AMD's Polaris 11 GPU has a possible 16 Compute Units composed of 64 shaders each to provide a grand total of 1024 Stream Processors. However, as noted in the HEXUS review of the Sapphire Radeon RX 460 Nitro 4GB, the RX 460 graphics cards have only 14 Compute Units enabled, resulting in 896 Stream Processors available. Just ahead of the weekend der8auer from Overclocking.Guide published a guide detailing how to update your RX 460 BIOS to unlock those extra Stream Processors.
At the time of writing only the Sapphire Nitro 4G and the ASUS STRIX O4G versions of the RX 460 have been tested and have modified BIOS files available. 5x Asus cards and 1x Sapphire cards were tested successfully. If you have one of these models the process is "pretty simple," says der8auer, and outlined in step-to-step fashion on the guide website, as linked above.
First you should backup your current video card BIOS using the function in TechPowerUp's GPU-Z software. Then you download and unpack the appropriate (Asus or Sapphire) unlocked BIOS files from Overclocking.Guide. From the unpacked file payload you run 'flash unlocked bios.bat' and wait the requisite 15 seconds or so. Restart your system once the above step is complete, and enjoy your extra 128 Stream Processors. An approximate 8 per cent performance uplift should be precipitated by the BIOS unlocking. This is backed up by a couple of benchmark tests in 3DMark Firestrike, and The Witcher 3, as below.
Over the weekend I've noted at least two tech websites verify that Overclocking.Guide Stream Processor unlocking via BIOS update works. VideoCardz unlocked another Sapphire NITRO successfully. TPU also was successful in using the BIOS mod but noted a 4W increase in peak power consumption in its more rigorous tests.
AMD Crimson ReLive BIOS verification
Please note that updating the video card BIOS could be risky, and the above description of the process isn't a recommendation to go ahead and modify your RX 460. Also of note is that AMD has locked the new Crimson ReLive drivers to work only with cards possessing verified BIOS signatures. So, if you do this BIOS mod you will have to use the previous Crimson 16.11.5 driver suite.