1080p TV image grainy since moving from genuine Dell replicator to Targus ACP70AUS
 

I have purchased a new DELL XPS12 with Windows 8. It does not come with a port replicator so I purchased a Targus ACP70AUS replicator. The problem is that the image on the 32" TV I use when at the desk is very grainy compared to previous. I am using the same HDMI cable as previous and if I remove it from the Targus unit and put it back into the:confused: original DELL replicator the image is crystal clear. I am using the latest DisplayLink software. Can anyone shed any light on this as I have resorted to using the old laptop when at my desk which is not acceptable long term.