433MHz at 0.8V is probably about 3A per stick, so your hub is pushing 30W internally. Try setting the sticks to about 740mV and 300MHz, which should draw something like 6.8W per stick; four would then be about 27W total. See if it'll keep up. If you can, plug up first one stick, then two, then three, then four; after each stick, measure the 5V coming out of the hub ports and see if it's starting to drop. If you don't have an inline meter, use the meter you use to check core voltage and measure across the outside two pins on the USB plug.
Awesome! Thanks Sidehack, I'll keep trying and see if I can find the magic combo.
^+1^
What kind of hub?
Sounds like some kind of limit on the power. 2 sticks is not drawing enough to trip the limit, but 4 sticks hit's the limit and some kind of protection cut's the power down (?, just guessing).
It's an Orico 10 port 12V 3A USB 3.0, just like this one on amazon
http://www.amazon.com/gp/product/B00CBEVTKI?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00Maybe it distributes the power per-port so using only four I can't utilize all of the available power??