<p>When you bootstrap the database of your Bitcoin Core, the <code>bootstrap.dat</code> contains all the data necessary to build the database, but your computer will still build the database from ground up, verifying each and every transaction of each block. So, compared to the regular synchronization you just save the downloading of individual blocks. Once the <code>bootstrap.dat</code> is renamed to <code>bootstrap.dat.old</code> it has been completely imported and can be safely deleted.</p>

<p>Now, in your case, the <code>bootstrap.dat</code> was probably a few weeks old, and your computer is getting the remaining blocks through regular synchronization. It will download one block, verify all content, update the database, and repeat, until the it has caught up to the current state of the network. </p>

<p>For the whole process the bottleneck is usually the CPU, as it's mostly computation, or the harddisk i/o. The necessary download speed is much less than 50mb/s, though it is quicker in total if all data is already available on the computer. It is common for this process to take hours to days.</p>

<p>As Jannes and David pointed out in the comments, synchronization performance will generally be improved with the upcoming 0.10 version due to the introduction of <strong>headers-first synchronization</strong>.</p>

CC BY-SA 3.0
2015-01-11T12:37:43.140Z
Note that the upcoming 0.10 version (now downloadable as release candidate) does away with the separate bootstrap mechanism altogether and will download much faster.
Jannes
CC BY-SA 3.0
2015-01-11T14:32:53.440Z
I agree it will download much, much faster in version 0.10.0 thanks to the headers-first synchronization, but [bootstap.dat is still supported](https://github.com/bitcoin/bitcoin/blob/0.10/src/init.cpp#L430-L443) as well.
David A. Harding
CC BY-SA 3.0
2015-01-10T18:46:07.220Z
2015-01-11T14:37:43.087Z
2015-01-11T14:37:43.087Z
Murch
<p>So I downloaded and installed BitCoin Core X64 v0.9.3 from <a href="https://bitcoin.org/en/download" rel="nofollow">https://bitcoin.org/en/download</a>.</p>

<p>I then downloaded the linked bootstrap.dat torrent and after it downloaded the bootstrap.dat, I moved it into the root of the Bitcoin program folder.</p>

<p>I started the program, and here I am, about 20 hours later and its still synchronizing with network... I've got about 4 weeks left to go.</p>

<p>I noticed in my Bitcoin program folder, my bootstrap.dat file has now been renamed to bootstrap.dat.old.</p>

<p>I'm just curious if this in normal for the time it's taking to sync a downloaded bootstrap file. Not to mention running my CPU at 70% the entire time.</p>

<p>My PC is an AMD 8-core with 16GB RAM, and internet with 50mbps down and 25mbps up speed.</p>

<p>Thanks for any advice.</p>

CC BY-SA 3.0
2015-01-10T15:46:53.253Z
possible duplicate of http://bitcoin.stackexchange.com/questions/11029/how-long-should-synchronizing-your-wallet-for-the-first-time-take.
morsecoder
CC BY-SA 3.0
2015-01-10T16:08:42.083Z
the question you linked as a possible duplicate was posted 2 years ago. It would be nice for a more updated response.
BCuser1233221
CC BY-SA 3.0
2015-01-10T18:48:52.903Z
The blockchain is now a bit bigger, but that other question's answer is still correct, even if it is almost two years old.

@StephenM347: I think it is related to the question you posted, but not a duplicate of that.
Murch
<synchronization><bootstrap.dat>
How come importing the bootstrap.dat to Bitcoin Core takes so long?
BCuser1233221
# How come importing the bootstrap.dat to Bitcoin Core takes so long?

(Asked by: username_0 on 2015-01-10)

So I downloaded and installed BitCoin Core X64 v0.9.3 from <https://bitcoin.org/en/download>.

I then downloaded the linked bootstrap.dat torrent and after it downloaded the bootstrap.dat, I moved it into the root of the Bitcoin program folder.

I started the program, and here I am, about 20 hours later and its still synchronizing with network... I've got about 4 weeks left to go.

I noticed in my Bitcoin program folder, my bootstrap.dat file has now been renamed to bootstrap.dat.old.

I'm just curious if this in normal for the time it's taking to sync a downloaded bootstrap file. Not to mention running my CPU at 70% the entire time.

My PC is an AMD 8-core with 16GB RAM, and internet with 50mbps down and 25mbps up speed.

Thanks for any advice.

**Tags:** synchronization, bootstrap.dat

> **Comments:**
> **username_1**: possible duplicate of http://bitcoin.stackexchange.com/questions/11029/how-long-should-synchronizing-your-wallet-for-the-first-time-take.  
> **username_0**: the question you linked as a possible duplicate was posted 2 years ago. It would be nice for a more updated response.  
> **username_2**: The blockchain is now a bit bigger, but that other question's answer is still correct, even if it is almost two years old.  @StephenM347: I think it is related to the question you posted, but not a duplicate of that.  

---

## 1 answers

### Answer by username_2 on 2015-01-10. Score: 2

When you bootstrap the database of your Bitcoin Core, the `bootstrap.dat` contains all the data necessary to build the database, but your computer will still build the database from ground up, verifying each and every transaction of each block. So, compared to the regular synchronization you just save the downloading of individual blocks. Once the `bootstrap.dat` is renamed to `bootstrap.dat.old` it has been completely imported and can be safely deleted.

Now, in your case, the `bootstrap.dat` was probably a few weeks old, and your computer is getting the remaining blocks through regular synchronization. It will download one block, verify all content, update the database, and repeat, until the it has caught up to the current state of the network.

For the whole process the bottleneck is usually the CPU, as it's mostly computation, or the harddisk i/o. The necessary download speed is much less than 50mb/s, though it is quicker in total if all data is already available on the computer. It is common for this process to take hours to days.

As username_3 and username_4 pointed out in the comments, synchronization performance will generally be improved with the upcoming 0.10 version due to the introduction of **headers-first synchronization**.

> **Comments:**
> **username_3**: Note that the upcoming 0.10 version (now downloadable as release candidate) does away with the separate bootstrap mechanism altogether and will download much faster.  
> **username_4**: I agree it will download much, much faster in version 0.10.0 thanks to the headers-first synchronization, but [bootstap.dat is still supported](https://github.com/bitcoin/bitcoin/blob/0.10/src/init.cpp#L430-L443) as well.  

---

