While installing replacement modules into an older ThinkPad x40 laptop, I ran into some trouble. I found already installed a single module of 512m PC2700, wanted to upgrade, so I purchased a larger single mod of 1g PC2700. Long story short, the x40 didn't like the 1g mod and did nothing at startup. No display, no warning sounds, no errors...but it worked perfectly with the original 512 mod.
The only difference I could find was with the notations on the original mod, stating that it was DDR 333 PC2700U. Is the "U" of any consequence? What is the difference between the "U" mod and the conventional mod (if any)?
I'd really like to get this thing running with more gas. It's a great little machine. Kinda like a pre-netbook netbook, perfect for my 7-year-old daughter to cut her teeth on.
I really appreciate any help you guys can provide.
More aboutdifference pc2700 pc2700u
I found some pretty helpful information in this thread. I'll try and see whether or not the ECC state of the modules is a factor, though I'm sure treefrog07 is correct.
Also failed to mention that the ThinkPad x40 has built in 256m (likely unbuffered) of memz, so that is apparently what has caused the conflict. Sorry for being vague, this is all new to me.