One of the most common complaints from new Nerva users is how long it takes to sync the blockchain from scratch. We heard you. We’ve been working on a set of code optimizations (tracked internally as PR65) specifically targeting sync performance, and we now have real benchmark results to share.
On an AMD Ryzen 9 7950X, PR65 synced the entire Nerva blockchain — over 4.2 million blocks — in 19 hours and 49 minutes.
The baseline v0.2.0.0 release was measured at 23 hours 9 minutes to reach block 3.5 million; extrapolating at the observed rate, a full baseline sync would take approximately 32–33 hours. That puts the overall improvement at roughly 40% faster, or about 1.67x the throughput.
Where the gains are biggest
The improvement isn’t uniform — it grows as the blockchain gets more recent:
| Chain section | Improvement |
|---|---|
| Blocks 0 – 1M (older chain) | ~6% faster |
| Blocks 1M – 2M | ~33% faster |
| Blocks 2M – 3M | ~37% faster |
| Blocks 3M+ (most recent) | ~40%+ faster |
The part of the chain that used to take the longest is now the part that benefits the most.
What changed under the hood
The optimizations target two areas of the block verification pipeline that had become increasingly expensive as the chain grew past Hard Fork 12:
Redundant weight median recomputation. Block weight limits are calculated using a rolling median of recent block weights. The old code recomputed this median from scratch for blocks it didn’t need to — particularly during the initial block cache build and for blocks in the middle of large sync batches. These calculations now happen only when actually needed.
Smarter cache validation. When looking up historical block data, the old code re-validated cached entries using a full hash comparison even when a simple height check was sufficient. The new code skips the expensive hash lookup when the block height already confirms we have the right entry.
Neither change touches consensus rules — they are purely internal performance improvements with no effect on how blocks are validated or the chain itself.
These improvements will ship very soon, alongside wallet restore speed improvements and several other fixes, but this is only step 1. More significant sync speed improvements are coming in Hard Fork 13.
