PoW difficulty increase coming in Nano v21

Nano team has announced that it will be increasing Proof of Work (PoW) difficulty in upcoming v21 release, also known as Athena release. Difficulty will be increased for both send and change blocks by eight times and reduction for receive blocks by 1/8th of current levels.

This is being done to prevent Quality of Service attack. Nano team has been working to increase PoW difficulty in short term due to higher risks.

Their team has done some benchmarking of work generation across various GPUs to find out amount of difficulty to be increased in this release. They conducted benchmarks with Nvidia GeForce GTX 1070, GTX 1080Ti, AMD Radeon Vega 64 and plethora of processors.

Current difficulty estimates
Common consumer GPUs: 3–5 work/s ≈ 0.2–0.4 s/work
Common consumer CPUs: 0.1–1 work/s ≈ 1–10 s/work

Nano V21 Athena –

Send and change blocks
Common consumer GPUs: 0.4–0.6 work/s ≈ 2–3 s/work
Common consumer CPUs: 0.01–0.1 work/s ≈ 8–80 s/work

Receive blocks
Common consumer GPUs: 24–40 work/s ≈ 0.03–0.05 s/work
Common consumer CPUs: 0.8–8 work/s ≈ 0.1–1 s/work

Clearly, you can see there is 4x more difficulty vs send/receive block compared to current standards. These will definitely impact network participants as well.