A typical memory isuse with details error messages:

Uhhuh. NMI received. Dazed and confused, but trying to continue
You probably have a hardware problem with your RAM chips
irq 169: nobody cared! (screaming interrupt?)
irq 169: Please try booting with acpi=off and report a bug
[<c0107532>] __report_bad_irq+0x3a/0x77
[<c01077a9>] note_interrupt+0xea/0x115
[<c0107a55>] do_IRQ+0x143/0x1ae
[<c02d68bc>] common_interrupt+0x18/0x20
[<c02d007b>] unix_dgram_recvmsg+0x11/0x1da
handlers:
[<c025b8cc>] (usb_hcd_irq+0x0/0x4b)
[<c025b8cc>] (usb_hcd_irq+0x0/0x4b)
Disabling IRQ #169

Normally we need to replace the RAM chips one by one, unless we know exactly which one is wrong..