Intel D975XBX memory test failures

Deep into the process of bringing a new system online I've encountered a BSOD and a couple other odd behaviors that made me wonder if I have a bad memory stick.

The mobo is an Intel D975XBX with two 1-GB 667mhz sticks. E6300. No OC yet.

The first test I used was DocMemory. It generated the following errors.

MATS+:
"Addr: (2046M), Exp.: 55AA55AA, Act.: 55AA00AA"

March B:
"Addr: (2046M), Exp.: 33CC33CC, Act.: 33CC00CC"

...as did all the rest of its tests.

So I replaced the OCZ memory with some Patriot sticks.

Same errors.

I then tested both sets of memory using MemTest86+ v1.65. After one long test it found no errors. But I wondered if it was testing all of memory so I configured it to test BIOS-ALL (instead of BIOS-STD). Then it generated errors:

failing address: 0007fedfe48 2046.9MB
good: 8ce395a0
bad: 8ce300a0
etc. (a long list of errors at the above address)

TuffTest PC's memory test generates failures, too. I can't interpret the errors but there's one per test as with DocMemory.

Then I tried several other memory tests: Microsoft WinDiag, GoldMemory, MemTest3.4, SiSoft Sandra, RightMark, and Intel's own Desktop Control Center. Both sets of sticks pass all their tests.

Intel Reseller Support says to trust only their Desktop Control Center, which they swear tests all of memory (I wonder how, since it runs within Windows). They say not to trust any other tests.

I'd greatly appreciate opinions and advice about whether you think this board is defective. Or are the failing tests the result of the test program being incompatible with this motherboard and/or BIOS?

Thanks.