PC2 4200U memory with PC 2 5300 ram

[billmcseservices]

Hello,
I have PC2-4200U 1 gig stick and a 1 gig PC2-5300U stick. Can I use both in the same machine? Sorry just can't remember!

 

[sharkbyte5150]

Yes, it's fine to mix RAM that runs at different speeds (4200 vs. 5300), just know that the slower speed module sets the overall speed your RAM runs at.