I took a screenshot of HwInfo running on both systems for comparison.
As you can see, the Athlon II X4 630 shows a CPU 0 temp of 16-22c and a CPU temp around 10c higher at 27c.
The Phenom II X4 955 shows a CPU 0 temp of 32-35.5c and a CPU temp of 23-27c. Under load at 3.6Ghz, it was hitting 50c+ (depending on the fan speed it was 55c+ as I was trying to get the fan as quiet as possible whilst keeping the temps acceptable). I've no reduced the OC to 3.5Ghz and with the fan at 1300RPM it keeps it under 50c, around 46c mostly under load. Whether it's normal for it to get to 55c+ at 3.6Ghz or not I'm not sure but I've read several places to keep it under 50c and others manage 3.8Ghz or higher, so I can only presume that either their heatsinks are more effective or the CPUs are and generate less heat.
Both PCs show motherboard temps about the same, in the mid 30's.
EDIT: Perhaps I can lower the Athlon temps even more as I notice it's running at 1.4v. As the Phenom works fine at 3.6Ghz @1.3v, I imagine the Athlon could manage 2.8Ghz at less voltage.