In what is a depressingly-rare show of pre-release transparency, AMD has posted a support article concerning UEFI support on its RDNA 4-based GPUs, including the soon-to-be-released Radeon RX 9070 series. The article is surprisingly wordy for such a simple topic: AMD will only officially support UEFI systems with graphics cards sporting GPUs based on the RDNA 4 architecture.
Is this the first major controversy for AMD’s new Radeon series? Well, no. In fact, you’re probably not even going to notice. The vast, overwhelming majority of all PCs have been UEFI systems for over a decade now; the machine you’re reading this on right now probably booted from UEFI (unless it’s a smartphone or iDevice.) There’s no real cause for concern unless the PC into which you plan to install your shiny new Radeon GPU dates back to Intel 2nd-generation Core or earlier.
Except there may not really even be cause for concern in that case. You see, while AMD says that “only UEFI mode will be officially supported” on its next-generation GPUs, there’s nothing stopping a board vendor from patching in legacy BIOS support. Indeed, graphics cards based on AMD’s GPUs have been picky about BIOS vs. UEFI for some time, with reports dating all the way back to Polaris (the Radeon RX 480) complaining of a lack of BIOS support. Some cards would boot in old machines and others wouldn’t; supposedly, Powercolor were particularly reliable in this regard, while enthusiasts have claimed that Sapphire boards really wanted a UEFI system.
While AMD shies away from going as far as to say that Radeon RX 9000 series GPUs won’t boot at all in BIOS-only systems (or machines with Legacy CSM enabled), it does write at length about the benefits of running in UEFI mode. According to AMD, UEFI mode offers “greatly improved” system security as well as support for high-capacity disks over 2TB, NVMe SSD booting, Secure Boot, and so on. Surprisingly, the chipmaker barely mentions what is arguably the most relevant UEFI-required feature: Resizable BAR, also known as SmartAccess Memory, a feature which allows the GPU to use a wider aperture to access system RAM, improving throughput there.
Ultimately all you really need to know is that if your system is ancient, or using Legacy CSM mode, you’re going to want to swap over to UEFI mode before installing an RDNA 4 graphics card. Any machine worth using in 2025 should have this support, and it’s possible (albeit clunky) to convert an OS install from MBR to GPT, so you don’t even have to lose any data or settings. Microsoft has a guide exactly for that over here.