AMD Navi 12 BC-160 Mining Cards on Sale in China

[harlan4096]

Mining farms are already running these chips

Another AMD partner is shipping mining cards based on the company's silicon, this time via Aliexpress. From the listing we seem to have an XFX graphics card designed for mining workloads. The new XFX BC-160 card makes use of Navi 12, manufactured on 7nm silicon and packing 2304 Stream Processors across 36 Compute Units. It employs 8GB of HBM2 memory running over a 2048-bit bus.

XFX's BC-160 features a straightforward naming scheme that's unlike any other AMD product. According to spec sheets and marketing materials for the cards, decoding the product code results in a Blockchain Compute (BC) card, in the first generation (1), offering up to 69.5 MH/s typical ETH mining performance (BC-160) in a 150W TGP envelope. This hash rate was achieved under the RedHat release of Linux, which we assume refers to RHEL (Red Hat Enterprise Linux) as Red Hat Linux was discontinued in 2004. The cards also claim compatibility with the Ubuntu distro.

There are a lot of interesting elements to this card. For one, the Navi 12 silicon was primarily used in one other AMD graphics product: the Radeon Pro 5600M for laptops, specifically Apple's MacBook Pro 16-inch model. It was also used in the Radeon Pro V520, though likely in far lower quantities, and that seems to be the basis for the BC-160 design. It's interesting that there are now apparently enough surplus chips that AMD is allowing partners to repurpose the GPUs for mining cards. Then again, with Apple shifting it's MacBook Pro line to its own M1 Pro and M1 Max, there's a good chance it has no real desire for additional AMD GPUs from 2020.

Another interesting point is that these XFX mining cards are powered by two 8-pin PEG connectors. Considering a single 8-pin connector can supply 150W of power, and the PCIe x16 slot can deliver another 75W, putting two connectors on the cards seems overkill. Again, these were chips originally used in laptops, where they were tuned to consume far less than 150W — 50W, to be precise. The AMD Radeon Pro V520 had a 225W TGP, though, and similar to the BC-160 it used a single blower-fan cooling design, which should be adequate for cooling the cards considering the workloads they're meant to handle. Ethereum mining strains VRAM more than anything, and the screenshots indicate power use of around 120W.

The use of HBM2 is part of the Navi 12 design, but at least on the MacBook Pro models it was clocked at a relatively low 1540 MT/s. Even with a 2048-bit bus, that's just 394 GBps of bandwidth, while the desktop 5700 XT GDDR6 models had a 256-bit interface and ran at 14 Gbps for 448 GBps of bandwidth. The screenshots show the BC-160 mining at "1275," which looks slower than the MacBook Pro model, but it's likely double that speed in MT/s, meaning 652.8 GBps of bandwidth after overclocking.

That would explain how the card manages 70 MH/s in Ethereum mining, where the RX 5700 XT after tuning tops out at around 55 MH/s. At stock, the HBM2 likely runs at the same 2000 MT/s as the AMD Radeon Pro V520, which would put the hashrate at the target 60 MH/s. On other words, the BC-160 delivers more bandwidth than the otherwise similar Navi 10 GPUs that used GDDR6.

Being a mining card, these are headless designs, so there's no display output. That means these cards are unfortunately only ever going to fulfil a singular purpose and will never be among the best graphics cards for gaming. They're pretty much solely designed for miners, potentially keeping said miners away from the gaming-oriented RX 6000 series. That's too bad, and it shows once more than the graphics card companies are more than happy to prioritize mining cards if that's where they can make the most money on sales.
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