It used to take nearly 2 months on computers much faster than a Raspberry Pi 4, so yes it's an achievement. It's not insanely complex or anything, but there have been clever technical innovations in the the storage structures (how the database works) and in the network protocols designed to be sympathetic to the storage layout, that have sped it up a lot. Solving these was not easy, though seeing how they work is obvious in retrospect if you understand how storage and networking performance behave generally, which most people don't.

The syncing bottlenecks were mostly storage performance bound, not CPU bound, so the Raspberry Pi thing is not as relevant as it may look to someone who doesn't know the difference.

Ah, right, storage performance bound.

The Etherium blockchain is roughly 1122.97 GB. Cool, how long would it take me to write all that data with an RPI4? Let's pick the ~20th fastest SSD listed, just so we ensure we don't have a ringer in the data: https://pibenchmarks.com/benchmark/53760/

Awesome, let's do some division. Let's pick the DD speed: 1122.97GB/174 MB/s = 1.79273627 hours. Hm, that can't be it.

The RPI4 could write the entire Eth blockchain in under 2 hours. Hmm. Well, maybe there's lots of data being added in a torrent at the end? That could be a real problem?

https://ycharts.com/indicators/ethereum_chain_full_sync_data...

Looks like it's adding about 3GB a day. A rip roaring rate of 34.7222222 kBps.

Ok with the data in hand, this looks like a pathetic system and it doesn't look like a technical achievement. It looks like an embarrassment to me. Could you check my numbers?