Nearly all HU's have built in memory for preventing skipping. Even the OEM decks we produce have memory built in. As for Hard Drives, they are more prone to skipping than a cd deck. The Hard drive is also more prone to failure from excess vibrations. If you want to ensure your deck won't skip, the best bet is a good install. First, ensure you have the rear support screw in the deck and making contact with the car frame. If possible, strap the HU down. Third, your HU operates better at a slight tilt. Normaly 5-10 degrees. Unfortunately, this is not always possible due to the dash.