Modders unlock 256-bit bus on AMD’s first gen RDNA GPU

Brazilian modders at it again.

The AMD Radeon RX 5600 XT made its debut in January 2020 as part of the mid-range Navi 10 XLE lineup. Featuring 2304 Stream Processors, it initially came with a memory downgrade to 6 GB and a 192-bit bus. In comparison, the RX 5700 XT boasted 8GB of memory and a full 256-bit bus. Notably, the workstation model called Radeon PRO 5700 XT even supported 16GB.

This context sets the stage for the impressive results of Paulo Gomes’ team , who successfully upgraded the memory and unlocked the full memory bus on the GPU. Such modifications are rare due to their complexity and the challenge of locating the necessary bits in the BIOS to enable such support. Gomes’ team managed to accomplish this feat by adding a hexadecimal input instruction to the firmware that activates the disabled memory controllers, effectively ‘uploading’ additional memory.

The team executed three mods. The first involved enabling the new 256-bit memory bus, which proved to be a challenging task. Initially, benchmark results indicated performance that was nearly half of the stock 6GB configuration. However, this issue was swiftly resolved by utilizing a different BIOS from Gigabyte. As a result, performance saw an 11% increase.

PowerColor RX 5600XT memory reballing, Source:Paulo Gomes

Unigine SuperPosition 1080p Extreme Test

• RX 5600 XT 6GB/192-bit (Stock): 3944
• RX 5600 XT 12GB/192-bit: 3953 (+0%)
• RX 5600 XT 12GB/192-bit (OC): 4514 (+14%)
• RX 5600 XT 8GB/256-bit: 4380 (+11%)
• RX 5600 XT 16GB/256-bit: 4387 (+11%)
• RX 5600 XT 16GB/256-bit (OC): 4979 (+26%)
• RX 5600 XT 16GB/256-bit (OC Ronaldo Buassali mod): 5115 (+29%)

The whole process also involved 12GB/192-bit and 16GB/256-bit configs, but the capacity increase did not provide any performance benefits for actual testing. The 11% increase comes mainly from increased memory bandwidth of 33%. With some further tweaking (overclocking) the team managed to score 5115 points in the same test, which accounts for a 29% increase over stock GPU specs. That’s nearly the same performance as the next-gen RX 6600 XT.

RX 5600XT overclocked and modded, Source:Paulo Gomes

AMD has not previously introduced a GPU like this to the market. Maybe some users will now consider sending their old GPU to Brazilian modders to unlock hidden performance. However, increasing the capacity could come at a significant cost, almost equivalent to the price of the GPU itself, with the 5600XT selling for $109.

Kudos to the skilled modders, and it’s hoped that they’ll explore recent GPU releases like the RX 7700 XT, which similarly features a locked memory bus at 192 bits.

Source: Paulo Gomes (Testing and Optimizations) , (The mod)