chill man, only 2 people advised against it... and they are perfectly entitled to express their opinions.
Anyway, on to the thread, i used to have water cooling, it was fairly good, but to dramatically lower your temps you do have to pay out quite a bit.
I havent kept up to date with watercooling, but hopefully i can give you some info.
Manufacturers like DangerDen are pretty much the best around, they make the best blocks aswell as pumps and rads. Also, if you are looking for performance, don't buy a watercooling kit. They are overpriced and aimed at n00bs who know nothign and wont expect anything great. This is not what you want.
I used to have a passive water cooled system aswell, meaning there were no fans at all, the water was cooled in a giant rad passively. It's a good idea, but it didnt really work all too well. Temps were about the same as my idle air temps.
Zalman have since bought out a second version of their passive watercooling setup, called the "Zalman Reserator 2 Plus" or something along those lines, i hear its very good at cooling but its also a bit over priced.
Common misconceptions:
- Dont buy two pumps thinking you'll get twice the water flow rates and hence twice the cooling capacity, this is wrong, all it does is theoretically double the head pressure on any joints in your system, which ultimately equals dead components (hehe).
- Don't buy two radiators thinking that two rads will provide twice the amount of cooling and make your liquid twice as cold, this is not the case, yes, dual rads would provide twice as much cooling, but by adding the second rad you are slowing the water flow rates by half, so any one unit of liquid will stay on top of the CPU, GPU, NORTHBRIDGE for double the amount of time, meaning that it will pick up double the amount of heat. So double cooling time, and double heat, actually equals out to nothing, so all it does is... nothing?
- Don't buy bigger tubing just because it looks cool. Bigger tubing has a higher capacity and hence needs a larger pump to puch the water/liquid through at a reasonable rate. If you dont buy a larger pump but still insist on buying the big tubing, then your water flow rates will be crippled and you risk overheating things due to lack of heat dispersion. On the contrary, don't buy tubing that is too small, doing this will increase flow rates if your pump can handle it, but also it will DRAMATICALLY increase head pressure in your loop. This is quite possibly the biggest thing for you to worry about.
Things to note:
- Water and air expand when they get hot. Firstly you shouldnt have any air in a closed loop water cooling system, so we'll rule that one out. But water still stands. Your loop may be at a perfect pressure and a perfect flow rate at system startup, but after a 3 hour gaming session when your CPU has been load-ing at 40*c the water will have expanded... You do the math on that one, higher colume of water in same capacity of tubing = higher pressure and thus lower flowrates, both of which you dont want. To an extent there is no real way of combatting this. Some people say adding a proper coolant to the mix helps, but im not sure. Best thing to do is make sure those joints are well and truly sealed when you put your system together...
Tips:
- Make sure you do a full test run over the course of a day outside of your PC, rig the entire loop up, fill it with liquid and turn the pump on, sit it somewhere like in the bath or outside on the concrete or something and just wait... any leaks, splits or problems will become aparent in this stage
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Hope all of that helps, it took a while to type up so... lol

dragon2309