Have someone had problems with ECC 667Mhz apple memory on mac pro? I had bought mine with four modules of 512MB and after an year and a half two modules were no more recognized. Looking inside my mac I saw a red light on my DIMM Riser A clearly indicating that a memory bank was broken, I suppose that just one of them is broken because I know that this memory works only in dual-channel. After this problem I bought four banks of IBM Chipkill memory for a total of 8GB of ram and I place them in DIMM riser A DIMM 1-2 and DIMM riser B DIMM 1-2 with my my old two 512MB working Apple memory banks in DIMM riser A DIMM 3-4. Is this a good configuration? I ask this because after the last 10.5.3 update at reboot my system profiler showed two 1GB modules in DIMM riser A DIMM 1-2 instead of two 2 GB modules. After a shout-down this issue disappeared. Any suggestion or similar problems out there?