The kerf is determined by the size and shape of the beam at focus. That aspect should be independent of power, but with a catch. Higher power with the same beam size can burn a wider swatch due to the extra heat. If you speed up the travel, you reduce this overburn effect. I found the Roly Lasermatic10 advertises an .08mm x.08mm beam. The Genmitsu Jinsoku LC-40 (10w) advertises a .08mm x.06mm dot (not said which axis was .06mm), so the kerf is likely to be different between the X and Y axis. I expect a round dot is better than an oval one. A 5.5w laser uses about 40 watts of power. Manufacturers play games with the advertising, so read the info carefully. Laser output power is what I focus on. Also remember 5.5w is about the most you can get out of a single diode. Multiples of 5 are obtained using more diodes, which all have to be focused to the same exact point. The more complicated the machinery, the easier it is to gum up the works.
