Your symptoms sound like an intermittent fault with one of your memory modules. As you have plenty, I'd suggest taking one module out and letting the system run for a few days. If you don't get a BSOD, that's the faulty memory module. If you do, replace the one you took out and remove another one. Repeat until you identify the faulty module. It's nothing to do with QVL, although memory from suppliers like Crucial tends to be of better quality than 'no name' memory. My son had a similar problem with his PC, and the memory module eventually failed completely, preventing it from booting.
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