AMD's Radeon RX 6600 XT just launched earlier today and has already found its place on the list of best graphics cards. While the Navi 23-powered graphics card is a solid performer, it's also quite efficient at Ethereum mining.
Clock speeds for the Radeon RX 6600 XT vary from one model to the other, depending on the manufacturer. However, the graphics cards should perform more or less in the same alley before optimization. Out of the box, our ASRock RX 6600 XT Phantom Gaming OC pumped out 28 MH/s in Ethash. With a bit of tuning and overclocking the GDDR6 memory, we got the hash rate up to 32 MH/s.
If we just concentrate solely on the hash rate, the Radeon RX 6600 XT doesn't look very impressive at all, considering we can squeeze out similar mining performance on a Radeon RX 570 or RX 580 with some finetuning. However, the Polaris-based graphics card do draw more power, and that's the area where the Radeon RX 6600 XT really excels. While the Radeon RX 570 or RX 580 can pull over 130W, the Radeon RX 6600 XT kept its power consumption within the 75W margin.
The ASRock RX 6600 XT Phantom Gaming OC was averaging between 74W and 75W as you can see from our Powenetics equipment, which gives real-time power data. Software-based tools, such as HWiNFO64 or MSI Afterburner typically underreport power consumption. The first exhibited at least 12W to 14W lower values, while the latter's measurements varied by around 15W.
At 32 MH/s, the Radeon RX 6600 XT would sport a performance per watt rating of 0.43. If you look at out list of best mining GPUs, you'll find that the Radeon RX 6600 XT is a lot more efficient than other RDNA models, such as the Radeon RX 6800 or the GeForce RTX 3060 prior to Nvidia nerfing the Ethereum mining performance of its GeForce RTX 30-series (Ampere) lineup.
The Radeon RX 6600 XT, like any other graphics card launched during the pandemic and global semiconductor shortage, suffers from scalping and limited stock. The Navi 23 graphics card was out of stock at major online retailers, including Newegg and Amazon. Micro Center, on the other hand, had around 2,000 units spread across 25 different locations around the country. Let alone gamers, even miners might find it hard to get their hands on the Radeon RX 6600 XT.