Newer RAM in an older notebook - will it work?

I will shortly have a spare stick of 1GB RAM from a newer computer, due to a good deal I got on a pair of 1GB sticks for an upgrade. I am wondering whether I can "mix" this with an older stick of 512MB RAM, or even just replace the older RAM entirely, in an older computer.

The specs on the spare stick that I want to transfer are:
1GB
DDR PC2700 •
CL=2.5 • Unbuffered • NON-ECC •
DDR333 • 2.5V • 64Meg x 64 •


The destination computer is a Presario V4135US (2005 vintage). The specs of the RAM currently installed are:
256MB and 512MB
DDR2 PC2-4200 •
CL=4 • Unbuffered • NON-ECC •
DDR2-533 • 1.8V • 128Meg x 64 •

Will the newer RAM work in the older computer? Will it work paired with one of the older sticks? I don't mind if performance of the faster stick goes down to the slower spec, since a total of 1.5GB or even 1GB would still be more than what the computer has now, and I don't have anything else I can do with this otherwise perfectly good stick of RAM.

Many thanks.

 

You cannot use DDR2 and DDR sticks interchangeably. They are different.

 

Not gonna happen.

 

Yes, my suggestion is to just go to crucial.com, run the automatic memory check, and buy 2 1GB sticks and put those in. They will give you the biggest boost. Because each RAM wouldn't match completely. 512 and 1gb don't par up to each other completely, and you can't intermix different ram types such as DDR, DDR2, and different speeds, such as 333mhz and 533mhz. the memory has to match the CPU FSB speed. to find out all of this information if you are up to it, and to be able to run a few simple quick benchmarks, check out:

1. PC Wizard 2008

or

2. Sandra Lite 2009

 

You cannot use ddr2 memory in a ddr laptop. The ddr2 memory module will not even fit because of a pin change between the ddr and ddr2 memory modules.
Unfotunately you cannot put that pc4200 to use, but you can try to sell that pc4200 to compensate for the cost of buying more memory for the older system.

3900th post

K-TRON

 

Different speeds shouldn't be a problem. The problem here is just DDR2 wont work with a DDR-laptop and vice versa.


About the memory speed, let say we have a notebook that has 2x512MB DDR2 533Mhz originally, if you buy 2 new 1GB sticks one that's at 800Mhz and one that's at 533hz that won't be a problem, the stick with the higher spec will just use another SPD to compensate for the slower ram-module and run as a 533Mhz stick.

 

Ah, I see. Did not realize the older RAM was DDR and newer was DDR2.

I knew vaguely what Michel.K explained so well, that it's possible to use a higher-speed stick at a lower speed if you're willing to sacrifice the speed, I just didn't know the types of RAM were different on these two lappies (DDR vs DDR2). Their age is less than 2 years apart! (old one= August 2005, newer one = September 2007).

I'm actually going to stick with the existing RAM since this computer is obviously aging rapidly . We still love it because it's running XP Pro and even with only ~750 MB RAM still seems faster than the new one which is running Vista . Maybe the memory upgrade will get the Vista computer up to par, speedwise.

Thanks everyone for the replies! :wub: K-TRON, glad I could be part of your 3900th post celebration!