biostar tb250btc PRO : prolem on above6 mining mode

[totti10it]

i had the biostar tb250btc PRO
and 4 cards sapphire nitro+ 570 4gb   & 3 cards sapphire nitro+ 580 4gb
it's supposed to handle 12 cards (8+4)
till the 6th card everything is ok

when the 7th is connected and change the bios mining  mode to above 6
.
i can't enter windows
just black screen after the POST  screen
.
.
even updating th bios didn't solve the problem

[totti10it]

I Think i got a solution for this problem
.
.
it;s updating bios and making all settings we need ( above6 - gen pcie 1x - .....)
then installing windows
.by this way the 7th card worked very well
thanx