Kind Ladies/Gents, I’ve done quite a bit of reading amongst many outlets over the past several days. (Even re-reading concepts that I feel I have a pretty firm grasp on, just to make sure I’m not missing something.)
Even so, I can’t seem to figure out if the voltages/wattages/amperages I’m seeing is correct, or if I’m missing a piece of important information in my calculations. So I believe I need a little assistance figuring it out.
Relevant Components:
13900k
MSI Z690 Tomahawk
DDR4 @ 1.5v
RTX 4090 (600w Power limit)
Pertinent BIOS settings:
CPU Wattage limit: 315W
CPU Amperage limit: 450A (Explaination below)
CPU Temp limit: 100C
CPU vCore: Auto
All load line calibration settings: Auto
These settings are my attempt to keep the total system power under 1000w (910w /1500va UPS in use, but with slightly higher amp batteries, so a 110% UPS load doesn’t really concern me too much.)
The “auto” voltage was set as such because it was my impression that any voltage under 1.72v, while staying at, or below 245A and 100c is “safe” … ish?
So I don’t really care what the voltage is, so long as the CPU stays under 100c, under 315 watts, and under 245 amps.
Under AIDA64/Cinebench R23/etc (eg. Pretty much any load that will push the CPU to the wattage/temp limit) HWINFO64 reports:
Max wattage: 313w (+/- a few milliwatts)
Max voltage: 1.506v
Min voltage: 1.294v
Max Temp: 101c
Which means, by my math, amperage equals:
At worst (1.294v): 241.89A
At best (1.506v): 207.84A
However, if setting the amperage limit to 245A in BIOS:
Max Wattage: 126w
Max voltage: 1.456v
Min voltage: 1.077v
Max Temp: 60c
Which (again, if my math is correct, and I’m not missing anything) would mean the amperages roughly equal:
At worst (1.077v): 116.99A
At best (1.456v): 86.54A
This is where I’m stumped. Unless I’m missing a critical piece of math (a voltage/amp droop that must be compensated for?) how is it possible to end up with these numbers when setting an amperage limit of 245A? Could these readings be completely incorrect/unreliable?
Any help is greatly appreciated!
At 450A setting:
At 245A setting:
