Honestly, my hashrate is pretty low on four boards.   I'm using a 300watt powersupply, which should be good enough, yet only getting 58gh/s from four boards. This seems mighty low to me. By my calculations, I should be getting around 70GH/s. Maybe it's my powersupply? Overclocking is a no go as well. I'm setting my clock speed to 40 for my blades, even 42 doesn't work. And it doesn't just error, it plain won't work. I'm directly connected to usb ports, no hubs here. I am also using a masscool 120mm fan blowing down the heatsinks, so no passive cooling here.

Slightly disappointing, but in a fun way. Now I get to troubleshoot something. I've already discovered the cause of my libusb errors (usb3 is no beuno).

In response to why the bitfury heatsinks are on the bottom... That's how these chips are packaged. The heat transfer pad is actually on the bottom of the chip, so you connect to it through a transferpad in the PCB. BFL just did it wrong. And you are seeing the bitfury chips. They are not under the heatsink...