Seems to me this is exactly what we were talking about, just before we started talking about something else.
I have yet to get my b-die to overheat at 1.5 volts with fully tightened timings and I mean tightened. They are 4xDIMMs with hardly a space between them. In the most stressful test they pull 6-7watts. There are kits that are fine upto 1.6 volts. There are RAM kits that overheat quickly if the voltage gets too high. The watts of the RAM is very low and it takes hours most of the time for it to reach maximum temps. You can get tons of dust on the DIMMs and not overheat. Game loads are very low. He states he passed prime 95 and tm5. He needs to troubleshoot and of course clean his case at least once per month.
Getting them to overheat, fail takes extreme timings and voltage for me. Even so I like putting a fan over the RAM sticks. They hit 50c without it, measured with a multi-meter.
There is two main timings that are affected by heat with b-die chips. So long as you don't go too high you are fine. Also most people go too high and report they are fine. This is a video of 1.61 volts into b-die, DDR4-6000.
The tRFC timings are very dependent on temperatures, as they are related to capacitor leakage, which is affected by temperature. Therefore, higher temperatures will need higher tRFC values. tRFC2 and tRFC4 are timings that activate when the operating temperature of DRAM hits 85 °C. Below these temperatures, these timings don't do anything. B-Die is temperature sensitive, and its ideal range is ~30-40 °C. However, some may be able to withstand higher temperatures, so YMMV. M8E, on the other hand, doesn't seem to be as strongly temperature sensitive, demonstrated by
buildzoid.
I have tRFC at 300 for DDR4-4000, 1.5Volts and its fine over 50c.
With B-die and AMD. 1.6Volts is were it gets bad. tRFC timings are important if the RAM heats up a lot. As the guide states best temps between 30-40c I use a fan but I pass tests in the 50c+ range with the same timings. Dust is only a real issue on the DIMMs if you run a Fan. Also some IC's degrade above 1.35 volts.
If you look at the information in the first post you can see his memory temps are lower than mine. Between 40-46c. His DRAM is 1.44 volts and mine is 1.45 volts stock. His tRFC is 500 which is far higher than my 300 (lower is harder on the RAM). This is the main temp affected timing.
You are right bout the dust but I am not sure its his issue at the moment.