The blinkly lights has nothing to do with power or communication. It's an issue with the temp sensor, which is connected to the onboard microcontroller, which is not affected by voltage or USB anything.
Just to be double-clear, the white light is flashing while hashing on all of them, but on two of them the red volt-setting LEDs are blinking?

Without ASICBoost, the theoretical peak speed is about 575MHz (~800GH) on a wide-open USB bus. If the bus is shared out with something else and/or the processor is slow and timings aren't perfect, it'll be less than that. See the guy above whose pod, without AB, only saw about 500MHz. This is a USB limitation completely independent of core voltage setting. You may need to get a system working with AB, or plug into a more powerful controller, to get stock speed.