usb os and black screen|mac pro 2009 4.1

[EirikStrand1996]

Hi, i have a mac pro 2009 4.1, its got 7gb of ram right now and a ssd and 1tb hhd and a gtx 660ti.
so when i put my usb install os nothing happens on the screen, i just stays black, why is this ?

 

[BillyBobBongo]

Sounds to me like you have a standard PC graphics card in your machine. You need to drop your original graphics card back in, would be either a NVIDIA GeForce GT 120 or an ATI Radeon HD 4870. PC graphics card do not have the necessary EFI to see the 'boot screen'.

 

[orph]

what os is it on the USB stick?
iv got a pc GPU and have not had a problem with booting from USB osx installers or recovery partitions.

just go to system prefes chose the boot drive, click reboot

unless your trying to boot a OS thats so old it wont work with your card?