I really have no clue about what noise levels to expect or what noise levels
are unattainable. All I know is my current but old system irritates me, I
want something new and I want to do it "right". OK, maybe watercooling is a
little bit over the top, but I can have some fun, can't I? Or do you really
advise me to stick to fan cooling...
Watercooling is good for extreme overclocking or severe environments,
like the middle of a desert. It has no benefit otherwise. Use of a
higher-end quality cooler, large and with at least an all-copper
baseplate, coupled with a large 80-92mm low-RPM fan on top, can
achieve same or lower noise levels, at lower cost, lower system
complexity, takes up less room in the case, elimination of
water-leakage risk, and lower maintenance. Water-cooling is best left
to those who think having the lowest CPU temp possible is some kind of
contest or have a quest to get the last 3% performance out of a
system, and are of course spending top-dollar on other components like
video card, memory, and SCSI-RAID.
If you really just want to play around with mods and water-cooling is
the next big step, hey, it's your hobby, done right there's nothing
wrong with using water cooling, it just doesn't have any benefits for
normal system, even high-performance ones.
I was thinking of buying a Koolance case with CPU, video and northbridge
watercoolers (and maybe harddisk watercoolers too)
Does that still require airflow over the motherboard?
Reread above paragraph.
Next consider that the same applies to a video card, reduced life if
all you're cooling is the GPU, not the rest of the card.
If you want to spend the time it's not too hard to mod any kind of
cooler or make a bracket to put a large quiet fan wherever you want
it.
Do water pumps really make that much noise?
Generally not loud, but it is additional noise. The same low-RPM fan
used to cool a water radiator could be cooling a CPU heatsink instead,
so water-cooling pump adds extra noise. Again this is only when
considering decent CPU heatsink paired with a quiet fan.
And I am thinking of a "more or less" high-performance system, with a 3GHz
P4, 1GHz of RAM, 2 HDD's in RAID 0, and a decent (but not the best) graphics
card.
It's your call.... You're doing the opposite of what's best to achieve
a quiet system, using parts that create more heat. Even so, low noise
is an attainable goal. The soluytion is always the same, use large
efficient heatsinks, low RPM quiet fans, and a case that allows and
makes good use of airflow, especially for components more subject to
differences between different cases' airflow, like the hard drives.
Use multiplie lowest RPM fans instead of fewer, higher RPM fans.
Dave