(1) The Max temp for the Q8300 is 71 C, and I believe that at 80 C the CPU will throtle back to protect the CPU.
(2) The most likely cause for lower temp on CPU1 is better thermo contact between the CPU and the HSF. You could remove the HSF, remove the thermal paste (use alcohol, preferably 91%) and reapply - Use artic silver 5, and just a small amount (about the size of a grain of rice) and spread thinly.
(3) Your ambient room temp is high and will cause higher than normal core temps. Normal room temps is around 22 -> 25 C.
My recommendation is to replace the crappy Intel HSF. Here is a link for comparision. As you can see there is a considerable difference between a Hyper 212+ and the stock HSF. There are others that are just as good as the Hyper, just used as an example.
http://www.frostytech.com/articleview.cfm?articleid=2206&page=5
The silent 1156, lower cost ($30), not as good as others, But sill LOWERED temps by 7->8 C over stock
http://www.overclockersclub.com/reviews/thermaltake_silent_1156_/4.htm
(4). It appears that you cpu fan is at max. What other fans do you have. At a min you should have one at the back, blowing out, and one in the front blowing in. To check if your case has good air flow remove the side cover - Good case airflow you will only see a few degress drop. You could also get a better (higher air flow) fan for the rear.