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Community Manager

INTEL D975XBX2KR will not boot with all four memory slots filled - gets 3-beep error.


I have a D975XBX2kr that has 4 identical memory modules, Kingston HyperX 4GB 240-pin DDR2 SDRAM DDR2 800 Model KH6400D2K2/4G.

All the memory slots were filled and the computer was running fine. Then one day I heard 3 beeps when booting.


Here is what I discovered:

If I take two of the DIMMs out of the blue slots, the computer will boot. (2 Memory DIMMS in the black slots.


If I leave three DIMMS two in the black, one in the blue, the computer will boot.

If I try to boot with all four DIMMS installed, I get three beeps.

I have cycled all the DIMMS though the black slots - no errors.


Can someone tell me what happened that would cause three beeps to suddenly appear?

Does anyone have any testing ideas?


thank you,

Todd Lastthree



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Valued Contributor III

Your modules are actually DDR2-667 according to JEDEC standards, DDR2-800 achieved by overvoltage in signal lanes from standard 1,8V to 1,85V or even 1,9V. So due the time memory controller inside MB chipset slightly degraded and become uncapable to work with four DIMM filled. Reduce memory speed & voltage to 667/1.8V in BIOS and try with four DIMM again. If work, this is your config till the end of PC life.

Community Manager

I tried the setting change and nothing changed. The computer had previously worked with all four memory slots filled. It just started giving the three beeps memory error after being turned off for a couple of days.

More information: I just noticed that with two DIMMS in the black slots, the computer only sees one. It reports that only one slot is filled. However the computer boots with no error message.

New Contributor I

I ran a D975XBX2 for a few years. I think it only officially supports 8GB total memory. From your original post, it looks like you are trying to install 16GB.

I'd suggest that you download the "Technical product specification" from and compare your configuration against the permitted memory configurations.

From the "Technical product specification" document

1.4 System Memory

The board has four DIMM sockets and supports the following memory features:

• 1.8 V and 1.9 V DDR2 SDRAM DIMMs

• Unbuffered, single-sided or double-sided DIMMs with the following restriction:

Double-sided DIMMS with x16 organization are not supported.

8 GB maximum total system memory. Refer to Section 2.1.1 on page 49 for

information on the total amount of addressable memory.

• Minimum total system memory: 128 MB

• ECC DIMMs and non-ECC DIMMs

• Serial Presence Detect

• DDR2 800, DDR2 667, and DDR2 533 MHz SDRAM DIMMs

Community Manager

Sorry for the confusion, I have four 2GB DIMMS, Kingston KHX6400D2K2/4G

Capacity4GB (2 x 2GB)

Speed DDR2 800 (PC2 6400) (16 128x8 SDRAM)Cas Latency 5Timing 5-5-5-15Voltage 1.85VHeat Spreader YesI also have four Kingston 2GB DIMMSKVR800D2N6K2/4G

That I have also tried with the same results.

They are: 1.8V with 128x8 SDRAMS

I have had both sets installed at different times in the computer working fine and showing 8GB. 

















Community Manager

Here is an update - after looking at the documentation.

If I install memory in Slot 0 of Channel A and B (blue connectors) I have no problems and can get 4GB to show.

If I install memory in any Slot 1 Channel A or B or Both (black connectors) I get three beeps on boot.

I have swapped the memory DIMMS to the blue connectors and verified that all four will boot without issues in the blue connectors. So it is clear that the memory is not the issue.

It would appear that there is a problem with the motherboard.

I'm guessing that there is no repair program for boards this old.

I'm rather dissapointed as of all the computers I have ever owned, this is the first that has had a bad motherboard.