Strange Render Times

HP Z800
2 x E5620
24 gb DDR3
GTX 980 ti SC+

MOV from Canon 5D to mp4 1080p - One minute video

CPU Render = 00:03:06

GPU Render (Cuda) = 00:03:08


Sun Ultra 40 M2
2 x Opteron 2218
32 GB DDR2 ECC
Quadro FX 5600

Mov from canon 5D to mp4 1080p - One minute video

CPU Render = 00:10:34

GPU Render (Cuda) = 00:02:14

Why this time difference? A 980 ti slower than the Quadro FX 5600?