I have 650W and 700W supplies who stop working when mining with 2 1080ti's on 100% power limit without other systems (no hdd/cpu/mobo).
Get 750W or more, gold or better.
.....I know what all of you are saying. I wouldn't be mining at 100% power limit. More like 75%, ~185W per card.
185W
185W
100W+
---------
470W......
It's not always like this.
Take a look at the
PSU's Label, the 12v rail (yellow) was indicated with 2 wattage.
The 1st one would be for the 4Pin Molex, sata, processor and MotherBoard 12volts.
The Second was for the 6Pin or 8Pin Connectors.
Although, cheap and substandard power supplies does not have this kind of feature.
Getting the total power consumption of all the component wasn't the correct formula.My Gaming Rig PSU for example, the label said 12v max 100W and another 12v max 350W.
The 350W was allotted only for the GPU's supplementary Power. This is where you will base on how many cards you can power.
A different scenario when you're using a
4pin Molex to 8/6-pin Adapter. It will get its power from the other rail.
Seasonic Prime power supplies are a single-rail design, there is no issue with "split rails" like on the CHEAP power supply you are talking about.
For that matter, every power supply that Seasonic has made and sold under it's own name for YEARS have been of the "big single +12V rail, then convert the OTHER voltages FROM that big +12V rail" design.
EVGA SC 1080 ti cards should be making quite a bit more than $1-2 a day net after electric right now via Nicehash - a quick check on whattomine shows Nicehash best algorithm listed on a single 1080 ti having a NET PROFIT (at my very low electric cost) of about $8/day if running it for high hashrate.
To MrNice9uy:
OF COURSE your core clock speeds drop when you lower the TDP - boost clock is limited by several factors, the biggest one of them is the power available to run the card and GPU on.
It also drops temps, as the card doesn't have as much power to dissipate, IF the fans are set at a "fixed" speed - will still drop even on a "fan curve" but not as much since the fans will slow down some.
The reasons a lot of us set the TDP lower are multiple:
1) Better efficiency, so we can run MORE cards on the same amount of power and end up generating more coin per watt.
Mostly applies to folks that are at or close to their power limit for their mining area, or to folks with VERY VERY HIGH electric rates.
1080 ti in specific, 250 watt TDP MIGHT genrerate as high as 780 sol/s on a very good cooling card like an Aorus, but at 150 watt TDP the same card still generates around 620 - drop the power 40% only lose 20% income.
Cards with lesser cooling will lose less hashrate, as they will still probably manage the 620 "low power" hashrate but WON'T manage the 780 at high power.
2) Lower temperatures, for better lifetime of the card and the fans on it.
3) Some folks mine in areas it gets HOT AND HUMID in the summer, at which point they HAVE to drop the TDP to get the card to stay cool enough to run at all or to avoid temp-limit throttling.
It's a bad idea to assume standard "mechanical" Air Conditioning as that stuff adds 30-40% to your ELECTRIC USAGE to keep your rigs cool.
In my case, it's also due to infrastructure limitations - the place I'm in has a lot of standard 117 VAC 15 amp "duplex" outlets, but I'm not allowed to "rewire" the place, so building rigs that can run at 6 amps draw using 5 1070 ti cards set for EFFICIENT mining allows me to make the best usage of the available power without pushing the wiring past the 80% derate for 24/7 operation that the NEC requires for SAFETY reasons.
