Basic overview to use an Elmor EVC on Navi31
(Beware: this is a hardware modification, providing low level control; bypassing factory safeties. Every part of this could easily destroy your hardware, instantly or eventually)
Hardware: you will need to connect the PMBus to the EVC via soldering either wires or a pin header to three pads on the back of the card and connect to one of the I2C headers on the EVC (see image below)
View attachment 2605202
Software: Be sure you have the latest elmorlabs EVC software (at least
1.0.1.15 (which requires 0009 firmware))
1: Select the relevant I2C bus in left pane
2: Click 'Find devices' (typically this would auto-detect and populate any devices found, but for now, this is not functioning with these controllers; so currently you will have to manually set-up using the addresses found)
2a: To manually add, simply select the appropriate profile for the voltage controller and its associated address, then click 'Add', this will add the device to the left pane under the current I2C bus (see list below)
7900XT(X) uses:
-MP2857 on address 22 (Core)
-MP2856 on address 26 (Memory)
-UNCONFIRMED: I believe address 24 is also the MP2857 for SOC
[2856 and 2857 use the same parameters, so you can use 2857 for both until new version of software available]
-Any other addresses found are not useful here
*If your card uses different addresses, you will have to trial (wait for software update so you can verify association via reported voltages)
3: You can now click on the relevant controller/address in left pane to modify parameters (Monitoring on the 1.0.1.15 release is not correct)
Note: Controllers may have multiple outputs (eg. MP2856 on address 26; Loop1 is for the memory and loop2 is for the memory controller)
4: You can change parameters by selecting from the drop boxes and hitting 'Apply changes' (note these are not permanent and will reset if the card loses power: eg. cold boot)
The only relevant settings for 99% of us are:
-VID offset (simply a fixed offset of voltage output)
-Iout Gain (this functions as a current (amps) reporting offset, and thus is used to make the chip report it is pulling more/less power than it is; e.g. lower this value to increase power limit)
Please lower the Iout gain in gradual steps, these cards are capable of pulling tremendous power (I pulled ~800W at stock voltage)
Also since this affects the power reporting, power and current reading in software are invalid, I suggest having some way of monitoring estimate power draw (eg. Kill-a-Watt at the wall, or current clamps at the PCI power cables)