Quote from: chromosoma on January 12, 2014, 12:22:16 AM

ok
New results from overclocking attempts:

I upgraded my 4 Anminers with 10K and 2.5K Resistors, and connected only one antminer first.
Finaly i managed to get very stable 2,4-2,5 GHS from one miner.
The overclocking procedure is not straight forward.

The antminer SilLab microcontroller seems to store some kind of calibration table , which he uses to control PWM of the DC/DC converter and adjust the voltage for TXO ( Frequency).
After you change the voltage output of the DC/DC converter those calibration values didn't match with reality, so you just cant start with high frequencies, the error is too high.
Instead start with lowers GHS possible: 1.4 GHS.
Wait until it stabilize, and increase the frequency by one value.
Step by step I managed to run Antimner at 0B81, which gave me about 2,5 GHS.

After i plugged the second calibrated miner into USB3.0 HUB (4A max), the speed of the 1st miner gone to 2.1 GHS, and the second one gave 1.9 GHS. The third miner just gone zombie...
Seems like there is not enough power? But funny enough I got the same 2.5 GHS result from USB2.0 PC port.... so current shouldn't be a problem here, probably....

I am, not quite sure WTF is wrong with AntimnerU1. Maybe some kind of connection/synchronisation errors with cgminer...

I tried to run BFG miner, but it couldnt find any device at all....even after i deinstall zadig drivers.
Moreover CGMINER cant find a device directly from USB3.0 (my USB3.0 hub is connected to the USB2.0 Port) port.

I will purchase a PCI USB2.0 extension card with separate powersupply from the main PSU. Costs only 10 Euro, so i give it a try, in case there is not enough current...

Seems like there is not enough power- IMHO this is answer, maby hub (dead on arrival) are consume large amounts of power.