Hi there

 

im really dumb im understanding how to calculate wattage usage

so this is a south african forum

i hope local can help me with this math

so lets say current electrical unit costs R2.20 in my area

i believe kwh has to be calculated

so i have 2 Graphics cards

one is rated at 150 watts - gtx 1070

other at 350 watts - rtx 3080ti

lets say i game 3 hours a day which is 90 hours a month

i want to know how much does this cost to run each gpu

there has to be a way to work this out

i see newer gpus use more wattage

what i dont understand is if each gpu runs at 1mv {actually the 350watt draws less at 0.900]

how is it possible for one gpu to use more power lest the pcb board draws more from the wall but never uses it

which is a waste in my mind

A watt is an instaneous measurement. What we get billed in is kWh (kilkowatt hours). If you consume one kilowatt for one hour that is one kWh and that costs you R2.20 in your example. So 150/1000*2.20 will give you the cost of running that first GPU for one hour. Assuming the draw is constantly 150W, which is an assumption I don't want to make. A GPU can be working hard some times, not so hard at others. 150W is probably the consumption when it is working hard.

But wait! There's more. 

Those GPUs are fed by the power supply in your computer. That will be not be 100% efficient (IE if it consumes 100W, the output will be less than 100W). So to really get the right figure we need to factor in those losses.

And the billing will not be constant. Where I live, and on my tariff, it is 2.09 inclusive of VAT for the first 350 kWh in a month. Thereafter the tariff increases as I exceed 350 kWh, 500kWh etc.

But look at my first paragrapht and you can get a ballpark figure. Add on 5% for losses in the PSU etc.

43 minutes ago, Dennis said:

what i dont understand is if each gpu runs at 1mv {actually the 350watt draws less at 0.900]

they don't run at 1mV, but even if they did, W = 350, if V really were 0.001, then the current would have to be 350 / 0.001 = 350 000 Ampere... I think not...

the GPU's usually consume their current at 12V from the PC PSU's side and also use 3.3V and possibly 5V a lower current levels for memory and logic level functions, the GPU will also run at lower Voltages, but thats converter locally since the high currents should be handled locally and not via cables and connectors, either which way, Watt is Voltage times Current aka W = V * I or V * A

if you run a GPU that averages 350W for 90 hours, that is 35 000 - 3500 = 31 500W aka 31.5kW consumption for the month... at ZAR 2.20 per kW that then is ZAR 69.30, but you are only looking at the GPU of 350W, the PC itself is probably consuming at least this amount as well, if not more...

lets assume the PC consumes (400Wh + the respective GPU) times 3 hours times 2.20 ZAR / 1000 to convert Watt to kiloWatt to tie in with the 2.20/kW ... so for the:
GTX1070 we have (150 + 400) x 3 x 2.20 / 1000 = R 3.63 per 3 hour gaming day
RTX3080Ti we have (350 + 400) x 3 x 2.20 / 1000 = R 4.95 per 3 hour gaming day

the ZAR amounts sound little, but in our current rolling blackout scenario you actually need to look at the power consumption... specially if you start at running off inverters and batteries...

more modern GPUs & CPUs are manufactured with smaller and smaller fabrication techniques which makes the gates etc. smaller than ever before which reduces the power consumption, so things are getting better on that front, however, we also thirst for more processing power.... if you look at a Raspberry Pi 4, for instance this would have kicked a Pentium CPU based machines ass right off the planet in 1995, yet the Pentium machine was consuming probably3 to 400W at least and the Pi 4 which also has 4 CPU cores as opposed to the single core for the Pentium, the whole Pi probably tops out at 5Ampere consumption times 5Volt = 25W !!!!

You need to understand that even if you game your gpu never get used 100%, it might be 50% to 20% in dota and then 90% in a othergame.

 

So lets worse case you do use the gpu at 100% lets work it out:

150watts x90hours  =13 500watts that works out to 13.5kw so thats about R29

on the 3080ti  350x90=31 500 =31.5kw @R2.20 = R69.30

 

About the 1v the 1070 has a gpu die size of (GeForce GTX 1070. The GP104 graphics processor is a large chip with a die area of 314 mm² and 7,200 million transistors.)

vs

3080 the GA102 graphics processor is a large chip with a die area of 628 mm² and 28,300 million transistors.

 

so the 3080 has way more stuff that draws power

this kinda maths of electricty costs is hard for me

so i have been gaming on the 1070 150watt rated for many years

so my current electrical bill is like R600 a month

i do game often

but as i have tested in game using MSI Afterburner it displays on screen the wattage of the gpu

so this 1070 i have seems to hover from 130-160 continuesly depending on game

so if i spent R6oo i get 273 units which is roughly R2.20 per unit

i use on average 10 units a day

so MSI afterburner shows the cores of the gpu using 1030mv during gaming

and when idle not gaming is at 0,625mv

the 3080ti uses average 900mv during gaming

 

i dont understand if it uses 1mv how can one gpu draw more power at 0.900mv

allthough the 3080 is on a newer node of 8nm

 

thats why i want to know will my electrical bill increase by much if i use the 3080ti at 350 watts

 

so thanks for the help so far

i woud like to ask is the 2 above replies the same in correctness of money spent per hour 

Edited February 8, 20233 yr by Dennis

1 hour ago, Dennis said:

this kinda maths of electricty costs is hard for me

so i have been gaming on the 1070 150watt rated for many years

so my current electrical bill is like R600 a month

i do game often

but as i have tested in game using MSI Afterburner it displays on screen the wattage of the gpu

so this 1070 i have seems to hover from 130-160 continuesly depending on game

so if i spent R6oo i get 273 units which is roughly R2.20 per unit

i use on average 10 units a day

so MSI afterburner shows the cores of the gpu using 1030mv during gaming

and when idle not gaming is at 0,625mv

the 3080ti uses average 900mv during gaming

 

i dont understand if it uses 1mv how can one gpu draw more power at 0.900mv

allthough the 3080 is on a newer node of 8nm

 

thats why i want to know will my electrical bill increase by much if i use the 3080ti at 350 watts

 

so thanks for the help so far

i woud like to ask is the 2 above replies the same in correctness of money spent per hour 

You need to remember volts is not how much power a gpu draws, WATTS is, that is why the 3080 is 350watts

Just like a hairdryer is 220v but its 2000watts and a light bulb is 220v but its 50watts max

 

 

 

 

ok so far thanks to everyone

so if im correwct here

it seems that the 1070 uses 33 cents an hour for gaming

and using the 3080 would use 77 cents an hour

 

this would make sense

i will just work out the whole system with monitor to get an estimate

2 hours ago, Dennis said:

ok so far thanks to everyone

so if im correwct here

it seems that the 1070 uses 33 cents an hour for gaming

and using the 3080 would use 77 cents an hour

 

this would make sense

i will just work out the whole system with monitor to get an estimate

https://www.takealot.com/digital-watt-meter-kill-a-watt/PLID45208767

 

buy that plug your pc into that and you can see what everything uses

ok thank you very much

Measure it with a meter.

Reminded me when I asked my brother in law why he is now switching off his computer but when he was living with us it was on constantly.

It is difficult to spend your own money. 😂