X60 RAM issues

[madkat]

It's about the X60 in my sig.
Now it's running with 2x1Gb Hynix modules - both IBM OEM's.

Last week came for some servicing a friend's vaio (absolute junk, but thats not the issue). Coundn't resist the temptation to see how does both the R61 and the X60 in my sig work with 3Gb of RAM (the vaio had a Kingmax module).

The R61 worked like a charm with the module in either slots, but the X60, with the 2Gb in the "right" slot (with the computer upside down, battery up) it refused to boot, giving the classic memory beeps. In the other slot it booted and worked perfecly.

What's the problem? Memory compatibility issue? Known issue in X60? Only one slot working with 2gb modules?