AntMiner S1 Underclocking, a thorough discussion

[wpgdeez]

I still got to get around to underclocking mine so I can turn them back on!

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[intobit459]

    

Who is running at .75v?

[sidehack]

Sometime when I have time I might crank mine down around 0.8, but right now they're still coming out ahead.

Also, I'm hoping to do a full workup on AM Tubes next week.

[philipma1957]

nice thread can't believe I have not read it until today.

[klondike_bar]

   

Who is running at .75v?

Ive got decent stability around 0.75-0.77V / 200-206MHz / TO=55 works and 90-100% of chips run well to produce 95-105GH/S1

going any lower to 0.7-0.74V / 193-200MHz / TO=50-60    seems to produce mixed results, usually 50-80%  of the chips function and I have around 50-75GH/S1

going any higher to 0.78-0.82V / 200-215MHz / TO=50-60    seems to produce decent results, generally 70-90% of the chips function and I have around 95-115GH/S1


i think these dont necessarily run well at the same settings as the S2 for whatever reason. running around 0.75-0.78V and 200MHz is probably the sweet spot

[sidehack]

Just as a note, I'm starting an analysis on ASICMiner Tubes to see where they'll go. Our facility has hosted Tubes in the past, so I'm thinking about if the numbers look good, offering to undervolt for free any Tubes people want to send for hosting. They're getting to end-of-life definitely, but once we've completed our electrical upgrade and shift to the new rate schedule, all hardware will be $0.10/KWh flat. If I can get Tubes to put up decently in the 0.5-0.7W/GH area it might be worth looking into.

I should have results posted in a few days once I'm done running the jillion tests.

[Trends]

I'm looking forward to your ASICMiner results sidehack, I under & over volted Rockminers RK/R3 boards and could not find any significant gh/w benefit worth chasing.

Trends

[sidehack]

If it's there I'll find it.

Also noteworthy, the BTCGarden AM-V1 blades use almost identical VRM circuitry but two chips per instead of three, so an optimal point on a Tube should result in a slightly more efficient point (reduced current means reduced resistive losses in the regulator) on one of them with the same hardware mod. I may do a full analysis of a Garden board for comparison, if I have time.

[kano]

Someone linked this thread elsewhere so I thought I may as well add that I released a current master cgminer release 4.9.1a for the S1
https://github.com/kanoi/cgminer-binaries/tree/master/AntS1