I have been trying to mine Steem using my CPU on my Windows platform now for 24hrs, I followed this fantastic post from: http://steemit.com/steem/@r3b37/steem-mining-for-windows-update-1 but, unfortunately, the initial sync would run pretty fast until about 96%, then the last 4% of the initial sync would literally take 7-8hrs, my computer would run out of RAM, the sync would die, and I would restart the whole process again. I did this 4 times, over 24hrs.
It was enough to make me quit, almost, but I am not a quitter (well, ok, I am trying to quit the smokes right now)!
The solution to this problem is as follows.
To speed up the initial sync from about 8hrs to ~10mins, apply this simple change in your config file:
Find:
enable-plugin = witness account_history
Change to:
enable-plugin = witness
So, delete 'account_history' from that line.
If you use the 'account_history' plugin, steemd requires ~7GB RAM. This was my problem, I only have 4GB RAM.
My initial sync went from taking ~7hrs+ to literally ~10 minutes, and I am now happily mining Steem.
I hope this helps somebody else start mining Steem on Windows. I would like to thank @geoffrey for the tip. What a legend!