IMO, speed is way over-rated. I've killed plenty of critters with old vertical recurves and compounds that were rather slow (like 200fps) or less. My current Xbow runs about 330-332 fps. Is it the fastest? No. But, it's very well built, accurate and has been without issue. It kills just fine. When you increase the speed, you then may have other considerations to deal with (such as noise, potential accuracy issues, increased stress and wear-out of strings, cams or cables, etc.).