CPU-Z results

I noticed that when I run CPU-Z on my system, under the "CPU" tab, the "Voltage", "Core Speed", "Bus Speed", and "Rated FSB" all change by small amount every few seconds. Its usually a difference of 0.1 to 0.3, but sometimes the number will jump by 4 or 5. For example, my CPU is rated at 2533.0 mhz, but CPU-Z will vary from around 2530.0 to around 2535.9. The other categories I mention also do this. I'm not overclocking anything. My system has been running very well, no unusual errors or crashing, but I'm wondering if these fluctuations are a sign of failures to come. What do you guys think?

That's the BIOS, jittering it to avoid interferences. The option was called spread spectrum or something. It's alright.