Now tweaked a bit and it survives Prime95 blend 768k for 15 minutes, after that errors occur. I didn't tweak the sub timings, but the "other" settings, like asyc (sic!) latency and drive strength settings. Now I need to check for the sub timings. And I think I need to set tRP to 4. Also Vdimm is set to auto, which seems to be 2.5V. At least it is more stable than VDimm set to 2.6V
Oh, and everything is without ECC.
No amount of tweaking made the memory run stable in Prime95. Even 3-4-4-8 and relaxing sub timings didn't help.
Now I do what herm did in the beginning: Enabling ECC
Everything else untouched, the DIMMs survive the 768k test for 15 minutes without any errors. Now I'm trying 3-3-3-8. Everything with Vdimm set to auto (i think it's 2.5V, but I can't be sure). Maybe there is a chance to get this f*cking RAM past 230MHz Edited by seaFs - 8/3/16 at 1:50pm