I will make this short. I purchased a new Echo CS-590 a few weeks ago. Well in between rain showers I got a short chance to run it. Now I had already performed surgery on the saw. The restrictive module on the muffler has been relocated, and the same for the limiter caps. At first it had hesitation .and lots of it. Now it acts the way I like it. Near instant throttle response. Anyway with a new RS chain on it I put it into some red oak. I had to ease off the throttle. It actually scared me. I have never had a saw with this much muscle. I had before this mission I checked the compression. 175 pounds. Well it again started to rain so I had to head home. For the price this saw is more than I expected .I will mention that I am using pump gas 87 octane with 35/1 Amsoil.