All About BTC, LTC, ETH mining as well as other alternative crypto currencies
If you have checked our publication Testing the AMD Radeon RX 480 for Ethereum Mining you should already know that at the moment you are a bit limited in your capabilities of reducing the power usage of the new RX 480 GPUs. The pretty much only way to lower the power usage for mining Ethereum with Radeon RX 480 is to use the Power Target reducing it below the 100% value (150W TDP) and thus forcing the GPU to lower its operating voltage and frequency in order to still fit in the allowed TDP. Using a lower operating frequency and voltage for the GPU with the power limiter set at the right value should lower the power consumption, but not change the performance you get while mining Ethereum. Further lowering it below that optimum spot and you will start seeing a drop in mining performance, so our goal here was to find the sweet spot where the hashrate will not be affected.
We have started with the default settings of the RX 480 for both the GPU (1266 MHz) and the VRAM (8000 MHz) and started lowering the Power Target slider until we have reached the 83% – the value at which the power is getting reduced, but the hashrate remains the same. Going below 83% percent of the 150W TDP started lowering the hashrate below the regular value at 100% power. The result was 149 Watt drawn at the wall, taking in consideration the PSU power efficiency that should be about 130W actual power usage. This is down from 177W at the wall with default settings with pretty much the hashrate unaffected and the temperature also went down from 68 to about 60 degrees Celsius.
Repeating the same procedure as above, but with the video memory set at 9000 MHz and the Power Target set a bit higher at 85% we saw a very slight decrease in performance with just about 5W extra power usage at the wall (155W). The performance we got with this setting was about 27.8-27.9 MHS and the operating temperature was down from about 72 degrees to about 63 degrees Celsius, so definitely a good improvement. For the moment the only way to reduce the power usage without a drop in performance is by lowering the TDP limit under the default value of 100% and you can easily reduce the power consumption with something like 30 Watt at the wall (if using 80 Plus Gold PSU). You can experiment by further reducing the power target slider under these recommended values, however with the additional power savings you should also start noticing reduction of the hashrate you are getting. Still if you are looking for optimal efficiency you might try going lower and if you already have Radeon RX 480 and use it for Ethereum mining you are welcome to share your settings in the comments below.