Regarding yesterday’s entry about ECC memory errors under heat stress—a diglloydTools run-stress-test test run this morning of 90 minutes showed no ECC errors. However, the ambient air temperature (as reported by the Mac Pro itself) was 73° F, and the memory modules reported temperatures about 10° F cooler than yesterday’s test run. This suggests that adequate cooling is indeed an important factor with Mac Pro memory, and leads me to the following recommendation—
How to run a memory stress test
To test that your Mac Pro memory is robust under duress, place the Mac Pro in a location in which the ambient air temperature can be allowed to rise at least to 85° F, but not more than 95° F.
Use diglloydTools run-stress-test to yield a maximal load on the machine, using enough copies (one per Terminal window) to test all but about 1GB of memory. Use of 'nice' is suggested so that you can perform basic tasks like reading mail while testing, but don’t expect to get any Photoshop work done while running this test.
For my 10GB Mac Pro configuration, I use four (4) copies of 'dlt' as follows:
nice dlt run-stress-test -l verbose --memory-per-thread 560M --duration 8h
(See the diglloydTools documentation for details). Four copies of the above will test about 9GB of memory (4 X 4 X 560MB). You can adjust the amount of memory, so long as it does not exceed the available physical memory. The output will look something like this:
While the test runs (and afterwards), be sure to check for ECC memory errors periodically (see yesterday’s entry).