hello. I intend to oc my cpu and gpu. i use a phantom410 case. with a 120mm fan in the front, left side, rear and a 140mm fan on top. my cpu fan is a stock too. so was wondering if i need a better cooling unit. if yes, would air or water be a difference? and can you suggest some. thanks
If you want to overclock, then YES, you should at least upgrade the cpu cooler.
If you are going for a mid level overclock something like the inexpensive CoolerMaster 212 evo is a great option. If you want to go big, the NH D14 is another option, but remember it is BIG.
As for water cooling, you will get people from both sides. I recommend water cooling if you want to move the system allot to reduce stress on the motherboard or if you have a small case that will perform better with the hot air getting out of the case faster.
I own both the the NH D14 and H80i from corsair and to be honest for my system they perform about the same when the fans are set to run at about the same noise level(The NH D14 has has the advantage that even if the fans fail it will not overheat unless the system was 100% stressed. it just has that much surface area). I kept the H80i in just because my case is small and has poor air flow. The NH D14 went to another system with better air flow(this is not to say it did not work good in my first system) and is still working great.
Also note that some liquid cooling pumps seem to have noise issues.
I have a Zalman LQ310 on my video card and the pump is quite loud(sounds like an old hard drive. No matter what I did[within reason, slowing it down does help, but my H80i does not make any sound] it was the same. The replacement was only slightly better.). So this is something you have to factor in.