Product dimensions of the GeForce GTX 1080 Ti Turbo:

Length 26.67 cm
Width 11.12 cm
Height 3.81 cm

I think the 970 GTX is much shorter, so it might be tight!

I ordered and installed the card, it fits perfectly. Attention: 2nd power cable is required

Min. recommended system power 600 W
PCI-E 6Pin 1 x
PCI-E 8Pin 1 x

Do you have this in your system?

Also, you could post your current setup, if the current hardware isn't that strong, then your PC isn't using the 1080Ti's potential at all. (Bottleneck)

I would recommend the gtx 1080Ti mini from zotac with this card you will probably run into space problems especially since it doesn't have the best cooling performance of the 1080Ti models.