MacBook Pro - Mid 2010 - Memory Errors in AHT I have recently inherited a MacBook Pro which occasionally reboots at random. It has 4Gb Ram (2X2). AHT is consistently showing a 4MEM error - e.g. '4MEM/66/40000000:0xa1e45898'

Diagnostics so far:


Re-seating/cleaning modules - same 4MEM errors.       
Swapping modules between sockets - 4MEM error with different 0x value.       
Testing modules individually - no errors (in either socket).


The above seems to rule out the memory modules or the sockets. Errors only occur when both modules are plugged in. Could this be a timing problem between modules? (Original Apple memory).

I have tried resetting PRAM and SMC - same errors occurring.

Any suggestions as to where to go next most welcome.
Seems it was the memory module(s). Installed two new 2Gb modules and ran AHT extended overnight. No errors.