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6900XT Power Limit Tricks

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Good to hear. Thanks!

@splave Have you found a fix to the glitch you mentioned (PC rebooting when too much voltage offset is applied)? The minimal power used is great, but I find that this glitch limits my card’s overclocking potential.

For example, in Fire Strike Ultra, any voltage offset of more than 88mv on the EVC2 leads to a reboot (It’s even lower on Time Spy Extreme). My highest score is still with high clocks and voltages cranked up in conjunction with MPT (15,200+ in Fire Strike Ultra). Using splave’s smart trick, I can only manage 15,029 points. Maybe this trick is not really apt for instances when you’re trying to squeeze in as many points as possible? Thank you.

EDIT: I have a 6800 XT. The EVC2 settings apply to this card as well, right?

ElmorLabs EVC2SX i was bought  last year. Now can it support mp2891 ic through firmware update?

Quote from 24146872 on 2022-05-06, 22:55

ElmorLabs EVC2SX i was bought  last year. Now can it support mp2891 ic through firmware update?

As of recently it can through a software update:!Atmpv-6qHr_63JgdlCr0gwxJQ7cHuQ?e=sG6HO1

Thank you for sharing this, I actually have an RX6900Xt that I'm trying to bring to life again, I started with 0 rails present on the card except the 12v, 3v3 and 5v.. 
Now I have all rails up and running except the ones from the IR35217 (MVDDC and VDDCI) which was actually shorted dead and I had to replace from another dead pcb card, I have managed to get into the i2c via an esp32 controller, and was able to see these addresses, I was lost on which device is which until i saw your picture 🙂 Now I know what i see is correct at least.. 
The ir35217 is definitely not configured for 1+1 loop configuration,  is that bit settable? can i change the loop configuration of the device by writing something to somewhere, I could not find anything in the datasheets for that configuration, so I wonder where does it get populated from?
Thanks everyone once again
Quote from splave on 2020-12-31, 10:35

Jon was nice enough to send me some test builds of the XDPE132G50 IC that controls the vrm on the 6900XT. Trying each value one by one we found we were able to greatly reduce the power sense output similar to what a shunt mod does on Nvidia. Since there are no shunts....this is the way. 

Start by flashing up your firmware, I am using 8e.

Latest firmware:

Next grab the software with the new profile for our 6900XT PWM.



Now you want to slap on your SDA/SCL/GND (pics courtesy of Elmor) you can use either spot, I used the IOR controller spot so I could just grab the screw mount for sure ground.


After that, I suggest reinstalling some fresh drivers especially if you have been playing with MPT at all. Everything went much smoother that way. Next just to verify everything is working I suggest you run a stock clock run of whatever gpu bench you like with GPUZ logging max GPU wattage / temp / and clock. Here is my before and after. 


Settings for XDPE


Settings for IR35217


With more breathing room the card was able to run 2700-2800 set in AMD overdrive on water cooling for Fire Strike Ultra. The efficiency is really great when the wattage use is low like this. 


Some snags I ran into: some sort of protection when using in my case too much voltage (1.10) the computer would shut down under load lowering it let me pass (1.05). You will run into a point also where adding more vGPU is letting you increase your clocks that you set but the score will be worse or not change. Running at the bleeding edge you should also take note that the driver sometimes needs to be refreshed if you keep failing a specific test for no reason. I tried adding MPT into the mix to push even further but changing any setting at all really made my score drop. Maybe others will have more success there.


If anyone gives it a shot let me know how it works out and if you have anything to add. Cheers and happy new year!



Uploaded files:
  • getting-into-rx6900xt.png

Well, I think I tried to make the changes as per your image, the 0x14 0x27 register is not accepting is accepting the 0x0e 0x2D Command to set the phases to 1+1 on i2c address 0x0a after going into test_mode.. but the settings dont persist, even after trying the store_all_command, I think I may need to buy a new chip..hopefully not programmed yet.. I think I need to investigate a little bit more

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