Scratchpad: 2MB

REMEMBER. YOU USE THIS MODIFICATION AT YOUR OWN RISK!!

See this comment for more information: https://www.xmrstak.com/2018/03/22/polaris-21-based-sapphire-radeon-rx-550-4gb-with-micron-memory-480-h-s/#comment-122

Warning. This article is about Sapphire Radeon RX 550 4GB with Micron memory and Polaris 21 based GPU only!

First, you need my modded bios https://nofile.io/f/85KSqW92ezE/zoolekmod_Sapphire_RX550_4GBMicron_from_RX560_Polaris21_elpida.zip

so download it, and flash your RX 550 with atiflash277 (https://www.techpowerup.com/download/ati-atiflash/). After reboot, patch your driver using atikmdag-patcher (https://www.monitortests.com/forum/Thread-AMD-ATI-Pixel-Clock-Patcher).

This is the standard procedure. So, after reboot give Windows some time to install driver.

Run OverdriveNTool and set Memory P2 frequency to 1850 MHz and GPU P7 voltage to 1000 mV.

then run xmr-stak with config

"gpu_threads_conf" : [ { "index" : 0, "intensity" : 420, "worksize" : 8, "affine_to_cpu" : false, "strided_index" : true }, { "index" : 0, "intensity" : 420, "worksize" : 8, "affine_to_cpu" : false, "strided_index" : true },

If you wan’t have better power draw, but less hashrate, you should undervolt your GPU, for example (I have done all-night tests and it works very well and very stable):

Please notice, the HWiNFO64 reporting some wrong informations with this bios, for example fan speed. Don’t worry about it.

Happy minning with this new Sapphire card 🙂

Did I forget something?

My mail: mariusz.zoolek(at)gmail.com