Monero RandomX - It's time to clean a dust from your CPUs!

Monero will switch to the new POW, CPU-centric RandomX (november 30 2019), presumably avoiding ASICs for a long period of time.To be sufficiently prepared, a user, service, merchant, pool operator, or exchange should run CLI v0.15 or GUI v0.15.

Major changes

- new algorithm - RandomX
- long payment IDs will be phased out 
- transactions will now require at least two outputs
- ten block (approximately twenty minutes) lock time.

Are CPUs back in the game?

YES. RandomX is designed to be CPU-centric. CPUs are the most distributed computing resource in the world, according to Howard Chu (RandomX developer), who stated:
"Practically everyone in the world now has a smartphone in their pocket with a CPU and memory that’s capable of mining RandomX".
The goal is to decentralize mining as much as possible, which is why the Proof of Work RandomX will favour CPUs over ASICs for at least the next three to five years, according to Chu.

What about GPUs?

With the activation of RandomX, Chu expects CPUs to be at least three times more powerful than GPUs when mining Monero.

Some benchamrks

CPU:
AMD 3900X: 13330h/s(RandomX) | 1335h/s(Cn R)
RYZEN 3700X: 6853h/s(RandomX) | 1018h/s(Cn R)
RYZEN 5 3600: 6580h/s(RandomX) | 803h/s(Cn R)
INTEL I9 9900K: 2102h/s(RandomX) | 630h/s(Cn R)
INTEL I7 7700K: 2100h/s(RandomX) | 350h/s(Cn R)

GPU:
- Vega 64: 1225h/s(RandomX) | 2200h/s(Cn R)
- RX 480/580: 400-410h/s(RandomX) | 960-1000h/s(Cn R)
- RTX 2080 Ti (1915/13600 MHz): 400-410h/s(RandomX) | 960-1000h/s(Cn R)

RandomX Modes

RandomX has two modes with different memory requirements and performance. Fast Mode requires 2GB of shared memory but has 4x-6x the performance of Light Mode which only requires 256MB of RAM. Fast mode is intended for dedicated miners. Light mode is designed to allow fullnodes to validate blocks without requiring the 2+GB of RAM, so that small devices (like ARM single-board computers, e.g. Rock64) can still be used as standalone nodes.

Monero has always shown a certain resentment towards specialised mining hardware since the very beginning. Allways with the aim of making changes to the Proof of Work based on CryptoNight to exclude ASICs and FPGAs from the mining of Monero.

From the genesis block, the currency has undergone three forks

- Cryptonight V7 06. Apr 2018
- Cryptonight V8 19. Oct 2018
- Cryptonight R 10. Mar 2019
- ... RandomX 30. Nov 2019

Sources:
getmonero.org
cryptonomist.ch
medium.com/luxor
cryptunit.com
monerobenchmarks.info
github.com/SChernykh/RandomX_OpenCL
github.com/SChernykh/RandomX_CUDA