Memtest Test5 Errors: P4C800 Deluxe and Corsair XMS3200C2PT TwinX Modules

I have been having problems getting Memtest86 to pass Test5 with my 2 - 512MB Corsair XMS 3200C2PT TwinX modules in my Asus P4C800 Deluxe board. I don't think power is a concern since have an Antec TruePower 550. Here is what I have tried so far: -Latest Bios: Upgraded to 1008 first then upgraded to 1011 -Disabled USB Legacy Support -Disabled MAM,PAM (AUTO) -Manually set DDR speed to 400Mhz -Manually set Memory Performance to Standard -Upped the Vdimm voltage to 2.75 -Tested both modules in dual channel mode at SPD values in the blue and black slots. -Tested both modules in dual channel mode at manual timings of 2.5, 3, 3, 7, 8 in both sets of slots. -Tested each module individually in each of the slots at SPD values -Tested each module individually in each of the slots at manual timings of 2.5, 3, 3, 7, 8 Under each of the aforementioned scenarios I always get errors (2-62 on one module and 1400-3000 on the other module) in test5 within 1-5 passes. The only way I can pass test5 is to clock my memory at 266Mhz instead of 400Mhz. I should also note my system doesn't crash constantly but once or twice every two weeks it will randomly reboot and I also get random CRC errors during rar/zip tests. (one test will pass and the next will fail yet the next test will pass... this has to be memory related) Does anyone have any further suggestions or should I just RMA the modules since they constantly get errors when trying to run them at 400Mhz under SPD settings or the reccomended settings of 2.5, 3, 3, 7, 8 at 2.75vdimm? thanks in advance for any suggestions, -Dan PS: Other components in system: -Radeon 9700 Pro -Adaptec 19160 SCSI -WD 200GIG JB -Ultimate HD Cooler for 200GIG (2-20mm evercool fans) -2 - WD 120GIG JB -Pioneer A05 DVD-RW -PlexWriter 12x10x32 SCSI CDRW -Plextor UltraPlex 40xMax SCSI CDROM -3 - 120mm Evercool Case Fans -2 - 80mm PC Power and Cooling Silencer Case Fans

RamGuy, I was just wondering what your impression is of this situation above but adding this to the equation: -Modules both tested OK in another system running at 266Mhz -Modules individually tested OK in P4C800 system running at 266Mhz -Modules each tested bad running at 400mhz in P4C800. So it would seem the modules are definately having problems running at 400Mhz. I just don't know if it is the modules at fault or the motherboard. I have already submitted my RMA request and guess I will start by testing replacement memory. I was just curious if you had run across this particular problem before and if you had any further insight. Thanks so much -Dan

Ramguy, Thanks for the help and for the RMA. I received my replacement modules yesterday and ran MemTest86 for 150 passes on Test 5 using SPD settings and 2.75vdimm and got 0 errors. I am currently in the process of running all the standard tests and so far have made 63 passes with no errors. Looks like it actually was faulty modules. Hard to believe that both had errors. I did have one other question. I tried running the memory at: CAS Latency - 2 RAS TO CAS - 3 RAS Precharge - 3 Precharge Delay - 6 Burst Length - 4 It went through 12 passed with no errors and I will run it through longer tests at a later point in time to make sure it is stable but I was wondering what your reccomended setting for the Burst length is (4 or 8)? Also do you reccomend I keep the vdimm setting at 2.75 or set it back to auto? Thanks -Dan

I'm not the RAM GUY but I'll step in Dan. Leave the Vdimm at 2.75v, it is safe and will definitely help your stability. I have heard a good technical explanation as to why the burst length needs to be 8 instead of 4. I can't recall but I benchmarked with Sisoft Sandra with 4 and 8 on burst length, and all other settings the same. Mine was slightly better with 8. For a more technical version, look around. Or, just test head to head and see what works best for you. Happy Computing, Mike.