This is the Monoprice 24-port USB hub. I don't have it in front of me right now, but I think the power adapter for it is 12V at 4A = 48W. The Gridseeds are powered using 12V at 7A = 84W power bricks. Each one powers 8 Gridseeds each, and the Gridseeds run in scrypt only mode. I purchased the 20x Gridseed kit from Zoomhash, 4 of them.
i'm not sure but i dint think thats enough power on the 5v Line to power all the gridseeds.
I've tried 4 different USB hubs and it looks like the max number of Gridseeds I can get running at the same time is around 7-9. This is using the Raspberry Pi across 3 different distros (Hashra, Scripta, Zoomhash). The hubs were:
4-port USB hub - 5V @ 1 A adapter, all 4 Gridseeds working
10-port USB hub - 5V @ 1 A adapter, 8 Gridseeds working
10-port USB hub - 5V @ 2.5A adapter, 8 Gridseeds working in Scripta, 9 Gridseeds working in Hashra.
Monoprice 24-port USB hub - 5V @ 4A adapter, 7 Gridseeds working in Scripta.
So I don't think it's related to the power.
