I am using Windows 10, Mist Wallet 0.7.2 which includes geth v1.3.6, a non-SSD hard drive and ethernet connection to 16Mbs modem.
I had incredibly slow syncing of the blockchain, even with 25 peers and was actually having to to quit and restart Mist just to download another few blocks. I had installed the Mist Wallet for Win64 from here, which also includes a CLI called geth. (nb. apparently x32 editions don't contain geth?)
I followed numerous different recommendations, however none worked until I deleted the blockchain data using geth and kicked the whole process off again.
Rather than using the Mist sync process, I removed the chaindata and then ran
Opened the cmd prompt
Navigated to the directory containing geth.exe and opened it
Copied the file path from the bar Explorer
cd path/to/geth (replace path/to/geth with what you copied) and hit enter.
geth removedb and hit enter.
Once the blockchain was removed, I ran
This above is also described here.
The download has now got to block 500,000 in 30 minutes which had previously taken 3 days!
If you are on a Mac, you would do this...
Right click on the ethereum-wallet.app and select 'show package contents'
Open 'contents', then 'frameworks', then 'node', then 'geth' and voila.
Then you should right click on
geth and select 'show info'.
Copy the location marked 'Where:'.
Open Terminal and type 'cd `
Other recommended changes to Windows I had performed were:
Whether any of these contributed to it being much faster after the
geth removedb I'm not sure, but each of those may well help you.
The complete download of 1,500,000 blocks finished after about 10 hours, so the blocks definitely appear to take longer to download the greater the block number, due to the increased number of transactions contained in each block.