't interchangeable. If it is the correct type, it may work, but it will default to the lowest speed stick in the bunch.

Some motherboards may also have a problem with mixing RAM and it may not boot correctly or you may have errors. You could run Memtest 86 to check for errors if it does boot: http://www.memtest86.com/ I would check your motherboard specs to see what RAM the manufacturer suggests.

You can also use CPU-Z to tell you more about your present RAM: http://www.cpuid.com/cpuz.php

One last point you may be aware of, a 32bit operating system can only address about 3.7GB of RAM. If you add more it won't do anything. A 64bit OS can use quite a bit more.

RAM isn't that expensive at present. I would just use RAM that you know will work and you may have less problems and better performance.

[craigarta]

Yes check the ram. I got a stick of PC-4200 ram last year stuck in my machine and fried my MB and the ram.

I found out I was supposed to get I think 3200 or 3800.

But the manufactorer replaced it and the kids pc had 4200 and I put in there and it has been going strong ever since.

[filmboss80]

If you can find out the motherboard brand and model number, you can do a web search for the installation manual. See what the manufacturer says about mixing and matching RAM. But if you are unable to find the info:

When in doubt, take the safe route; match your RAM exactly.

[aedipuss]

mixing old ram in with newer is not a good idea, even if it is the correct type, it most likely runs at a slower speed. since motherboards only have one setting for all ram, it will force all the ram to run at the slower speed.

[Rudyard]

Cool, sounds like more potential trouble than gain, I thought if it was simple as mixing 2 different hdd's for example id do it but if it may lead to problems ill just give it a miss.

Im not in need of the extra stuff, just thought it was better than throwing it out, but no need to create a problem that isnt there!

Thanks all for your advice.