L310B491 is a not bad batch to look for. It scales with cold and handpicking on AC seems to be the write method for this batch.
5 GHz 4/8 @ 1.35v @ 6.7 GHz CPU-Z one core, 1 core boot 6.5 GHz @ 1.9v to OS, can't run spi 32M
5 GHz 4/8 @ 1.275v @ CPU-Z not tested though, but boots 6.5 GHz 4 core @ 1.8v and enters OS and runs SPI 32M
from this batch cpu which can't do 5 GHz 4/8 air is a very bad one on LN2
Have fun!
BTW
But this batch is fragile so be gentle with those cpus