DVD Ripper video quality drops when using cuda to encode

[bolter]

I am running windows 7 64 bit and the latest QT version of DVDFAB. Has anyone notice a drop off in video quality when using cuda to encode. I have a GTX 560 TI video card and when I run CUDA to decode and Encode a dvd to MKV 264 I get 320 FPS but picture quality is unacceptable (Medium to major blocking) But if I use CUDA to decode and software to encode, I have a marked improvement in picture quality but FPS drops to 150. Yes I have the latest drivers for the card.

Any ideas

[signals]

If you are not encoding from a BDMV folder on your hard drive, your optical drive perhaps can't keep up. The developers have said since day one with CUDA that optimum quality will be obtained with the Software setting, but I have never seen as much difference as you describe.