A suspended Eheim 1048 insolated in foam was still louder than a nexus 120mm at 6v. So that would be around 500rpm, which is where i run my fans at on my air cooled rigs.
Also every WC system ive seen, even yours that was linked in this very discussion, has obvious bubbles, no matter how much you try to bleed them all out you never can get them all, and the bubbles make an audible noise.
Have you got any links that measure how much noise is created by bubbles please?
Looking through Google and the Xtremesystems.com forum I didn't find much beyond passing references. There are lots of discussions of waterblock hot spots caused by air bubbles but nothing specific about how much noise bubbles could create.
The specs for the external Eheim 1048 pump are:
Pump Output Approx (l/h) 600
Del.head approx Hmax (m) 1,5
Power Consumption (W) 10
The specs for the submerged Eheim 1000 pump (as used in the Zalman Reserator 2) are:
Pump Output Approx (l/h) 150-300
Del.head approx Hmax (m) 0,5
Power Consumption (W) 5
When submerged within a Zalman Reserator 2 the Eheim 1000 pump seems quiet. It's a lot quieter than the single Scythe SFF21D 800rpm fan in my case anyway.
@echn111: I agree watercooling definitely has a place in cooling a hot PC quietly. My PC is partially watercooled nowadays.
I'm not so sure that active watercooling is the way forwards though.
Even Nexus fans at low speed aren't literally silent. Per your previous post:
"In this system, the nexus fans generate the most noise." echn111
If you could get rid of those fans it would still give you a noticeable noise decrease.
When you get down to 1 or 2 fans getting rid of even a quiet fan makes a big difference.
I've never actually seen anyone showing a watercooled Zalman TNN500AF case. You could passively cool the Core 2 Quad CPU via the case and then you'd watercool the 8800GTX graphics card via an external Zalman Reserator 2.
Now a completely fanless Core 2 Quad/ 8800 GTX system would be cool.
My current PC is moving in that direction but using a standard Antec Solo case it still needs one exhaust fan.
It's fairly quiet but is still clearly audible when there's little background noise.
My PC (Core 2 Duo E6700 @3ghz, Nvidia 8800GTS 640mb)
It's based on an Intel Core 2 Duo E6700 (10*300, 3ghz) and an 8800GTS 640mb card (core 648, shader 1600, memory 1000).
The CPU is passively cooled by a Scythe Ninja rev A heatsink. The graphics card is cooled by a Zalman ZM-GWB8800 GTS VGA Water Block connected to a Zalman Reserator 2.
It runs quite happily with a single Scythe SFF21D 800rpm exhaust fan. The Nesteq PSU is in semi-fanless SSM mode so the fan doesn't spin normally).
Temperatures aren't too bad: (Different room temperatures as I've copied and pasted the results from earlier posts).
At a room temperature of 25.5c
CPU idle: 36c approx (using Intel Speedstep 6*300, 1.8ghz)
CPU 100% load: 74c approx as shown by coretemp (The load temperature showed as 72c in Intel TAT tool).
(Loading was one hour of Intel TAT tool on both cores):
In actual use the CPU temperatures are nowhere near these synthetic numbers. In practice when gaming etc the CPU hardly ever goes above the 60c mark.
Graphics Card Temperatures
At a room temperature of 24c:
GPU idle: 37c (Underclocked to core 100mhz/shader 300mhz/memory 400mhz)
GPU 100% Load: 56c
(Looping the first 3D Mark 2006 Shader Model 3 benchmark (the airship and giant sea dragon one) for an hour. This is at default 1280x1024 no AA.)
This should be loading the card fairly well:
In actual use the GPU load temperature when gaming tends to vary between 50c and 56c depending on how stressful the game is.