The smackdown on the CAK38

[compaq_ML530]

Got my CAK38 from Heatsinkfactory today. Here's my experience.

Prior to installing, I ran Seti@home on my PC for about 6 hours. Took temp measurements with CompuNurse probe. Room temp was 88F/ 32C, Case temp was 89F/31C, CPU Temp was 47C/116F.
The T-Bird 1.2@1370 wouldn't post at 1.8V (it posts with room temp below 85F) so I dropped it back to 1301(9.5x137)@1.8V. The HSF fan being replaced was the Vantec FCE-62540D. It was lapped to a mirror shine and I used Artic Silver II.

After Installing the CAK38 (no lapping, used Artic Silver II), I booted the PC up at [email protected]. After running seti@home for about 2 hours, I checked the CPU temps and they were identical to the Vantec. I was ticked. I then checked the room temp which by this point rose 2 degrees F. As a joke I thought I would try 1370 (10x137) and it posted and booted Win2K. Not only that, but as I'm typing this up, I'm burning a CD, watching ESPN on the WinTV, running Seti@home, checking email, and browsing the internet. Completely stable!! The CPU temps are at 48F/118 solid at full CPU load. It's 90F in here!!!! I went from completely pissed off at wasting $38 to completely shocked. The CAK38 was definately a good buy. I would definately recomend it. I now need to update my signature...lol

 

[Kryten]

Glad to see you having positive results Compaq, I spent a few hours yesterday looking at different HSF combos I like the look of the CAK38 figures, only problem is the weight @ 450g it is a little heavy for what I want to do.... I want to use the HSF until I have a water setup going then I would like to put the HSF on top of the watrerblock.
Still in the process of researching it but I am likely to go with the 6035 Alphas (dual mobo) at the moment they are only 290g or the FOP38 @ 200g.

 

[WillysNut]

Congrats. I'm getting similar results from my CAK. I went from barely being able to run a Gig to running 1037 stable at 2v, 32c load. I agree that this unit is heavy, but it does its job perfectly.

The clip that some call hard to mount, I found very easy to use w/ my finger and a pair of needle nose pliers. The clip apply's in the range of 22ft/lbs. of force. If you plan on moving your computer a lot, I would stay away from a heavy sink...as many have suggested, but once this thing is on...it stays.

Congrats on your OC....I may be heading to "whispering" AMD land soon to try my luck. Why not have both eh???

 

[Kryten]

What I find real interesting here is that although your temps never altered greatly your stabilty did...Are we missing a whole new avenue of thought that needs to be considered?

 

[William]

Kryten (May 15, 2001 07:13 p.m.):
What I find real interesting here is that although your temps never altered greatly your stabilty did...Are we missing a whole new avenue of thought that needs to be considered?

we probably are, nothing I can think of just yet, but its has me thinking, will post if I can think of something. Part of is that copper absorbs heat much better than Aluminum does, but it also would rather keep the heat than letting it out to the air. Hmm, gonna have to get the wheels turning.

 

[jeff_harrison_344]

I am SOOO happy to hear that, cuz I just ordered a CAK38.

So tell me, is the noise really 'that' bad?

 

[Kryten]

dunno260 (May 15, 2001 07:17 p.m.):

Kryten (May 15, 2001 07:13 p.m.):
What I find real interesting here is that although your temps never altered greatly your stabilty did...Are we missing a whole new avenue of thought that needs to be considered?

we probably are, nothing I can think of just yet, but its has me thinking, will post if I can think of something. Part of is that copper absorbs heat much better than Aluminum does, but it also would rather keep the heat than letting it out to the air. Hmm, gonna have to get the wheels turning.

has me thinking about it now too.. maybe the temps are only part of the big picture and not all of the picture, maybe how fast it pulls the temp away from the source might just be as important.

 

[compaq_ML530]

Kryten (May 15, 2001 07:13 p.m.):
What I find real interesting here is that although your temps never altered greatly your stabilty did...Are we missing a whole new avenue of thought that needs to be considered?

This had me scratching my head too, as I can only guess that the copper sink is pulling the heat off the core in a faster fashion. Is there a way to measure the time it takes to dissapate heat from the base to the top of the fins?

Another note, the Vantec aluminum sink never really got "hot" (hot being somewhere between warm and burn your finger). The CAK38 sink is noticably "hot" when the CPU is under 100% load.

Another good thing about this cooler is that the delta fan doesn't seem to be as loud. With the Vantec, you could hear the harmonic vibrations from the sink. Note: I drown the sound with 2 120mmx38mm, 1 92mm, and 3 80mm fans. If the delta was the only fan in the case, it would still be dang loud.

 

[compaq_ML530]

Kryten (May 15, 2001 07:47 p.m.):

dunno260 (May 15, 2001 07:17 p.m.):

Kryten (May 15, 2001 07:13 p.m.):
What I find real interesting here is that although your temps never altered greatly your stabilty did...Are we missing a whole new avenue of thought that needs to be considered?

we probably are, nothing I can think of just yet, but its has me thinking, will post if I can think of something. Part of is that copper absorbs heat much better than Aluminum does, but it also would rather keep the heat than letting it out to the air. Hmm, gonna have to get the wheels turning.

has me thinking about it now too.. maybe the temps are only part of the big picture and not all of the picture, maybe how fast it pulls the temp away from the source might just be as important.

I think the noise is tolerable, but I work in large server rooms with 100's of servers and massive AC units. Have to wear earplugs most of the time to stay sane. I barely notice the noise anymore, the more exposure, the quicker you get used to it.

 

[klosters64a]

Aluminum radiates heat better than copper. Heatsinks lose only an insignificant percentage of their heat via radiation. Heat loss from forced air is essentially the same for both metals.

 

[WillysNut]

I agree w/ Klosters. Copper sinks need to have big fans. My CAK38 def. gets warm to the touch at the base when I run 1053. My big issue right now is w/ Case ventilation.

I have 1 exahust fan and 1 fresh air fan. Neither of which can keep up w/ the CAK38 heat output or the Delta 38 fresh air requirements. Getting a new case today to address the problem.

I'm inclined to believe that Copper heat sinks require a greater degree of case vents than standard alumnium sinks.

 

[compaq_ML530]

WillysNut (May 16, 2001 09:59 a.m.):
I agree w/ Klosters. Copper sinks need to have big fans. My CAK38 def. gets warm to the touch at the base when I run 1053. My big issue right now is w/ Case ventilation.

I have 1 exahust fan and 1 fresh air fan. Neither of which can keep up w/ the CAK38 heat output or the Delta 38 fresh air requirements. Getting a new case today to address the problem.

I'm inclined to believe that Copper heat sinks require a greater degree of case vents than standard alumnium sinks.

Sounds like a good theory. My case temp didn't change after the switch-a-roo because I've got enough air flow...
In a smaller case with little or no air flow, I think that would hurt the effectiveness of the sink.
BTW, If you want to feed the delta with fresh air, just stick a 120x38 103cfm panaflow over it like I did. It won't be hungry anymore.

 

[Kryten]

I know its early days of the CAK but has anyone tried blowing out rather than in, this is what I'm thinking... I will need 2 HSF if I have them both blowing out and a 120mm fan on the side blowing out (obviously other fans blowing in) I could get rid of the bulk of the heat before it has chance to heat up the tower too much.... what do you think?

 

[WillysNut]

I haven't tried it yet...considering it...but if you think about copper vs. alumnium, I'm guessing that you'll get less than desirable results.

I think copper, considering the fact that it picks up heat quicker...but...retains it longer, needs forced air. The fins in a copper heat sink become crucial as the base...as I've felt...usually retains heat more than alum.

The plan I have is to add an 80cm fan on the side panel of my case just in line w/ the inlet of the Delta to bring nice..cool..fresh air thru the delta to the CAK base. The new fan will also help cool the HDD and CDROM.

...just gotta get the dremel outta my dad's hands

 

[Kryten]

hmmmm yeah I see where your comming from but if I have enough air comming in from other sources it may have enough cross flow to take the heat away... guess there's only one way to find out...

 

[Thelemac]

I'm going to assume that klosters64a is correct, as I don't know the actual physics of cooling or thermal transfer or anything, and he is the only one that brought facts into play here.

He says that aluminum and copper lose heat equally quickly with forced air...the cu doesn't keep it any longer than the al.

The cu will, however, feel hotter to the touch with the same amount of forced air because it picks the heat up more quickly, and will spread throughout the structure more quickly than al. Just wanted to straighten that out.

There may be benefits to getting more air across the cu heatsinks than the al....but I think it might be easier to have Joe test it with his "Extreme" fan to help decide if there could be some benefit to doing so (with diminishing returns being what they are and all)

Of course, improved case ventilation will alway help (until you get it too room temperature, of course) cause then you will have a lower base temp than before.