For me, Spector is not a tool for debugging performance problems, but for debugging rendering problems. Spector doesn’t provide timings, for example. While it can also help you debug performance problems (by looking at the draw calls, you can see if you’re generating too many renderings, for example), that’s not its primary purpose IMO. PIX can be used instead (Windows only), if you want to see the precise times of the different graphics commands.
PIX could be useful in this respect. You can see a screenshot of its output in this post :
If you’re interested, here’s a github gist that explains how to install it with Chrome : Using PIX with Chrome Canary · GitHub