Quote from: storm2k5 on February 19, 2014, 09:03:08 PM

Quote from: mgio on February 19, 2014, 08:37:55 PM

Well right now it is only mining at 230 GH/s and my other BJ does 430 GH/s so its a pretty big loss. I should be able to cover 6 days of not mining in a little over a week when I get it back. I don't want to overclock it for fear they will claim that I broke it and voided the warranty.

How high were you able to overclock it? What other tweaks were you able to do?

I have a full die not working.
This is what I tried:
-cgminer 3.09hf2 / RPi @550: 255ghps
-cgminer 3.11 / Win7 @ 550: 255ghps but very weird effects on local output of hash rate
-cgminer 3.12.3 / Win7 @ 550: 255ghps but very weird effects on local output of hash rate + USB disconnects
-cgminer 3.11 @ 634: 315ghps but very weird effects on local output of hash rate
-bfgminer 3.10 @ stock: 295ghps 5.7% HW but no overclocking possible in official build
-bfgminer compiled from git @stock: 300ghps 4.5% HW
-bfgminer compiled from git @670: 375ghps 4.5% HW 88°C / Room 22°C

I think bfgminer handles dead cores/full dies better, thats where the perf increase towards cgminer comes from. The fact I can go up to 670 (and higher, didn't try) probably shows that the overclocking limit is the Vregs on the board and not the silicone (with only 3 dies working, you need 1/4 less power, so you can overclock the 3 dies alot more) Someone else reported better OC capability by cooling the Vreg heatsinks with additional fans, so that kinda fits the picture.
Hope this helps, I posted the bfgminer version with overclocking enabled a couple posts above, and I also posted the driver you will need for it (windows)

how did you test for the bad core? my hash rate goes from 800 ghps to 14 ghps. Very unstable keeps restarting because it runs at less than 100 ghps for 5 min.