Usually the old in/out is such that I've never had a problem. You seen to want to create a new way of cooling so my advice is to try your idea, measure the temps and then try the other options. I know some may want to model this but I find modeling is expensive and time consuming compared to the old fashioned use the usual setup and measure it.
Bob
im going to do a positive pressure system when i get my new case however the ratio of air in/air out is very dramatic. it would be around 250:100 [in/out] and im not sure if it would be counter intuitive to have too much pressure in the system. what are normal ratios of air for a positive pressure system?

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