The most recent version has additional delays built in to meet ffnet's 
requirements.  It should take that story around 2 minutes to download, and 
that's what I see when I try it.

If it's taking you 10 minutes, I speculate that ffnet is throttling.  Unless 
you have a significant slow_down_sleep_time set in personal.ini, nothing FFDL 
does should be causing it to take that long.

Operating as designed and no further response from reporter.

I have the same issue. I've found that on Windows (64-bit Windows 7) downloads 
are reasonably fast; on Ubuntu (several versions, since I've had this issue for 
a long time) downloads are very slow.
https://www.fanfiction.net/s/3934461/ has been downloading for 11 minutes now.

On Linux, no other application shows this behaviour; I have a high-speed (20+ 
Mbits/s) connection. I've disabled ipv6 support in my OS, as that did slow 
everything down (I'm on ipv4).

https://www.fanfiction.net/s/3934461/  took 13 minutes, another, 
https://www.fanfiction.net/s/2544950/, took 12.

With the sleep times involved these days to keep from triggering the throttling 
at ffnet, those times, while a little long, aren't outrageous.

Downloading both in CentOS6 for me took ~11m and ~7m on Win8.

With some added debug output, it looks like connection times average the same 
within 30ms.  

So, it looks like there is some additional slow down in Linux vs Windows 
somewhere.

I'll see if I can isolate it any better sometime.

Turns out I had different slow_down_sleep_time settings on my linux and my 
windows.

Now that I have them set the same, I'm getting extremely similar times on linux 
and windows.

I've posted the test version I'm using with additional profile timing debug 
output at:
http://www.mobileread.com/forums/showthread.php?p=2781869#post2781869

If you want to check your slow_down_sleep_time settings and try the posted test 
version, posting the job output here, it might tell us more.

I'll give it a try, thanks.

Well, I'm not sure I did it correctly, but I saw no change in speed, 
https://www.fanfiction.net/s/3934461/ took 13m 49s.

1. downloaded zip from linked forum post;
2. found FanFictionDownloader in ~/.config/calbire/plugins
3. moved it elsewhere (a temp directory)
4. copied downloaded zip to said directory
5. launched calibre from the command-line
6. removed e-book from calibre's menu
7. copied URL to clipboard
8. used FF downloader plugin to download and convert

The console output does not contain any kind of debug info, I think:
kofa@eagle:~$ calibre
FFDL:DEBUG:calibre_plugins.fanfictiondownloader_plugin.ffdl_plugin(155):Plugin 
FanFictionDownLoader macmenuhack 
file_path:/home/kofa/.config/calibre/plugins/fanfictiondownloader_macmenuhack.tx
t
Created new window in existing browser session.
FFDL:DEBUG:calibre_plugins.fanfictiondownloader_plugin.ffdl_plugin(725):FanFicti
onDownLoader v1.8.13
FFDL:DEBUG:calibre_plugins.fanfictiondownloader_plugin.ffdl_plugin(760):url:http
s://www.fanfiction.net/s/3934461/1/
FFDL:DEBUG:calibre_plugins.fanfictiondownloader_plugin.fanficdownloader.adapters
.adapter_fanfictionnet(90):URL: https://www.fanfiction.net/s/3934461/1/

===========
 connection time 15.75
===========
FFDL:DEBUG:calibre_plugins.fanfictiondownloader_plugin.ffdl_plugin(933):from 
URL(https://www.fanfiction.net/s/3934461/1/)
FFDL:DEBUG:calibre_plugins.fanfictiondownloader_plugin.ffdl_plugin(1086):title:V
ictus per Reproba Monumentum
FFDL:DEBUG:calibre_plugins.fanfictiondownloader_plugin.ffdl_plugin(1087):outfile
:/tmp/calibre_1.26.0_tmp_w_CUTi/fanfictiondownloader_tCZODR/Victus per Reproba 
Monumentum-firefly5151-2e9wda.mobi
FFDL:DEBUG:calibre_plugins.fanfictiondownloader_plugin.ffdl_plugin(1176):add/upd
ate Victus per Reproba Monumentum https://www.fanfiction.net/s/3934461/1/

After running a download, click where it says 'Jobs' in the lower right corner 
of calibre.  That brings a list of past & current jobs.  Double click the 
finished Download Fanfiction job to see the logged background output for the 
download.

[deleted comment]

Done (log attached).
FYI, using wget (I got the URLs from the calibre log):
FINISHED --2014-03-10 22:42:43--
Total wall clock time: 38s
Downloaded: 53 files, 3,5M in 12s (293 KB/s)
There was a ~5sec 'Resolving www.fanfiction.net (www.fanfiction.net)... 
173.205.184.6' pause at the beginning of the wget run, the rest was fast.

Well, the lookup pause was probably longer, not 5s, as download time was 12s, 
wall clock time was 38s. I re-ran it, cancelled when it started to download, 
and the lookup took 15s.
DNS resolution slowness seems to be ipv6-related, and not calibre-specific. 
wget -4 (forced ipv4) and nslookup / dig take no time to resolve names.

Let's put this on hold until I sort wget out.

FFDL is never going to be as fast d/l'ing from ffnet as wget because there's ~9 
seconds of sleeps added.

But the 'connection time' lines are truly that--just the connection times.  On 
my systems, both windows and linux, those averaged around 330ms.

Since yours are in the neighborhood of 5s longer and you see the DNS takes 
that, I agree that it's likely a DNS issue for you.

Why it would be resolving on every hit instead of caching is probably a related 
question.

If you want to prove whether it's specific to calibre or common to python, I've 
attached an extremely basic python url fetch program.  Just give it a file 
containing only a list of urls.

Still no response from original poster.

Second poster's problem appears to be a DNS unique to them.

Closing issue.