200cfm fans (blowymatron)

[Pesky Ngon]

im planning to mod some vega 64s. basic idea is to remove obstructions from the inside like the fan and various metal bits. then force air through a duct at the end of the cards, like a server.
im planning to put the LC BIOS on the cards to get the highest possible performance. have no idea if ill be able to get to 1700mhz though.
noise isnt a concern, this is for 3D rendering work. all that matters is the maximum performance i can get out of it while at reasonable temperature, for as little money as possible.

the best 80mm fan I can find does 132CFM.
https://www.digikey.com/product-detail/en/delta-electronics/PFC0812DE-SP04/603-1166-ND/1850535

the best 92mm fan I can find does 175CFM.
http://www.sidewindercomputers.com/depf92drhisp.html

the best 120mm fan I can find does 252CFM.
http://www.sidewindercomputers.com/de12pfexhisp.html

using 80mm fans would make the shroud design a lot easier, but will 132CFM be enough to keep the cards cool (im aiming for under 70degs)?

also, do I need to do anything for the VRMs, like those mini heatsinks? people like Steve from gamers nexus have said its fine just to leave them on air, but actually hardcore overclocking said they need heatsinks. they are clearly both very well read on the subject, so I don't know who's right.

also also, from reading the power requirements, im guessing a standard mobo fan header wont be able to handle these. so my main question is what should I use to power and control one of these fans? and what should i use to power 2 of these fans, if i find out 1 isnt enough.

[boey]

why not waterblock?

[Pesky Ngon]

4 minutes ago, _d0nut said:

why not waterblock?

2 reasons. 1: price should be much much less with this method.

2: reliability. if something goes wrong with this system I need it up again same day because I might have a tight deadline for work. if water leaks and kills multiple components and I have to spend hours trouble shooting and days waiting for new parts, im completely fucked.

 

this is a much more minor point, but I also don't want to have to do all the maintenance that comes with a water cooled system. if its on air I can very quickly clean it with an antistatic brush and im done.