Why i can use only two grafik devices with the cuda api not three

Hello and good morning External Image

I have a problem with the cuda engine External Image I have three devices on my x58 motherboard and the nvidia controll panel see all of them,but if i will use n applikation as tmpgenc are only the first 2 are available.

Sli is deaktivated!!

On the pictures you see waht i mean :ph34r:

Have anybody n idea what the problem is there?

Thank you already for your fixes External Image