I have  4x NewPacs and 1 Compac (diferent hubs) running 4.12 on Windows 10

Bizarrely the 4 Newpacs all run at full tilt with one hub plugged in,  and the Compac is fine on the other hub by itself.

When both hubs are plugged in one of the Newpacs performs as follows:

 0: GSH 10036077: BM1387:02+ 393.75MHz T:394 P:392 (95:48)  | 53.1% WU: 61% | 48.15G / 54.38Gh/s WU: 759.7/m

if I reset the device it goes back up to speed.. however after a few hours it drops again.  I have 4 Arctic USB fans blowing on them so temp shouldn't be an issue.

I see that the frequency has been automatically throttled back slightly...

My batch file....

cgminer.exe -o stratum+tcp://solo.ckpool.org:3333 --gekko-newpac-freq 400 --gekko-compacf-freq 450 --gekko-start-freq 300 --gekko-tune-up 85 -u bc1q5mev0ddxan2zspas0t7wgl3ftxxrhq67hn2d53.0 -p x --suggest-diff 1024


Any suggestions?