I don't know if this has been posted yet in this thread but you can overclock it by using google chrome to edit the frequency on the "Advanced Settings" page. The instructions are posted here in the description of this video.

https://youtu.be/XI31hHhvYzA

I've got mine running stable for the past few hours at 675m. I'm getting 14-15k sol. Any higher and I start to lose boards unfortunately.