Different temps across the cores is normal. Core 1 is usually a few degrees hotter than the rest. (It does more work)
The alternating core speed in CPU-Z is just reporting the C1E/Speedstep feature. That too is normal. (When the PC is idle, or under low load it runs at a lower clockspeed with reduced voltage)
It's also common on the Q9XX series for some cores to have 'stuck' sensors that don't accurately report idle temps. As long as they show movement under load, it's not a problem.
Basically, everything sounds normal and as long as the temps themselves aren't too high, nothing is faulty
