How to slow down my DVD burner to 1x on RecordNow Max

[staxx75]

Hi I have a Sony DRU-510A burner with firmware 1.0F. I just bought some Ritek DVD-R 4x speed and I am using REcordNow Max 4.5 to burn some .iso images. The thing I am noticing is that even if I set the burn speed to min, it still burns the image at 2x. (It took approx 20 mins for a 4 gig image). I would like to know if anyone knows how to change the burn speed to 1X. I have downloaded Sony's Drive Speed Selector and I am skeptical about using it to burn DVDs since it runs in the background. Any info is appreciated.

Thanks