Hello Robert,

Monday, May 13, 2002, 4:42:03 AM, you wrote:

RC> I tried unsuccessfully to upgrade the memory in my SuperMicro P6DBE
RC> motherboard from 128 MB unbuffered ECC CL3 to 512 MB (2x256) registered
RC> ECC CL3.  (Both memories are PC133 even though the motherboard is
RC> limited to 100.)

RC> The system has been running fine for over a year with the 128MB
RC> unbuffered, but fails to pass the POST tests with the 512MB registered
RC> -- the AMI BIOS issues a 6 beep code, indicating a gate A20 failure.

RC> My user's manual specifies "512 MB unbuffered 3.3V SDRAM or 1 GB
RC> registered SDRAM". Can anyone tell me if this means that registered
RC> memory will work only with the full complement of 1GB? If so, I'll spend
RC> another $200 for 2x256, but I would hate to do that if it still won't
RC> work. My other option, of course, is to go back to unbuffered, but I
RC> would like to use the registered if I can, since I just bought it for
RC> this purpose.

RC> Thanks,
RC> Bob Castorf

I think that the problem is in the old mobo.
For example my old MS-6163 mobo has the following specs:
"The mobo supports a max memory size of 384MB(8Mx8) or 768MB(16Mx4)
registered DIMM for SDRAM...
WARNING! There are two kinds of DIMM specification supported by this
mobo: PC100 and PC66. If you use 66MHz CPU Bus Frequency, these two
DIMM Specs. is supported. If you use 100MHz CPU Bus Frequency, only
PC100 DIMM Specs. is supported."
 My newer mobo KV200 has he following specs:
 "...These DIMM sockets only support 3.3V unbuffered SDRAM modules.
 WARNING! The chipset does not support ECC. However, the ECC memory
 modules may still be used, but the ECC function will not be
 available."
 Another newer mobo K7VZA:
 "For this mobo, you must use 168-pin non-buffered DIMMs. The memory
 chips must be standard or registered SDRAM...

 The only problem that I had was with my old Socket 7 mobo, which
 didn't read the new PC133 64MB RAM (it saw only 16MB!).

 In any case try to check your new RAM on another mashine (one by
 one).
 Before bying additional RAM (last december I bought 256MB Trancend for
 33$!) borrow it from anyone to check!

--
Best regards,
 Yakymakha

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