Errors in Memtest86 with 4 or 8GB memory

[Krzysztof Pierwieniecki]

I have a problem on Intel DQ77KB board. I have two the same boards and 
on every board Memtest86 reports a problem at 2990.8MB. That problem 
occur only if I use 4 or 8GB memory. With 2GB memory everything is OK.

What may be causing errors in Test2 "Address test, own address, 
Parallel"  in Memtest86?
http://www.memtest86.com/technical.htm

Chris

[Scott Duplichan]

Krzysztof Pierwieniecki [mailto:[e-mail]] wrote:

]I have a problem on Intel DQ77KB board. I have two the same boards and 
]on every board Memtest86 reports a problem at 2990.8MB. That problem 
]occur only if I use 4 or 8GB memory. With 2GB memory everything is OK.
]
]What may be causing errors in Test2 "Address test, own address, 
]Parallel"  in Memtest86?
]http://www.memtest86.com/technical.htm
]
]Chris

The USB controller might be using memory reported as
free in the E820 map. The address 2990.8MB would be
around BAECCCCCh. The log file shows that SeaBIOS uses 
memory around there for USB. Yet the SeaBIOS E820 map
shows memory through BAEDCFFF as available RAM. I once
debugged a problem like this. Dumping the failing address
range with a DOS mode debugger showed a location that
was constantly incrementing. That location turned out to
be a periodic counter used by the USB controller. The
problem was E820 reporting the USB memory as free, just
like Wang Fei suggested.
Thanks,
Scott