i read about some people having about 150 fps in a blender game on a good pc. but isnt the fps-rate limited to 60?
You can set it up to attempt to maintain 250 fps I think.
In Properties > Render > Performance you can uncheck Use Frame Rate. In this mode it will redraw as soon as it has finished logic, physics and preparation for rendering. This pc redraws the default cube just sitting there about 290 fps.
I think you can increase the frame rate limit somewhere. Keep in mind it is much easier to have a stable 60 FPS rather than stable 150fps.
60 fps is plenty for the appearance of smooth motion. Also Erwin Coumans says he has written Bullet Physics to work best at 60 fps.
When you want to go over 60fps (possibly for benchmarking) you might have to look in to places. First off, Blender limits the framerate. To disable this do as Equip said. Your graphics card might also be limiting you fps by capping it to the vertical refresh rate of your monitor. This is called Vsync and is used to prevent graphical artifacts like tearing. However, if you want to benchmark, you don’t really care about this, so go into your graphics settings and disable vsync for now (make sure to turn it back on later!). By graphics settings I mean whatever tool the driver provides, such as Nvidia Control Panel or Catalyst.