Here's a more complete guide/information that I've gathered:
If you have a power limited 3090 FTW3 card like I do (power perfcap shown even at 390W in the Valley benchmark), the XC3 Ultra VBIOS (which I sometimes just refer to as XC3 or XC3 VBIOS) will open up your card. It bugs out the power readings (AB, GPU-Z, etc.), so total power draw isn't accurate - use a kilowatt meter or UPS reading to see the before/after results. You should use Afterburner (which I usually refer to as AB) instead of Precision X1 (which I refer to as PX1) since using the XC3 VBIOS will have PX1 wanting to flash the XC3 firmware to your FTW3 Microcontroller Unit (MCU - the fan controller / RGB controller) - which will likely cause fan / RGB control issues.
This VBIOS WILL result in your card producing more heat because your card will be drawing more watts - on air my card got up to 78C at 100% fan speed, but with the hybrid kit it maxed out at 64C.
The fans will likely act a bit buggy too - when at 100% fan speed they'll wind down and then ramp back up under load. I got around this by offloading my hybrid kit's radiator fans onto a fan controller.
Why do this? Well, my card would usually game at 1920 to 1950Mhz with any VBIOS other than the XC3, and benchmarking would see a max average of 1996Mhz in Port Royal (on a good run). With the XC3 VBIOS, my card's GPU stays at 2100MHz while gaming, and benchmarking can see 2160+MHz in Port Royal. Quite the difference!
Of note - this is not an unlocked VBIOS, so it
should not void any warranties like the kingpin 1000W "unlocked" VBIOS and because it is a dual VBIOS card. It just changes something on the card so that it doesn't downclock / undervolt itself to near stock levels of performance even with a hefty +200 GPU offset, like my card does. Likely something to do with the fixed voltage level analog controller that EVGA decided to use, and so it lowers my 77W PCIE slot power draw to the 66W (or lower) and likely the same for my VRAM (which is another reason the card will perfcap power).
Also of note, the reason for using the XC3 VBIOS instead of some other 2 power pin VBIOS is because the display outputs (HDMI, DP) are the same between the XC3 and FTW3 - and thus will all work.
Tools that you will need:
NVFlash (download the October 1st version, otherwise you won't have the nvflash64 executable - you might be able to use nvflash instead, and use "nvflash" instead of "nvflash64" as a command - I've not tested it)
XC3 Ultra VBIOSMSI Afterburner 1. Reset/remove any GPU/VRAM overclocks in AB (you shouldn't use PX1 for the reason stated in the first paragraph). Close AB completely (right click on the tray icon and choose Close).
2. Open command prompt in administrator mode. Windows key, type CMD, right click on Command Prompt, select Run as Administrator, choose Yes.
3. Navigate to where you unzipped NVflash and put the unzipped XC3 VBIOS. Open the folder and highlight the path bar and copy it (something like C:\Users\USERNAME\Desktop\nvflash ). Type, without quotes, "CD" a space (for Change Directory), then right click in the command prompt to paste the NVFlash folder. Press the Enter key to change the directory.
4. Backup your current VBIOS for later. Use the following command, without quotes, in command prompt to do so: "nvflash64 -b name.rom" (name can be whatever you want it to be WITHOUT spaces). Don't be alarmed when the screen blanks - that's just the driver being deactivated / reactivated in order for the tool to download the VBIOS.
5. Flash the XC3 Ultra VBIOS. Using the same command prompt window, and still without the quotation marks, type the following command: "nvflash64 -6 EVGA.RTX3090.24576.200902.rom" and press Enter.
6. When prompted, press "y" which will be asked twice.
7. When the process finishes (after some more screen blanking) reboot the PC when prompted to do so.
8. After windows loads again, it will reinstall the graphics driver. I highly recommend one more reboot.
9. Use AB and your benchmark / game of choice to find your new max overclock offsets. VRAM likely won't change, but your GPU offset likely will - and your card will likely be at a higher GPU clock speed than it ever was before even with a hefty overclock.
To restore your backup VBIOS, simply repeat steps 1 through 5 (skipping 4), and use NAME.rom (whatever you named the file as). Or use any 3090 VBIOS, including the XOC or stock VBIOS, from
Techpowerup's database.