No solution, just a workaround.
double click the current font name to highlight it.
start typing the name of the font you would like to use.
When the balance of the font name is highlighted, hit return.
Note that this is actually faster than having the computer render all of the different fonts in the scroll list.
I have been doing this for the past 6 weeks, and don't miss the font list a bit.
Hope this helps.
Try this turn off Font Preview and if that doess not work Try turning of Enable Missing Glyph Protection if that does not work turn off both in the Illustrator preference.
It is just a guess.
