I started download the bitcoin blockchain on a 250GB hardrive with prune=0, txindex=1 on bitcoin.conf file. I downloaded like 95% at a rate of around 10% per 8 hours. I didn't have enough free space so I enabled pruning prune=5000 and disabled txindex with txindex=0 on the bitcoin.conf file. Then I relaunched Bitcoin. It started back at the beginning of the chain and is now "processing blocks on disk".

The thing is, it's now progressing at 3% per 8 hours, versus 10% before when downloading the blockchain for the first time without pruning and with txindex. Does anyone have an idea of why it's taking so much time ? No change in hardware or internet connection, same laptop, same hard drive, same wifi connection, using Pierre Rochard Node Launcher v5.6.0 and bitcoin-qt version 0.17.1.

Also, changing the dbcache value has no impact on the speed of processing blocks on disk. The only change in the debug.log is : 2019-02-21T19:20:05Z Prune: UnlinkPrunedFiles deleted blk/rev (00532) and then the cache refreshes and restarts empty.

From what I understood, it may be because I disconnected my drive and bitcoin-qt is revalidating all blocks. Could it be that this takes more time due to the absence of txindex ?

I looked everywhere but couldn't find more info. Any help would be very appreciated! Thanks