That’s only for open world maps, many games where the placement of rocks and trees is something that’s subject to miniscule changes for balance reasons.

Sadly most good tools are windows only but: OCCT, karhu Ram test and testmem5 (anta extreme config) Are all good choices, but id usually recommend running more than 1.

Memtest is quite shit, seriously unstable ram will still pass. If it doesn’t pass memtest it’s actually dead.

Thermal expansion and contraction is what can lead to the die cracking. Not really a problem on anything other than laptops with shitty coolers which can reach 110C.