Hi, 3 months ago I bought a mac pro from online apple store and I just noticed that in the 'about my mac' window 3 Gb memory was reported whereas I have 4 Gb present. There are 4 x 1Gb DIMM's present. 2 on Riser A and 2 on Riser b, same positions, DIMMS 1 and 2. I pulled them out to see if they were all corectly attached and they were. In the system profile at the tab diagnostic info this is stated: Laatst uitgevoerd: 24-07-08 17:29 Resultaat: Fout (error) Type fout: Geheugen (memory) Geheugensleuf: DIMM 1/DIMM Riser B It's in dutch but it says there is an error in DIMM1/DIMM Riser B. The memory tab window shows this: DIMM Riser B/DIMM 1: Grootte: 512 MB --> same for DIMM Riser B/DIMM 2 Type: DDR2 FB-DIMM Snelheid: 800 MHz Status: OK So the 512 Mb is present in DIMM's 1 and 2 of Riser B whereas they really are 1 Gb each. So I did a hardware test (2x, including the thorough one) but no errors were found. When I then look at the test at start-up it states that there is a memory error in DIMM1 Riser B. Could it be broken or is it just a bad report?