<p>Sadly Bitcoin-Qt's (and bitcoind's) default DB cache size is very small for systems like yours.</p>

<p>You should definitively add <code>-dbcache=4000</code> (use 4GB of RAM for UTXO-set-database [etc.] cache).
This should speedup your sync significant.</p>

CC BY-SA 3.0
2016-07-22T09:13:25.770Z
2016-07-22T09:13:25.770Z
Jonas Schnelli
<p>By the sounds of things and your fix, I would say that you had a blockchain created by an earlier version of Bitcoin-QT and something in the migration process in making that work with newer versions is causing it to take longer than to download the whole blockchain fresh with the latest versions. It's always advisable to keep a backup of wallet.dat (so you don't lose access to your wallet) but you can dump the rest of the application support directory which is mostly blockchain.</p>

CC BY-SA 3.0
2015-05-22T12:58:09.220Z
2015-05-22T14:07:42.773Z
2015-05-22T14:07:42.773Z
Jay
<p>I've had Bitcoin-QT running for about six total hours, and the rate at which it's catching up is glacial at best. It takes about an hour to advance a week, which would make the process take about 4 days to complete. It didn't take nearly this long on my PC; I started and finished the process while my Mac was still running. I'm running Bitcoin-Qt v.0.10.1 64-bit on a 2011 MBP, 8 GB of RAM, on 10.10.4. Is this normal, or is there something wrong? </p>

CC BY-SA 3.0
2015-05-21T22:48:14.177Z
It's perfectly normal. It doesn't have anything to do with the fact that you're running it on a Mac. If you're feeling lucky, you can stop it and restart it (it will continue where it left off) and hope that it will randomly choose faster peers.
Greg Hewgill
CC BY-SA 3.0
2015-05-21T23:11:55.947Z
I actually solved this problem just a second ago, by manually deleting the block chain and starting over. It's going much faster now.
Jack
<blockchain><bitcoin-core><mac>
Why does Bitcoin-QT not seem to be catching up on my Mac?
Jack
# Why does Bitcoin-QT not seem to be catching up on my Mac?

(Asked by: username_0 on 2015-05-21)

I've had Bitcoin-QT running for about six total hours, and the rate at which it's catching up is glacial at best. It takes about an hour to advance a week, which would make the process take about 4 days to complete. It didn't take nearly this long on my PC; I started and finished the process while my Mac was still running. I'm running Bitcoin-Qt v.0.10.1 64-bit on a 2011 MBP, 8 GB of RAM, on 10.10.4. Is this normal, or is there something wrong?

**Tags:** blockchain, bitcoin-core, mac

> **Comments:**
> **username_1**: It's perfectly normal. It doesn't have anything to do with the fact that you're running it on a Mac. If you're feeling lucky, you can stop it and restart it (it will continue where it left off) and hope that it will randomly choose faster peers.  
> **username_0**: I actually solved this problem just a second ago, by manually deleting the block chain and starting over. It's going much faster now.  

---

## 2 answers

### Answer by username_2 on 2016-07-22. Score: 1

Sadly Bitcoin-Qt's (and bitcoind's) default DB cache size is very small for systems like yours.

You should definitively add `-dbcache=4000` (use 4GB of RAM for UTXO-set-database [etc.] cache).
This should speedup your sync significant.


---

### Answer by username_3 on 2015-05-22. Score: 0

By the sounds of things and your fix, I would say that you had a blockchain created by an earlier version of Bitcoin-QT and something in the migration process in making that work with newer versions is causing it to take longer than to download the whole blockchain fresh with the latest versions. It's always advisable to keep a backup of wallet.dat (so you don't lose access to your wallet) but you can dump the rest of the application support directory which is mostly blockchain.


---

