Quote from: Dallski on October 18, 2014, 03:01:57 AM

Quote from: MissouriMiner on October 17, 2014, 08:36:42 PM

Quote from: yslyung on October 17, 2014, 08:02:13 PM

Quote from: MissouriMiner on October 17, 2014, 05:36:21 PM

Quote from: OrangeGator on October 17, 2014, 05:19:35 PM

Yeah, I know. I tried them with 1 miner per EVGA psu, plus the third on an old Corsair TX750. Still no luck overclocking. I am using a Kill a Watt, and am measuring 1080W at the wall at stock speeds. The max it ever hit was 1150W when trying to overclock.

Quote from: bspurloc on October 17, 2014, 02:01:45 PM

Well how are you going to overclock 3 S3's with 2 power supplies that can't supply enough current to do it??
Each S3 at 250 will draw 400+ watts.
I would connect just 1 or 2 and try to overclock them 243 and 250. if they work then it is what I noted, the power supplies cant supply the amps needed for 3 overclocked

Here are some stats I gathered, just for information sharing. As many are aware, the power from the wall depends on PSU efficiency and used capacity (% of MAX). A single 1000W PSU powering 2x S3+'s will draw more power from the wall than 2 separate same model 1000W PSU's. The higher the PSU capacity , the lower the efficiency.

MHz Setting   Avg Gh/s   Watts      "Efficiency W/Gh"      PSU Model

225            453          400          0.88                  1000W Coolmax, 80 Plus Bronze

225            453          365          0.81                  1050W Cougar GX1050, 80 Plus Gold

225            453          390          0.86                  1200W Coolmax, 80 Plus Gold
237            470          415          0.88                  (Running 2x S3+, Values are per S3+)
250            500          445          0.89

225            453          365          0.81                  1300W Rosewill Lightening, 80 Plus Gold
237            475          385          0.81                  (Running 2x S3+, Values are per S3+)
250            500          405          0.81

thx for sharing, might be a noob question ... if power is 230V compared to 110V would it make a difference ? i think it would.

It doesn't matter. This is regarding Watts, which is constant between 110V and 220V. With 220V, you are using double the Volts at half the Amps. But the Watts is the same. Volts * Amps = Watts

Actually, it has been shown that power supplies using 208-240V rather than 110/120V are 1% more efficient. Aside from 110/220, there are two other important efficiency factors: (1) Ambient Temperature and (2) Percentage of PSU capacity used. With the first, I have seen a 1.3% difference in power consumption between 60*F and 80*F ambient temperatures, mostly due to the fans having to work more or less. With the percentage of PSU capacity used, the sweet spot of most PSU's is 40%. That is where they are most efficient. Efficiency curves are not flat. And Power Supply ratings are based on output, not input, so you can have a 500W bronze PSU pull 600W at the wall. Try actually running one S3 on that Rosewill Lightning and see if you can still hit those same numbers. Then try running three. I bet you will have different results.

Most power supplies will be about 2% more efficient at 230v vs. 115v (actually a range of 110v to 120v). My Gold power supply is about 90.8% efficient at 120v and 92.7% at 230v according to the power supply display (running 2 S3+'s at 237.5M = about 778watts on the ThorTech Thunderbolt Plus 1200w power supply display). Anyone done a graph on what the peak efficiency of the S3 is (from 100M-250M)? I've got all the equipment here to do the tests that I was thinking of doing this weekend. I've got 2 S3+'s hooked up the a Corsair AX1500i Titanium power supply (the most efficient power supply you can buy) and with 2 it's at about its peak efficiency point of 50-60% load. I've got a 3000watt step of voltage converter/transformer (problem in the U.S. is even if the 230v is more efficient, you have to convert it here and that takes up some loss in efficiency vs. those where it's 230v at the wall. My 3,000watt step up converter takes about 40watts at idle and goes down to 20watts when using with the 2 S3+'s at 237.5M. So the power for the system went from 820watts at the wall to 840watts with the 230v step up converter was placed in the line). I've also got a 120v kill-a-watt (for power at the wall) and a 230v kill-a-watt (arrived today, for power after the 230v step up converter/transformer) as well as a 1,000watt/1,500VA sine wave UPS (230v version). Should give a pretty accurate reading for an efficiency graph if someone wants to put one together.