Bitcoin Forum

The synchronization of Bitcoin Core has slowed down dramatically. It seems to slow down as it loads more recent blocks (more transactions/volume?). It now says I must wait a week for it to load (46.36% loaded, 0.32% per hour, and 7 days to completion as of writing), but how do I know that Bitcoin Core won't slow down further with ever increased activity? Are there methods in use that can speed this up? All feedback is greatly appreciated.

If you have a lot of RAM (4 or more), you can open the bitcoin.conf file and add the following line:
where <n> is an amount of memory in MB. If you have 4 GB RAM, I suggest you set it to 1000 so dbcache=1000. If you have 8 GB, I recommend 4000. If you have more RAM, you can set it to be higher, but after around 8000 setting it higher stops being any more helpful.

I am syncing my second Bitcoin Core in the last week or so.

The suggestion on adding the -dbcache=nnnn is a good one.

Assuming you have at least a "modern dual-core processor" (Intel or AMD), at least 4GB RAM and and a fast HD or SSD, then it should complete in less than a week on a "high speed" home internet connection (e.g. a cable modem).  My first attempt was about four days, but the computer was only on half the time.  That's my experience anyway.

Also, the speed of your Internet connection is a big factor.  If you have ISP enforced limits on your downloads, or data caps, then that is a factor beyond your control and you will have to live with it (or get a different ISP).

If you don't want the ENTIRE Bitcoin blockchain, I've heard that you can also download just part of it with the -prune=nnn command.

I have not tried that myself, because I am wanting the full blockchain, but I've seen it mentioned as one way of speeding things up if you want to setup Bitcoin Core.   Might search around and see if there is more relevant info on it.

https://en.bitcoin.it/wiki/Running_Bitcoin

It is actually more CPU bound than network bound... (You'll most likely find your network is hardly being used, while your CPU is being hammered). Crypto hashing when verifying the blocks downloaded is generally the bottleneck, so the speed of your internet connection is largely irrelevant (assuming you're not on dialup :P)...

When running with pruning switched on, you still have to download the entire blockchain... that is to say, you will still need to download the 130+ gigs to get it "synced". However, it doesn't store all 130+gigs on your disk, so the "available" storage requirements are a lot lower.

What's your computer specs? Have you tried any hacks posted above (though it is 2 years old already)?

Sharing data is one of the options but it requires trust between you and the other parties. Not an ideal solution but somebody has done it IIRC. It might be a good alternative if you have a trusted friend. If not, be prepared with the risk.

I've already had some experience with copied Bitcoin data directories. With my downloads speed (~20Mbit/s), it takes about 24-48 hours to download the entire blockchain, but when I just copy-paste the blocks and chainstate folder it only takes an average of 8 hours to duplicate it (I used cat-6 ethernet connection).

Once a new Bitcoin core installation is completed, I only run the Bitcoin-Qt for a few minutes to start sync, get a few blocks and just get bitcoin's data directory created, then I shut it down and deletes the blocks and chainstate folder in bitcoin's data directory. For the missing folders, I copy the blocks and chainstate folder from my other PC which runs a full node and paste it to bitcoin's data directory in a new node (laptop).

If you want to copy-paste the wallet.dat file too, you should start the bitcoin core with -rescan option, and when doing copy-paste things make sure the bitcoin core in both nodes has been shutdown.

Useful tips, thanks for sharing.