CoreTemp is accurate for temperatures - as are RealTemp and CPUID's Hardware Monitor (recommended). You can get one of the others to crosscheck if you'd like.
Use CPUID's CPU-z to watch frequency and other pieces of information.
Your temps are NOT a problem. You can drive your cpu at 100% using Prime95 Stress Test, and CPUID's Hardware Monitor to watch the temperatures. As long as the core temps level off before hitting 80C, you're OK. If you hit 80C, a better cooler and/or case may be needed for long-lasting 24/7 use. Nothing you run will drive your cpu as hard as this test.
You can download the latest versions of all the utilities mentioned from here:http://forums.tweaktown.com/gigabyte/30530-latest-overclocking-programs-system-info-benchmarking-stability-tools.html