I am looking for help in deciphering the following MCE message:

CPU 4: Mchine Check Exception 7 Bank 4: f40f200000000a13 RIP 10: ffffffff8010e5e9 {default_idle +0x20/0x23} TSC d898b471dee ADDR 54999bb20 Kernel Panic - not syncing: uncorrected machine check

Tyan S4882 Quad Opteron M/B
Quad Opteron 875
4X4X2GB RAM 32GB Total (Each bank fully populated)
RH Enterprise 4 2.6.9-22.0.1.ELsmp

I suspect a RAM issue. Also since these are Dual Core processors does CPU 4 relate to logical CPU4 (Physical CPU2)? We have pulled and replaced all memory on the CPU4 bank and the memory address changes on the panic with less than 4 banks populated. It still panics shuffling the memory.

I had the same error on the same motherboard, with 16 GB ram (4x4x1) and with 865's, and had them also with the latest RedHat kernel, and the latest bios (1.05). The errors were still there using only 4 dimms, and even with only 2. Also with different pairs.

I'm running some benchmarks now with a vanilla kernel 2.6.14.2, and it's still going strong. But very likely, when I click on "submit", it will crash... but I'll let you know :-)