Here's the latest figures, now running a 20Mhz crystal on ICA 7 which is stable at 406.2 MHash with ASIC powered externally with 1.7V @ 3.96A. ICA 6 is the stock reference running at 333MHash.
bfgminer version 3.1.3 - Started: [2013-08-15 20:58:51] - [ 0 days 03:00:24]
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5s: 2.66 avg: 3.65 u: 4.37 Gh/s | A:2752 R:30+0(1.1%) HW:92/.82%
ST: 4 GF: 0 NB: 21 AS: 1 RF: 0 E: 9.66 U:15.3/m BS:36.6k
Block: ...5e0f8f39 #252279 Diff:50.8M (363.7Th/s) Started: [23:45:10]
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ICA 0: | 960.4/364.6/422.2Mh/s | A:266 R:4+0(1.5%) HW:10/.88%
ICA 1: | 543.2/363.7/393.6Mh/s | A:248 R:1+0(.40%) HW:13/1.2%
ICA 2: | 245.2/364.5/477.8Mh/s | A:301 R:1+0(.33%) HW:10/.85%
ICA 3: | 423.3/364.2/455.5Mh/s | A:287 R:3+0(1.0%) HW:10/.89%
ICA 4: | 581.1/364.4/447.6Mh/s | A:282 R:6+0(2.1%) HW:10/.91%
ICA 5: | 348.0/361.7/441.3Mh/s | A:278 R:1+0(.36%) HW: 9/.84%
ICA 6: | 394.9/333.8/296.8Mh/s | A:187 R:3+0(1.6%) HW: 7/.85%
ICA 7: | 294.3/406.2/563.5Mh/s | A:355 R:4+0(1.1%) HW:11/.79%
ICA 8: | 532.0/363.8/460.3Mh/s | A:290 R:5+0(1.7%) HW: 5/.44%
ICA 9: | 239.9/365.9/411.1Mh/s | A:259 R:2+0(.77%) HW: 7/.61%
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I've bought a few crystals and heatsinks too many so if anyone wants me to upgrade their units to either 16 or 20 mhz speeds I'd be happy to do it.
2 day maximum working turnaround and high quality soldering done with an SMD rework station with all components, heatsinks and external power supplies (if necessary) included. Please PM me if interested.
Do you get higher error rates at lower voltages? How are your temps looking? 1.7v is dangerously close to the 1.8v limit. Let us know how these perform long term.
In regards to powering these things, i was planning to solder a molex plug on the back end of the usb miner so i could simply plug them in and out of a standard pc power supply. Then, for the data, use usb extensions with the power line cut. Hopefully, using that method would allow quite a few overclocked miners at the same time.
Of course, i'm thinking out loud here so if anyone see any trouble with that, please let us know.
I think this is quite a good idea I may do this myself. I have my miners mining away @ 447Mhs @ 1.2v with the stock voltage regulators. I thought I had killed one but It's now working after it cooled down from the 18 and 20Mhz attempts.