odd speeds for my antminers u1

[liamf91]

good evening guys.

i am pretty new to mining, (yes i know its a little late, oh well). i bought a u1 a week ago (1.6gh to 2.2gh). it worked perfectly with cgminer. so i bought another for more speed. i had trouble setting up cgminer to use both miners so i switched to bfgminer instead, which can detect and use both miners okay.

my issue is that it is not achieving the speeds that its set up for. i have included a screenshot of the average speeds its running at. (please note that the miners are not on a usb hub, but on two separate usb slots on the pc front):

http://i59.tinypic.com/2pt7wiu.jpg

also here are my bfgminer command line settings:
B:\bfgminer\bfgminer.exe -o [pool:port] -u [worker] -p [password] -S antminer:all --set-device antminer:clock=x0A81

The clock is sett to 0A81 = 2.2gh. i do have good cooling so no issue there. i have tested each miners separately and both work fine.

any ideas?

plus any help with setting cgminer for multi miners would be great

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[liamf91]

any help?

[liamf91]

any help?

nothing? someone must have had a similar issue

[lowbander80]

check if your second miner has good connection with the USB post to see if you can drag enough power out of the USB port

[liamf91]

all seems fine with connects. both miners are fine. i have tried on multi ports. both separately on the same ports and both together on different ports. no idea why :/

[chup]

USB ports are not supplying enough power. Put them on powered USB hub and You will have no problems at all... U1s are pulling much more power when overclocked than power specified by USB 2.0 standard...

[liamf91]

i did try with a hub to no luck.. i have bought a new hub for a raspberry pi miner project im doing. i know that works so must be as you said, not enough power.

[OliRS]

Other things to check are:

Heatsink bolts tight?

Also don't use the highest clock, in my experience with many U1's it just gives you a shed load of errors. I get a steady 2.0 GH/s off all my U1's using 0981 and goes days with literally no errors.

Was the USB hub you tried powered or passive? Get a powered hub and you'll be fine.

[liamf91]

it was powered. but i think its was faulty. the new one seems to work fine.

I have finished my Pi miner, seems to be working just fine at the moment. i can keep it running all day and night with minimal power consumption. more U1 miners will be bought soon enough i can get a 0.00010176 BTC return on the two miners for 2 hours. on shush's pool. with my experience i will not get that ever two hours... only when a new block is confirmed. but still a good return.

hopefully i can get at least double of that return with 4 or more U1's