Airflow is a complicated study. Using smoke is nice but very hard to tell what it's really doing. Best way I know of is high speed video and playback very slowly to see what's happening. I don't have that capability so use remote temp sensors and monitor component temps. Takes time and patiences but you will find strange and amazing results.
X58A-UD3R Northbridge chip runs hot. Stock Phanteks setup NB was in high 70s/low 80s. Took blue covers off and temps dropped to mid 60s. Changed to TY-140 fans and dropped to mid 50s. Lowered fans so flush with top of cooler and mid to high 40s. This was done over several weeks of change and monitor to see what was what. I tried extra fans blowing at NB, built ductwork for fans, etc. All to find TY-140 flow pattern solved all my problems.. CPU is slightly cooler and all sounds slightly quieter too.
Changed TY-140 to TY-143 fans and can tell no difference in 700-1300rpm range. i7 980 stock doesn't run hot enough to tax cooler (CPU @100% = 60c with fans unplugged & 53c @ 1000rpm) so don't know what TY-143's extra rpm (700-2500rpm) will do. Need to get busy and overclock.