Just as a note, all sticks are tested for a minimum of 12 hours at 400MHz and must average at least 220GH (80% speed) during this test to be cleared for shipping.

These sticks don't run well at low speeds. You don't buy a Ferrari to drive Miss Daisy. These chips were made to go FAST and they tend to choke while slow. The higher the clock, if the voltage is stable, the closer they'll run to true. If you want to overclock one but it's stalling in low speeds, you need to --gekko-start-freq to a higher speed, and if it still has trouble stalling, --gekko-tune-up to a lower step threshold.

For instance, I noticed some sticks have trouble below 200MHz and some have trouble below 300. For most, 300MHz is past the breakover point where they start running well. Therefore my test script includes:

--gekko-compacf-freq 400 --gekko-start-freq 300 --gekko-tune-up 85

which means it targets 400MHz, starts ramping from 300MHz (instead of the default 200), and will step up when the measured hashrate breaks 85% of expected (instead of the default ...90-95%?)

So Sledge, it's likely that your sticks are not faulty at all. It's more likely that you need to adjust command line parameters to force it past the sluggy bottom end and into the smoother high revs. If it doesn't level out above 300-400MHz, that's when adjusting the volt screw could start to make a difference.