Yes, I'm running current chrome on current macOS with a GeForce GTX 980 Ti (6gb vram) and 16gb ddr3. CPU utilization is 75% on all four cores and when drag-scrolling around the map I don't get more than 10fps. EDIT: I measured it with the developer tools. The performance is not significantly different with them open. I have a feeling you'll never be able to solve this without going to webgl because canvas drawing is slow af. I highly recommend checking out Three.JS. I wouldn't be surprised if you could port the entire game to using it in a week or so.