No more spreadsheet results for the moment as I think the results are too specific to my particular configuration.
But I did compare ducting with no ducting.
Core temps might be 1-2C higher with ducting unless it is at min rpm for all the fans in which case it is better by about 7-9C! This is well worth having at min rpm.
Also the HD appears to be 1-2C cooler; I assume from not having the hot air from the cpu being blown back to the HD area.
Looking at my results, I think it is a 'balance' of airflow which makes the difference when there is ducting.
Each of the cpu, top and front fan could be a limiting factor for the other fans
So there is no point in increasing the speed of one fan without the others.
That would explain why at min rpm, there is not much difference in increasing each of the other fans (except the cpu fan)
Overall, I think the ducting is a good thing.
The Coolink 1201 arrived and I did some testing
As a front fan the Coolink is a disappointment.
Even at max rpm, it cannot match the Noctua at lowest rpm for cooling power.
And the Scythe 13 matched the Noctua for cooling power at 1 dba less.
This changes when the Coolink is used as a topfan.
The Coolink doesn't sound quieter than the Lian Li but the dba says it is 1db quieter.
I then put the Noctua black resistor in line and bought the Coolink from the Zalman 5V (650rpm) down to 450rpm.
Now the dba meter is saying the Coolink is at 56.5dba, the quiestest measurement so far for a top fan.
I swap the Scythe 13 back into the top fan position and it reads 59.5.
But is doesn't sound louder than the Coolink.
After doing further testing, the Scythe at min rpm is about 5C cooler than Coolink as a topfan at not much louder noise to my ear.
While hunting around for Scythe Gentle Typhoon reviews I came across this posthttp://www.overclock.net/t/1273923/coug ... e-begin/30
where Martinm210 says "The AP-15s do have issues with harmonics at specific RPM levels, but near as I can tell...nothing comes even remotely close in keeping noise levels as low when rad mounted."
So basically GT are very good when there is a resistance.
So I've ordered a Scythe GT AP14 to go in as a cpu fan cooler.
But further on in response to a question about bearing noise
"Get a syringe or poke a hole in the rear label and squirt some tri-lube in there."
which led me to herehttp://www.overclockers.com/em-spinning ... e-pc-fans/
So I've ordered some sewing machine oil to see if I can eliminate that bearing noise from the Scythe AP-15 I had. I might try that with the other fans I've got
Hmmm ... I wonder how quiet they might become ...