Quick watercooling question

My watercooling setup is almost ready to go, its been running 2-3 days in the case leak free, so I'm almost ready to put the hardware in there ;)

One question though, I have the rad mounted in the top of the case with a 120mm fan above and below it ..... these fans are not identical, but are both approx the same cfm (89) and on a rheobus. Will it matter much that these fans are not identical and should they run at approx the same speed, so that the one pulling air through the rad is pulling the same amount of air as the one pushing air through it, or can they be run at different speeds?

I think I know the answer to this, but would like a second opinion as this is my first attempt at watercooling .......

Hopefully I'll get my Prescott below 60C today :D

The only problems you might get is shifting frequency humm as the fans fight each other but carefull adjustment should get around this problem.

Have fun, my watercooling has been in for >1month now and I love it dont have to worry about how hot it is outside.

GateKeeper

You will get better performance from the fans if they are both pulling. Pushing does not work well for axial fans.

And you cannot tell just from the CFM what the fans will be like together, you need to have a static pressure graph.
If they are both pulling through a non-restrictive object (e.g no object) they will then be near enough there full CFM rating, and the fan with less CFM will just reduce it.

However when through a restrictive object (e.g rad) one fan might only be capable of 10cfm at that pressure level while the other could do 30cfm. In this case the slower fan (with no restriction) will usually give better pressure and so push more, this is ofcourse assuiming they use the same amount of power, which they probably wont.

read this

It has been proven that running fans serially gives very little performance increase over just one fan. You just get more noise :)

No you get more static pressure ability.
Ofcouse just waste if theres no restriction.. and that depends a LOT on the rad - sometimes two fans will double the airflow for example.
As I dont know what rad he has (and therefore what the restriction is) I suggest he trys it and finds out.

Anyway both fans pulling in series will do a lot more than one pushing and one pulling in series.