Ok, thanks for that clarification
Memtest showed no fault in testing all 4 modules on the 2 channels, which is the reason I queried it. From what you are saying, if no fault turned up as a group, Memtest would be unlikely to show a fault with a single chip, or am I misinterpreting?
Unfortunately I didn't get matched pairs, only 4 off of the same Make and Type, all manufactured in the same batching week, Y10,Wk43. I am not sure if it is of any significance, but the serial numbers are 3E2E9B63, 3E2E9CDA, 3E2E8DAC and 3C2EA304.
Anyhow, finished the tests this morning, and I could not positively replicate the problem. I tried every possible combination from single through to quadruple chip in every slot combination with no problem on cold boot at all.
However, all the more puzzling is that occasionally, and I mean occasionally, restart from Win7/64 such as following a sytem update this morning, would cause no short beep, 3 beeps, repeat, then short beep then boot normally. I tested restarts for 5 occasions since with no issues, and cold boot 4 times with equally no issues.
It may not be normal and puzzling into the bargain, but if the system ultimately works I can live with the occasional annoyance. Curiosity caused my question to arise, but there appears to be no clear cause, so I guess it remains an unexplained anomaly....
Anyhow, the Noctua is still not here, but I gather the temperatures I reported are normal for the chip, so that is no longer a worry.
ET6 I will possibly try thereafter, but it would not appear to be well regarded as a tool, so I will not expect too much from it.
Once the new boot drives are installed and the OS is up, I'll consign Express Recovery 2 to the trash, as it has caused me more problems than it is worth. Mirroring or ghosting the OS drive would appear to be the better solution anyway.
Many thanks again guys for your help and patience.
Best regards from wintry Romania