Actually you are right about the gear drive reducing the rpm's to the pump. The advantage with the belt drive is overall cost and reduced maintenance . Gear boxes are expensive. The gear drive will still transfer heat and vibration from the engine to the pump and they have a whining sound. Pulleys and belts are less expensive to repair and replace. Not many companies use gear boxes these days. As for being compact, Pressure Pro offers the polychain belts on some units that are compact if that is important to you. They are more expensive but very durable. I hope this helps you understand a little more. Never hesitate to contact me when you think I can be of help. As I have stated many times I started out trying to run a direct drive from a tank and just spent good money after bad trying to make it work. I keep repairing the pump. Back then there were not forums like we have now. I know we all think we can not afford to upgrade to the proper equipment only to later find out we spend more in the long run by putting it off. I kept my first machine, a direct drive as a backup. I am a firm believer in having a backup machine. This is another reason I am not a fan of a two gun machine. When it is down, you are down. If you have two machines and one breaks you can still work with the backup. Rance, with me being in the rehab stage from my shoulder consider yourself invited to come spend a day or two with us. That goes out to anyone else interested. The only drawback is I do not tour the Hooter's circuit as I did in the past. LOL! Ron and some of the rest here will agree that I love to teach those eager to learn about this industry.