Is my processor running too hot?

[Ilmater]

I'm using the following:

Scythe SCSMZ-1100 92mm Sleeve CPU Cooler
Athlon X2 5400+
MSI K9N Neo-F V.3 nForce 560 MCP Motherboard

I lapped the bottom of the cooler, used some Arctic Silver Ceramique that I had. It was two or three years old, but the cap was always on.

I can't see why it would be running that hot? Can anyone help?

Forgot to add, it's running at stock speeds.