Found a couple batches that are very reliable at reaching those settings
3918A497, 3914A740 for i7 920
3918A533 for Xeon W3520
3914A739 for i7 975 (my best is 4500 1.23V, but it “only” does a bit over 5.5 on cold sadly since it has a bad coldbehavior - for this batchrange - of -130 sweetspot. My W3520 is happy at fullpot and my other 975 (5.8 valid) at -160.)
QR code range for these chips is N3924-N3926, with almost every single chip I’ve found or heard of in this range being 4500 <1.25V and most chips easily doing 5500 on ln2, as long as bclk plays along.
looking at LN2 results and old forum threads I’m fairly certain W3570s of these batches certainly exist too, unsure about W3540. I’ve tried finding a 950 for years in this range but without luck. Since I’ve stopped actively looking, I no longer feel like its right to keep this info to myself.