I am running 4 gridseeds 3 are overclocked to 850 freq and work great on 1 pc. the fourth is on a different pc is overclocks to 800 freq.
no controller needed but it varies from motherboard to motherboard. the asrock z77 ite-x tiny mobo that could is running
3 gridseeds -------------------3 open cpuminer programs freq 850 gives about 390kh
13 antminer u-1's ------------1 custom cgminer for antminers freq 0981 gives 2.0gh
1 redfury ---------------------1 bfgminer runs the stick at 2.4gh
1 r9 290 gpu --------------------gi miner runs the r9 290 at about 760kh
pretty good for a 2 year motherboard running none stop since aug 2012 when it mined btc with a hd7970.
I have 5 pc's running have just tested the gridseeds on 2 of them and the asrock is really good.
the bottom 3 all run on the asrock and you can use a 12 volt 2 amp power brick for each one if you only mine ltc