Control: previous to fan addition, system would run fine, but during heavy graphic usage such as CoH, would occasionally 'hiccup' as the system pulled voltage off the VCore to power the fans to maximum. Once the CPU was cooled, the 'hiccup' would occur again as the voltage shifted back and the fans returned to their normal speeds.
Problem: with added fans (which should have cooled the system), system fans kicked into high every 8 minutes (timed and verified). Under heavy usage (CoH used again), system would kick into high gear once game had been on less than two minutes and would continue to run on high until game had been turned off for 2-4 minutes. Hypothesis made that new airflow path is pulling warm air over the sensor, causing inaccurate readings. Add fan and temperature monitoring software to see what's what. Discover fans are running slower than general opinion feels they should (approximately 55% of maximum).
Present: CPU fan set to run at 85% of maximum, rear fan at 100%. New fans are constant speed, so no change there. System ambient temperature sensor reads an average of 97 degrees (CPU running around 109). No "shift" to high speeds seen under normal usage. CPU fan turned up to 90% of maximum before game turned on, and then CoH run, while keeping an eye on the time to see how long it takes for the tick-over to happen. CoH played for approximately two hours...with no high speed shift at all. System ambient temperature sensor reads 102 degrees (CPU about 117) when game shut down. CPU fans returned to 85% when system temp returns to operating temperature, which happens pretty quickly.
Hot biscuits, I may just have this licked. Only issue at this point is that it's a little louder over here than it was before all this, but that isn't a problem, per se.