Hi all!

I'm building WC loop of two blocks CPU and VGA:
CPU (Max TDP 95-110W)
VGA 5770
NO OC

So I was wondering if anyone can give me an advice on some questions...
After I ave read few post from here, I decided which tubing I should use (1/2 ID), if I'm wrong with this choice - please, correct me.

1. Would a single 120 rad be enough (i.e. DD Stealth GTS 120) with Noctua fan @ 900 rpm

2. Would OCZ Hydro 500 pump (500 l/h) (or same from EK or DD)would be enough for such loop as i'm for the most silent/price ratio. Is it ok to slow down it even more to make less noise.

3. Is this loop setup correct Res-->Pump-->CPU-->VGA-->Rad, couse I've read a few posts were some recommends to use rad after pump as it heats up water a little.

THX in advance.

the radiator is on the end, the cpu gets the fresh water from the pump first, anything else in is in the middle. VGA cards take a LOT of heat and are fine so it doesnt matter there. Also, the water is passing by so quickly that it is not that hot going from one component to another. It slowly gains heat.

Now, that being said, the most important thing is NOT the pump.

This advice is key to making a system more silent and cheaper. The pump helps to compensate for not having a large radiator. However, just get a larger radiator, biggest possible that holds the most water. I do not know the exact radiator you are talking about, but I would guess that a radiator that can only hold 1 120mm fan sounds small. THe bigger the radiator the easier it is to make it silent. YOu could just turn on 1 fan on a 3 fan unit and it provide excellent cooling.

edit: I just looked at the radiator. It is not designed to quietly cool 2 major components. I would get a bigger radiator and sit it on top of my case.

THX a lot for an info as for the start.

I have an Lian-Li PC-B10 case. So there's only two options with it: use a standard back fan placement or to mod a case for a top or bottom 2x120 rad placement. Though I like the minimalistic look of the case so I'd like to keep up with a single 120 rad. Didn't though it could be a major problem as all components are @ standard speeds. Thermaltake and Asetek offers their kits with only 120 rad, offering an VGA block as an option. I also read an newbies guide topic ) (you never know where the gold lies) where it said to use as large radiator as possible. So I'm a little confused...as for the technical part - evrth. is clear - large radiator=more heat dissipation, but then comes thermaltake and asetek with the use of only 120 rad.

Any thoughts...

The sort of double-circled 120 rads (i.e. Black Ice GTX120). Maybe I can get use of them?

I'd say that prio 1 is to have the reservoir just before the pump. Prio 2 is to have the water rotate in order radiator -> CPU ->
GPU -> radiator, but it doesn't really matter where in this loop the reservoir/pump combo is placed.
Bigger radiator won't make it cheaper, but it definitely will help in reducing the required fan noise.
Asetek rated their single radiator as capable of handling up to 400W, which is probably true as long as one doesn't expect more than "won't overheat when a noisy fan is used".
Unless the room temperature is very low I don't expect a 900rpm fan to suffice for cooling your components. It should rather be a 2,900rpm fan, at which point we're well away from "quiet".

There are really two ways to reduce the need for noisy fans:
1) Larger radiator. Possibly placed outside the case, if you want the case itself to stay neat.
2) Larger reservoir (and thus more water in the system). One key advantage of water cooling is that it carries a large thermal inertia that makes temperature changes in the system much slower than with regular heatpipe cooling. With heatpipe cooling you need to cool off the near instant thermal power, whereas with water cooling you just need to cool off the average power taken over some time, and the more water the longer this averaging time "window".
In normal operating conditions you rarely have the CPU and GPU operating both simultaneously at 100% for more than a few seconds at a time, so averaging the work load over several minutes will result in a considerable lower value. With a water volume like 10 litres or more, starting at a 20C temp, you can leave the computer running at 100% load for an hour or more without cooling the water at all and it won't overheat...

Cheers
Olle