On Wednesday 28 December 2005 20:22, Bryan J. Smith wrote: > It's not the mainboard. It's the processor. > > The memory controller is on the _CPU_, _not_ the mainboard or > its chipsets. There are literally 368 traces on a > Socket-939/940 mainboard to its DIMMs -- 2 sets of 184-pin > DDR. > > AMD Socket-939 uses Unregistered > AMD Socket-940 uses Registered > > AMD Athlon 64 are configured to use non-ECC > AMD Opteron are configured to use non-ECC or ECC Wrong. Several higher end boards for socket 939 chipsets can enable ECC. The only difference between Athlon64 and Opterons (940, not 939) is the registered part. MSI K8N Diamond Plus (manual page 3-11 for enabling ECC) ASUS A8N32-SLI Deluxe - QVL and spec sheet list both ECC and non ECC. AMD Athlon64 spec sheet lists that both ECC and non-ECC modules are supported. Most low end boards do not have a way to enable ECC. Many don't work if you insert ECC modules. Most higher end socket 939 boards allow you to use ECC Peter.