QUOTE(meazurali89 @ Oct 12 2014, 03:44 PM)
the only exhaust fans at the back of my case should i choose higher rpm to quickly pull the air out or just normal fans rpm is better?

It would be best if all the fans have the same RPM so it would be easier to balance the amount of air to be intake as well.
Do take note of the noise the fans emit too. Fans above 1300 RPM makes audible noise if the case is just placed within 90-120 cm away from you.
There are 2 types of fans you will need to consider which are SP (Static Pressure) and AF (Air Flow fans).
AF are used for exhaust or areas where there target component to be cool does not have any obstacles in between.
SP are used for HDD Cages (Hard Disk Drive) and CPU Heatsink.
The fans I recommend would be either Enermax T.B. Vegas 140mm (L.E.D) and Noctua NF-A14 (140mm fan).
Both fans deliver great amount of air with sufficient static pressure compared to cheaper fans that is priced around RM30 and below.
TB Vegas cost around RM60 (flashy LED, removable blade for cleaning, 1 year warranty) and NF-A14 (saves electricity, 5 years warranty) is around RM75.
This post has been edited by asunakirito: Oct 12 2014, 08:41 PM