Cooling strategy for your AMD C'n'Q CPU ?

[Thomas]

I'm looking for inspiration for cooling my upcoming Athlon approx. 3800+ X2.

This will be in a P180 with 2 undervolted Nexus' (5-6 volt), and most likely with a VGA card in the 40-50 watt range. The VGA will be passively cooled (plan B is a VF-900 with fan mod).

I dont want to fiddle around with CPU undervolting etc., so I'll simply use Cool and Quiet.

I havent decided on mobo or CPU cooler yet.

I would prefer a nice CPU HSF with a fan at low RPM (5 volt or so), and where the mobo will spin the fan faster if needed.

So I would simply like to hear what other people do...

Thanks,
Thomas

Edit: There will be no overclocking.

[Steve_Y]

At stock speeds I'd have thought a large cooler like a Scythe Ninja could passively cool that easily.

I know you said that you don't want to mess around with undervolting, but you might want to have a look at CrystalCPUID. It allows easy undervolting from the Windows desktop and in my opinion is worth the effort.

[Lawrence Lee]

I use a Scythe Mine (Ninja wasn't available at the time) with a Coolermaster 120mm fan to cool an dual-core Opteron 165 at 2.5Ghz (1.6Ghz/0.90V idle using CrystalCPUID) . The fan is connected to the CPU fan header which I control in Windows with Speedfan. I've configured it to run at 35% speed until the CPU hits 40C, then it begins to ramp up, to a maximum possible speed of 80% ~1000RPM). The same goes for my PSU and video card fan. The DFI NF4 Ultra-D has 3 controllable fan headers. Idle, my suspended hard drives are the loudest thing in my case. On load, all I hear is a gentle whoosh.

[Thomas]

Amourek: I've considered SpeedFan, but I dont like the idea of having software controlled fans. Simply because I dont believe in software stability, when there's heatproblems. Thanks for your input anyway.

Steve_Y: AS far as I've understood undervolting, then I have to sacrifice the auto-throttling that C'n'Q provides.

As far as I understand, then it's needed to lower both voltage and frequency to obtain the lowest possible powerconsumption, which translates into less heat.

I dont want to manually switch to high frequency, when I need full power.

Is such a CPU able to run full speed, while undervolted? But then again, if I only undervolt, and dont underclock, will I gain much compared to C'n'Q?

The processor I'm looking at, is a 65 watt TDP.

I tend to get a Ninja, and trying running passively, except for the case fans, of course. But I'm somewhat concerned about when my CPU will run at max load for several hours. Have some of you guys tried that?

Thanks.


Thomas

[Steve_Y]

Steve_Y: AS far as I've understood undervolting, then I have to sacrifice the auto-throttling that C'n'Q provides.

CrystalCPUID has its own equivalent of C&Q; you can set a different multiplier and voltage for different levels of CPU load.

There's an article about it here at SPCR: http://www.silentpcreview.com/article231-page1.html

I've found that the middle state isn't very useful and only use the minimum and maximum, but that could be because of the particular way I'm using my PC. Generally I'm either running at a very light load (web browsing, downloading, office tasks, etc.), or I'm playing a game or encoding audio and it's constantly near full load. Having it just switch between 1Ghz @0.825v, and 2Ghz @1.025v, keeps things simple and seems to work well.

Is such a CPU able to run full speed, while undervolted? But then again, if I only undervolt, and dont underclock, will I gain much compared to C'n'Q?

From what I've heard, and from my own experience, you can almost always undervolt lower end X2s while running them at their stock speed. I'd expect that CPU to undervolt down to around 1v without any underclocking required. When idle and underclocked you could have it running at 0.8v, which seems to be as low as the X2 goes.

Using CrystalCPUID's multiplier management rather than C&Q saves me around 10W at idle and 20W under load. Quite significant considering that my X2 3600+ isn't particularly power hungry to begin with.

I tend to get a Ninja, and trying running passively, except for the case fans, of course. But I'm somewhat concerned about when my CPU will run at max load for several hours. Have some of you guys tried that?

I've tested my X2 3600+ @ 2Ghz running two instances of Prime 95 to fully load the CPU. Even without undervolting, the Ninja could easily cool it without too much airflow (1 92mm Nexus and 1 120mm 1200RPM Scythe S-Flex, both running at around 7v), undervolted I haven't seen CPU temperature exceed 40C. Quietly cooling a low end X2 is trivial for a large and efficiently designed cooler like the Ninja.[/url]

[Thomas]

Steve_Y: Okay, that's it: I'll aim for passive, and probably also some undervolting.

My way of using my PC, sounds quite similar to yours, either light or gaming/video encoding

I believe it'll require a mobo, which support undervolting?

Thanks man !

[Thomas]

CrystalCPUID has its own equivalent of C&Q; you can set a different multiplier and voltage for different levels of CPU load.

There's an article about it here at SPCR: http://www.silentpcreview.com/article231-page1.html

I'll dig into this. Thanks.

[Thomas]

Been through the CrystalCPUID article a few times. Dont looks that difficult

Thanks again, also to all who voted

[Max Slowik]

Also, Cool'N'Quiet doesn't necessarily work with Vista; it does only if the motherboard's BIOS has the firmware to pull it off.

But CrystalCPUID /does/ work with Vista x64, (it, in theory would require some tweaking to work with x32) which makes it that much more appealing.

[Techno Pride]

I'm using RMClock for my X2-3600+ (Windsor 90nm)

Idle 1GHz/0.9v
Load 2GHz/1.075v

Passive Ninja, ducted to rear Yate Loon D12SL-12 @ 6v.