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The AMD Radeon RX 550 on the way to 500H/s on CryptoNight V8

The AMD RX 550 is absolutely the best ROI (Return on investment) card on the planet. You can buy one for only around 100$ (or 100€) and push it above 500H/s mining with the CryptoNight algorithm. Out of the box at stock settings, this card gets only about 250H/s on a single thread, but with some simple tweakings, you can boost its performance. But, what about the new CryptoNight V8 algo?

The Radeon AMD RX 550 Polaris GPU
The Radeon AMD RX 550 Polaris GPU

AMD Radeon RX 550. An absolute bargain for the mining beginners

AMD’s affordable Radeon RX 550 is designed for folks who want to not spend a lot of money to buy a video card for mining. It’s ideal to mine CryptoNight, rather than Ethash or other algorithms.

For less money, you can buy also a good performance in mining. It’s clear a bargain.

The Radeon RX 550’s Polaris GPU packs 8 compute units and 512 stream processors, along with at a 1,100MHz base/1,200MHz boost clock, married to 2GB/4GB of GDDR5 memory with a 128-bit bus. The Radeon RX 550 is powered completely via your motherboard’s PCIe slot, with no extra power cables required. That’s a big deal for mining because 40W at the wall for one card is really really little electricity to pay and electricity in mining is half part of the equation. The AMD RX 550 is absolutely one of the best cards for ROI (Return on investment): pay less, do more.

We need to make a BIOS modification to push high the RX 550, so a big WARNING: if you’re new to mining, or aren’t really too techie, pay attention because you can basically brick your GPU if you do it incorrectly.

How to overclock and undervolt your Radeon RX 550 card

Let’s start. First you need a Linux or Windows 10 operating system with installed the Radeon Blockchain driver, this is the official driver specifically for blockchain computing released by AMD and you can find it at

Some cards have issues with the Radeon Blockchain driver and also the driver is still a BETA driver, so you can install one of the latest versions of the AMD Adrenaline Radeon driver. It is not specific for blockchain computing, but you can easily enable the compute mode. You can find the Adrenaline at

Pay attention to use 18.5.1, 18.6.1 or 18.9.3 versions on Windows and a version prior to 18.40 on Linux. Also, don’t forget to enable compute mode!

How to Switch Between Graphics and Compute GPU Workloads Within AMD Radeon™ Settings

Or using this dword in Windows registry:

Windows Registry Editor Version 5.00


Also, you need the AMD/ATI ATIFlash utility. This is the program to flash and back-up the BIOS of the card. For Windows 10 at and for Linux at

Then, to make the modification of BIOS you need the Polaris Bios Editor. I suggest you the Jack Edition because it has a simple ‘one button click’ to make the time strips mod optimal for your card. You can also modify the clock settings of the GPU and the memory of the card. You can find it both for Win or Linux at

On Windows 10, you also need the AMD/ATI Pixel Clock Patcher. This is because your PC could not recognize the graphics card after the reboot. So, get it at

I suggest you also to get one of the following programs, they are for editing some parameters (especially frequencies and voltages) in the modern AMD cards. So with these, you’ll be to tweak a bit more your cards. Get OverdriveNTool for Windows at or AMDCOVC for Linux at

How to configure the miner program to get the best hashrate on the CryptoNight V8 algo

Finally, the miner. I always used XMR-Stak and I like it, but you can find really a lot of programs that do the same thing. It is both for Windows 10 and Linux, you can find binaries and sources at The latest 2.7.1 release provides an auto-config mode that adjusts settings to the best value for your card. Config files from 2.5.X+ are compatible and 2.4.X or older are NOT compatible with this release. If you remove the old amd.txt file you will get a new version with new tuning parameter.

Start with a back-up of your card’s BIOS and then mod it with Polaris Bios Editor. Use the ‘One Click Timing Patch’ function to patch the BIOS’ timings and set the GPU Clock to 1450 MHz and the Memory Clock to 1900 MHz. Save your modded BIOS with another file name and then push it to the card with the AMD/ATI ATIFlash utility. Run the AMD/ATI Pixel Clock Patcher if you’re on Windows, so you’re sure that the system will detect your GPU. Reboot your system both on Windows and Linux.

At reboot, run XMR-Stak for the first time. You will be prompted to answer really few questions and for the question about the currency you’re mining, select the one you like or just put in “monero”. – UPDATE: after the network upgrade, you should put ‘monero’ or ‘cryptonight_v8’ for mining Monero or you’ll mine for nothing – For the rest of the answers, you must type your wallet address and the pool chosen for mining.

By pressing ‘H’ with XMR-Stak running, you can check your actual hash rate value, the speed of your mining. Now shut down XMR-Stak by pressing ‘CTRL+C’ and go inside the folder where XMR-Stak program is. You’ll see many files and you must edit the amd.txt one. Open it with a text editor and make a modification of it like the following one under the “gpu_threads_conf” section.

"gpu_threads_conf" : [
  { "index" : 0,
    "intensity" : 448, "worksize" : 16,
    "affine_to_cpu" : false, "strided_index" : 2, "mem_chunk" : 2,
    "unroll" : 4, "comp_mode" : true, "interleave" : 40
  { "index" : 0,
    "intensity" : 448, "worksize" : 16,
    "affine_to_cpu" : false, "strided_index" : 2, "mem_chunk" : 2,
    "unroll" : 4, "comp_mode" : true, "interleave" : 40

Save the amd.txt file you just edited and re-run the XMR-Stak application. Check the new hash rate by pressing ‘H’ and you will see that you get around 480-490H/s.

Isn’t it better now?

UPDATE: many people suggest me to use CastXMR (and version 1.2.0 seems to support the AMD Radeon RX 550) to get the better hash rate on CryptoNight V8. I remain with the XMR-Stak program, but if you want to try this is the link:

***WARNING!!! Pay attention to go high with frequency because you can burn your cards!!! Make a step-by-step trial period to test where your cards can go because every card is different, every memory is different and maybe you lose the silicon lottery!!!***

Overclock steps and NiceHash bonus tips

After that, if you want to push your AMD Radeon RX 550 to the max, you need to use an overdrive tool to overclock frequencies and to undervolt voltages. So, start with the programs suggested above and make your trials. Remember that any card is different, any memory is different, you can win the memory lottery or not, you just need to try a different combination of frequencies and voltages to find the best one that fits your card. You can find all the info on how to use OverdriveNTool and AMDCOVC on the relative websites.

Issue on NiceHash: getting rejected shares on CryptoNight V8 or CryptoNightHeavy?

All the info at this address:

Using 3rd party miners (like xmr-stak, cc-miner, xmr and cast-xmr), you might get rejected shares on CryptoNight V8 algorithm due to wrongly set parameters. The most common reason for rejected shares is not choosing the correct algorithm for mining the desired coin. Make sure you select the correct algorithm for the coin you want to mine! Also check the pool compatibility with the desired algorithm. 

For CryptoNightV8 please make sure you are using the following settings (xmr-stak; LOCATION: eu, usa, hk, jp, in, br):

“pool_list”: [
           “pool_address”: “”,
           “wallet_address”: “BitcoinWalletAddress.WorkerName”,
           “rig_id”: “”,
           “pool_password”: “x”,
           “use_nicehash”: true,
           “use_tls”: false,
           “tls_fingerprint”: “”,
           “pool_weight”: 1
   “currency”: “cryptonight_v8"