Be warned.

When you upgrade from windows 8 to windows 8.1 it is actually a complete windows update equivalent to going from windows 7 to windows 8.

In doing so it blasts away a number of your settings that you may not have thought of.

When I installed my Samsung 830 SSD in my laptop I used Samsung magician to optimise and change the settings that are not required with SSD drives.

I did things like:

1. Disabled Pre-fetch and super-fetch
2. Turned off scheduled defrag
3. adjusted my pagefile down to certain limit
4. turn off write-cache buffer flushing

After windows 8.1 is installed all of these settings are lost. I found out much to my surprise as a defrag had been executed on my machine.

Here are a few articles that talk about all the possible optimisations, the first is from microsoft;
Windows 7 & SSD: defragmentation, SuperFetch, prefetch

Can You Get More Space Or Speed From Your SSD?