Quote from: philipma1957 on March 11, 2014, 12:29:30 PM

Quote from: HypnoticGuy on March 11, 2014, 12:45:42 AM

FYI I just got one today, after 20 minutes it gets to 2.06 Gh/s with clock=x0981, and it runs great with zero errors and zero rejects.

When I overclock to 0A18, which on the U1 is 2.2 Gh/s, after running for 20 minutes it only gets up to 2.12 Gh/s with 0 rejects and 5.41% error rate.

So, it seems like 2.0 Gh/s is the max you can expect with low error rate.

I haven't been able to find a user manual on the U2 yet however, and the clock parameters for overclocking may be totally different than what was used for the U1.

I have emailed Antmain about this but have not heard back yet.

Edited to add:

After 2 hours it's hashing at 2.063 Gh/s, with zero rejects and zero H/W errors.

Also, FYI my USB power is not an issue. I am getting my +5V from the molex connector of an ATX PSU at 32Amps.

if you had a u-1 and a u-2 to compare you could see if it has the same resistor controlling the voltage allowed to the chip.

Based on you tests so far I think it is the same.

which makes the older sticks better in one way the will fit on a tighter hub.
the newer sticks may not need fans.
So if you have a choice of sticks some may prefer the new for the silence offered. Some may prefer the old for the smaller size.

The resistors are so tiny it's hard to see, however I heard back from Antmain and they say the overclock hardware mod is the same for the U1 and U2, so I guess that answers your question.

It would seem as if the only difference between the U1 and U2 is the heat sink, making the U2 stable at 2.0 Gh/s without a need for additional cooling.