On Thursday, 16 May 2024 11:13:31 BST Frank Steinmetzger wrote:
> Am Wed, May 15, 2024 at 07:08:11PM +0100 schrieb Michael:
> > Hi Alan,
> > 
> > On Wednesday, 15 May 2024 15:23:47 BST Alan Mackenzie wrote:
> > > Hello, Gentoo.
> > > […]
> > > So I'm looking at getting an AMD Ryzen 7 7700X processor, and using its
> > > inbuilt graphics rather than buying a distinct graphics card.
> > 
> > […]
> > 
> > > As a somewhat tangential question, would it be worthwhile getting water
> > > cooling in my new machine?  In particular, to reduce the noise it gives
> > > off while building large packages such as clang and rust?  Or is water
> > > cooling only sensible for really heavy users such as gamers?
> > > 
> > > Thanks for the upcoming answers!
> > 
> > WC will be quieter and more expensive than an after market air cooler.
> 
> Are you sure about the noise? First there is the water pump and second,
> the heat from the air cycle needs to get somewhere, which is donw with fans.
> So unless you get a big radiator with several fans, you just relocate the
> fan noise inside the case.

Unless faulty a WC pump is inaudible.  A radiator with two 140mm fans will 
just tick over, even under heavy load and overclocked, while I've see AC fans 
spin above 1200 RPM.  Either way, I think there's more noise coming out of 
case fans than the CPU's AC, which is in the guts of the case.

Another way to think about it, the liquid cooling medium can absorb more heat 
until it is saturated enough to start spinning higher the 2 or 3 radiator 
fans, which are typically larger than AC fan(s).

There's also a question of just buying an AIO cooler, or some custom oversized 
build which will be on a different level of performance (and cost).


> I have a 10 years old i5 with a TDP of I think 84 W. On that sits a normal
> (not even high-performance) tower cooler with a single 120 mm fan. At full
> load the CPU draws around 50 W, maybe even less unless you do prime95. So my
> cooler is basically overkill. But this allows the fan to never leave the
> minimum RPM range of ~500…600 1/min and is unaudible even at full load.

Yes, at these RPMs it will be very quiet, but I expect your new CPU will spin 
its AC faster when under load.


> However …
> 
> > You could invest the money toward more RAM, (more/bigger) case fans, a
> > better PSU, monitor, speakers, a new car, etc.  :-)
> > 
> > https://www.techreviewer.com/tech-specs/amd-7700x-tdp/
> > 
> > Cranking up 16 threads to 5.4 GHz will produce some heat, but compiles
> > will
> > complete sooner too.
> 
> … the 7000X are hotheads, because they operate way above the efficiency
> sweetspot just to get the longest bar in benchmark diagrams. If you reduce
> the power target¹ in the BIOS, you lose a few percent in performance, but
> get a disproportionately bigger reduction in energy consumption.
> 
> ¹ The TDP of a 7700X is 105 W. The maximum permanent power draw is TDP * 1.4
> (ish, can’t remember the exact details right now). So if you reduce the
> target to 84 W, you draw a little over 100 W. That’s easy-peasy for a
> mormal 120 mm tower cooler. One additional advantage of an air cooler is
> that it also blows air over your mainboard and its power stages. That’s
> something you don’t get with a water loop and need an extra case fan for—IF
> you keep the CPU on high load all the time which causes more heat buildup
> in the VRMs.

As you say, an AC can also draw air at close proximity over the RAM modules 
and VRMs compared to the more diffused airflow of case fan(s), which is an 
additional benefit.  If you will tune down the CPU, as opposed to O/C it, then 
I think an air cooler will be more than adequate and represent more bang for 
your buck.

I came across this video, but more detailed reviews and tests should be 
available for your specific CPU in the interwebs:

https://www.youtube.com/watch?v=lxf4ZXJTNpI