CBFalconer said:
DaveW wrote: *** and top-posted. Fixed. ***
ECC doesn't depend on the CPU, but the chipset. The CPU never sees
an invalid memory value, since any single bit errors are corrected
before delivery. A multiple bit error will cause an interrupt,
usually halting processing, and avoiding handling garbage data.
To elaborate on that a bit.
The current Intel architecture and the AMD architecture, are a bit
different from one another. The Intel processor relies on the Northbridge
chip for memory services. For an Intel motherboard, you want to check what
chipset is being used, to determine whether the product can support ECC.
For example, the 975X is the most recent Northbridge with ECC support on
the memory interface. All you need is ECC memory to complete the picture.
On the last several AMD sockets, the memory controller has been inside the
processor. The Northbridge chip in this case, doesn't matter and is
irrelevant to ECC support. The S754 socket processors have a single memory
channel. The S939 and AM2 socket processors have two memory channels.
I believe all of them have provisions for ECC. In that case, you still want
to check the motherboard documentation, to see if ECC is mentioned in the
BIOS screens. For example, with AMD, you have choices of SECDED or Chipkill
mode, plus there are scrubber options that may be shown in the BIOS. Background
scrubbing does dummy read cycles while the memory subsystem isn't busy,
looking for and correcting any correctable errors found.
To give an example, on an Asus K8V, socket 754 AMD motherboard, the BIOS
has the following:
Master ECC Enable
DRAM ECC Enable
L2 Cache Background Scrub
Data Cache Background Scrub
DRAM Background Scrub
DRAM Scrub Redirect
ECC Chip Kill (I think this setting may be inappropriate for S754.)
On the P5W DH Deluxe 975X chipset motherboard, they have BIOS settings
DRAM ECC Mode [Enable, Disable, Auto]
If the Intel motherboard used a P965 chipset, there is no ECC support on
those, so no reason to see anything in the BIOS. A P965 motherboard manual
would tell you to use non-ECC memory, and then you'd know it wasn't supported.
So for the Intel processor case, the Northbridge is the determining factor.
For AMD, the support is inside the processor, and checking the processor
documentation is where you'd go to verify the details (like if you want
to understand what Chipkill mode is). The motherboard manual should have
a chapter describing BIOS options, and that is where you check whether
the support you need is present.
Paul
