Power analysis of 12v pci-e vs reading.
I took some readings with my DC clamp on ammeter on the +12v (yellow) wires that go to the 8 pin pci-e connector on my XFX RX 480 RS.
Both the 480 and 580 powercolor red dragon bioses read the same current in 3dmark firestrike same fps results, despite my 480 bios saying 140-150w and the powercolor saying 170w. In the same test using the sapphire and MSI roms, it was saying more. Odd right, different settings for sensors.
So what is the real wattage, I wanted to know. I took current readings at different wattages to guess what is real. Of course I can't read the power coming from the pcie slot, but that is usually at most 5 amperes or 60 watts (5a x 12v=60w).
Readings of powercolor rx580 bios at PCI-e power connector- not including pcie slot power
Amps/ Watts on hwinfo/ calculated watts using 12v / watts on pci slot (?)
6.2a/ 90w/ 74.4w / 15.6
7a/ 110w/ 84 / 26
8.2a / 124w/ 98.5 / 25.5
9.0a/ 138w/ 108 / 30
10a/ 159w/ 120 / 29
10.5a/ 165w/ 126 / 39
11a/ 173w / 132 / 41
So pretty much it seems accurate at higher levels, 1 amp is 12 watts and it goes up that way all the way. Scaling is correct. But we don't take into account The pcie slot power use which can be up to 5 amps/60 watts.
That is around 20-40 watts it seems. I would guess that some cards use less or more, depending on phases. Maybe that is why the MSI bios reads way too high, it's calculating using different estimations? Who knows.