There's alawys some risk. But, risk to the CPU will ultimately come with voltage increases. Just increasing the speed will not change much, your computer will shut down from a bad OC before letting your CPU get harmed. Get HWmonitor to monitor the temps, and run prime95 for 15 minutes. This will show you if it is stable and if your temps will be good at load. Again, if you are not touching voltage, it shouldn't affect temps too much. I'd suggest you monitor your system at load with your current settings so you have some point of reference of temps and are able to compare. You want to stay under 80C. if it gets to 75C stop the test.