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Topic: S3+ (BM1382) Overclocking with voltage setting - page 9. (Read 28757 times)

legendary
Activity: 1876
Merit: 1000
Are S3's really have voltage change capability?
Anyone checked actual wattage from the wall?

Yes, i did, and did NOT see the actually wattage change.
hero member
Activity: 672
Merit: 500
Are S3's really have voltage change capability?
Anyone checked actual wattage from the wall?
hero member
Activity: 518
Merit: 500
Does the voltage reset to default after reboot?
It does not reset to default so long as you save it once you have set it. I simply do a Save & Apply after setting and do not need to reboot as that action restarts cgminer.
member
Activity: 89
Merit: 10
Does the voltage reset to default after reboot?
hero member
Activity: 857
Merit: 1000
Anger is a gift.
Pete, one day I will find you and give you the biggest high five ever. Thanks for the guide man!!!
Pete ...!? You talking to me? High fives all over then, and the pleasure is all mine.
I also noticed that the default voltage setting that bitmain ship with is 0725 but there is no mention of any 5 thousandth in the datasheet, so naturally, I tried it on one of my rigs that I had running at 0750 (aka tried 0755) ...... not bad!

Shit, sorry. I always read it wrong...
hero member
Activity: 518
Merit: 500
Pete, one day I will find you and give you the biggest high five ever. Thanks for the guide man!!!
Pete ...!? You talking to me? High fives all over then, and the pleasure is all mine.
I also noticed that the default voltage setting that bitmain ship with is 0725 but there is no mention of any 5 thousandth in the datasheet, so naturally, I tried it on one of my rigs that I had running at 0750 (aka tried 0755) ...... not bad!
hero member
Activity: 857
Merit: 1000
Anger is a gift.
Pete, one day I will find you and give you the biggest high five ever. Thanks for the guide man!!!
hero member
Activity: 518
Merit: 500
Sorry for the silly question but I just put the voltage setting in the voltage box under the drop down for the Frequency, correct?  
No such thing as a silly question, simply a question.
Yes, type the voltage setting inside that box and click Save & Apply (cgminer will restart after that and no need to reboot), else if you click Save, the setting will be applied next time you reboot the rig.
member
Activity: 89
Merit: 10
Sorry for the silly question but I just put the voltage setting in the voltage box under the drop down for the Frequency, correct? 
full member
Activity: 168
Merit: 100
Hindsight, my friend...history makes for good lessons...
hero member
Activity: 518
Merit: 500
Hmm....I have mine set to 0850 right now...maybe I will me the adjustment per your recommendation tonight.  Is there a notable hash increase?
Running at a freq of 262.5 with a voltage setting of 0850 will not be as efficient as running with a voltage setting of 0750, as you'll get more HW errors. At the very worst though (assuming you have an an adequate PSU), you'll be wasting power as the combined wattage is 544W whereas at 0750 it is ~294W. (note the wattage I mention here is theoretical and will actually be more!)

Classically, that is what we have been doing wrong all along, i.e running / overclocking the rigs with different frequencies at the same voltage setting! It should have been setting a voltage for a range of frequencies, but now we are wiser.
full member
Activity: 168
Merit: 100
If you insist on splitting hairs, then it'd be best to be exact on how much more (specific) wattage draw there is between freqs 250 and 262.5 at the suggested 0.75V
Cant say for sure, but it would be approximately 262.5/250 = 5% higher. difference between ~400W and ~420w

From my calculations (excluding power consumption of other bits, e.g fans and dc/dc converters), I have:

For freq 250 32 chips @ 0.75v 12.24A = 293.76 Watts
So, by your linear model: 262.5 / 250 = 1.05 (factored to the amperage) =>12.852
For freq 262.5 32chips @ 0.75v 12.852A = 308.448 Watts

Making a grand difference of 14.68 Watts. Tell me if I am splitting hairs here ... I mean to say, even 20 watts is not exactly pushing the envelope!

Dude whatever as long as my units aren't maxing out my 750W corsairs at the wall I could care less.

My thoughts exactly .... though I blew up my 550W rated PSU running my rig @ 0.85v !

Hmm....I have mine set to 0850 right now...maybe I will me the adjustment per your recommendation tonight.  Is there a notable hash increase?
hero member
Activity: 518
Merit: 500
Updated OP with 2 days screenshot running freq 262.5 @ 0.75v
hero member
Activity: 518
Merit: 500
If you insist on splitting hairs, then it'd be best to be exact on how much more (specific) wattage draw there is between freqs 250 and 262.5 at the suggested 0.75V
Cant say for sure, but it would be approximately 262.5/250 = 5% higher. difference between ~400W and ~420w

From my calculations (excluding power consumption of other bits, e.g fans and dc/dc converters), I have:

For freq 250 32 chips @ 0.75v 12.24A = 293.76 Watts
So, by your linear model: 262.5 / 250 = 1.05 (factored to the amperage) =>12.852
For freq 262.5 32chips @ 0.75v 12.852A = 308.448 Watts

Making a grand difference of 14.68 Watts. Tell me if I am splitting hairs here ... I mean to say, even 20 watts is not exactly pushing the envelope!

Dude whatever as long as my units aren't maxing out my 750W corsairs at the wall I could care less.

My thoughts exactly .... though I blew up my 550W rated PSU running my rig @ 0.85v !
full member
Activity: 168
Merit: 100
Dude whatever as long as my units aren't maxing out my 750W corsairs at the wall I could care less.
legendary
Activity: 2114
Merit: 1005
ASIC Wannabe
if you are running at a freq of 250, there's no harm at all in notching it up to 262.5 since it is the same voltage setting (and thus same wattage draw only run faster!)

higher frequency, same voltage = higher wattage draw.

w/gh will not change significantly, but the power raw at the wall will increase (almost) linearly with the frequency at any specific voltage
If you insist on splitting hairs, then it'd be best to be exact on how much more (specific) wattage draw there is between freqs 250 and 262.5 at the suggested 0.75V

Cant say for sure, but it would be approximately 262.5/250 = 5% higher. difference between ~400W and ~420w
hero member
Activity: 518
Merit: 500
I am going to go buy some thermal paste tonight or tomorrow and then I will max out the OC on my units.  Has anyone successfully actually gone to 400 MHz sustainably?
I'd have liked to try that but the datasheet does not provide a voltage setting for that frequency, it literally only provides the four in the first table of the opening post! Also, the largest PSU I have available to run the S3 rigs is a measly 670W.
hero member
Activity: 518
Merit: 500
if you are running at a freq of 250, there's no harm at all in notching it up to 262.5 since it is the same voltage setting (and thus same wattage draw only run faster!)

higher frequency, same voltage = higher wattage draw.

w/gh will not change significantly, but the power raw at the wall will increase (almost) linearly with the frequency at any specific voltage
If you insist on splitting hairs, then it'd be best to be exact on how much more (specific) wattage draw there is between freqs 250 and 262.5 at the suggested 0.75V
full member
Activity: 168
Merit: 100
I am going to go buy some thermal paste tonight or tomorrow and then I will max out the OC on my units.  Has anyone successfully actually gone to 400 MHz sustainably?
legendary
Activity: 2114
Merit: 1005
ASIC Wannabe
if you are running at a freq of 250, there's no harm at all in notching it up to 262.5 since it is the same voltage setting (and thus same wattage draw only run faster!)

higher frequency, same voltage = higher wattage draw.

w/gh will not change significantly, but the power raw at the wall will increase (almost) linearly with the frequency at any specific voltage
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