Run a good benchmarking program to stress test the CPU and system. Suggestions are:
CPUID PC Wizard 2010 (free)
AMD N-Bench 3.1
FurMark: OpenGL Benchmark and Stability Test http://files.extremeoverclocking.com/browse.php?c=1 Just a few to get ya started.
What I was saying is that you did more than a 0.5 increase.
Your "Core Speed" in CPU-Z shows 3609.2 MHz which is derived from the Bus Speed (200 Mhz) multiplied by the "Multiplier" which is 18.
200x 18= 3600 Mhz.
Working backwards a 0.5x step decrease would result in a 3500 Mhz core speed. Which isn't the same as stock. Stock multiplier is 16 aka 4 steps under what you're currently at.
If your temps stay in the same region they are in your screenshot UNDER STRESS TESTING and you dont BSOD...i'd call it safe/stable. Up a few posts is recommendations for stability testing...I prefer prime95 (in short bursts not the 24 hr+ burn in since u only did multiplier increase) or 3dmark. Watch the temperatures during the testing and check the maximum. Not sure exact 'accepted' maximum but aim to keep it below 70 under stress. Its unlikely you will ever achieve the same temperatures in real world use as during stress testing so take everything with a grain of salt.