nono now i run linux server in there i have edited udev rules and run also smartreadermode like you!
but half year ago my cccam-server was dm8k!
parallel i had run dm800 with 7smargos as oscam server(only as card-server to run special cards like paired nagra ones) and connect to dm8k!
therefor i can say that power of box is no problem for 3 or more smargos!
CCcam shouldn´t be also the problem!
and the funny thing is,my 800 was still on OE1.5 (BH 0.10) as i run these 7smargos on the dm800!
ok,that not helps you!
but try following,
disconnect hub from box(plug out usb), boot up box still it is fully on(CCcam started and running)!
after its running reconnect the hub to box!
after that