Flashing alternative vBIOS versions onto GPUs is a common practice used by modders to increase power limits on GPUs, and it has only become more common since NVIDIA started clamping down on overclocking options available to users via software tools. The recently announced ASUS ROG Matrix Platinum has become an attractive source for one such high-wattage vBIOS, although it has proven difficult to get the aforementioned vBIOS onto certain cards. One user on the HardwareLuxx forum, however, has managed to get the 800 W vBIOS from the Matrix Platinum GPU onto an ASUS ROG Astral GeForce RTX 5090 (read our review of the latter here), although the mod only seems to be necessary on the black version of the card.
It turns out that in order to flash the Matrix vBIOS onto the black Astral 5090 required physical modifications to the GPU PCB itself—this is due to the rear-mounted fan being wired with the front middle fan on that particular version of the card, as opposed to on a separate header as it is on the white version. The modification in question involves swapping a pull-down resistor in the serial in signal line of the EEPROM to a pull-up resistor. Obviously, this mod alone requires more than a little bit of soldering experience, but there’s also the question of cooling. The stock version of the ROG Astral is designed with a 600 W power limit, and the Matrix vBIOS lifts that to 800 W, so realistically, any overclocking attempts made with the modded card requires an aftermarket cooling solution to handle the increased power and corresponding heat.