What am I doing wrong? Help?

[b4417]

I cannot seem to get the temperatures down on my rig. CPU temps hover around 55C under load, and about 45 idle. Case temps stay around 43C. System specs: Lian Li PC-75 (Full tower) case with two 80 mm fans bottom front (blowing in), two 80 mm fans vertically mounted on the back panel behind the Mobo (blowing out), and two 80 mm fans on the back panel (above the PSU) blowing out (plus one 70mm fan blowig on the hard drive, but only using inside-case air). All the fans are on Nexus controllers, so I've worked to balance the speed to get good pass-through airflow -- ie: the front two fans are running at slightly twice the speed of the four back fans (to make up for the difference added by the PSU fan). But I obviously ain't gettin' it right. I've tried half a dozen different heat sinks for the processor (Intel 3.06, not overclocked), and come up with differences amounting to only about 5 degrees C. Using Arctic Silver 3 as paste.

The CPU temps may be a little off, as they're coming off the Intel (D845PEBT2) MoBo sensors which are likely not very accurate, but the case temps are pretty reliable as I'm using Lian Li front-mount temp gauges for that, and the sensors are accurate (within a couple degrees at least).

Any suggestions or advice?

Thanks in advance,
Bill
:brokenheart:

 

[BG4533]

It seems to be your case temps that are the problem rather than your heatsink. Your heatsink is doing a quite good job cooling that power hungry processor as it is only 2c hotter than the case. Do your case temps drop with your fans all the way up? Make sure you have all of your cables out of the way of the airflow and no other restrictions between your intake and exhaust fans. Other than that, I dont know what to say.

Brian

 

[deerslayer]

I agree with BG4533. Your CPU temps are directly related to your case temps. If you can bring the case temps down, most likely your CPU temps will come down as well.

Like BG4533 said, make sure all of your cables are out of the way so the air isn't being restricted. What kind of fans are you using? Did I miss that in the post?

 

[b4417]

The cabling inside is pretty neat -- I have all rounded cables (IOSS shielded), and with the side window exposing everything, I've tried to keep stuff pretty orderly both aesthetically and functionally. Turning all the fans wide open helps by a few degrees at most, but the noise gets too bothersome (the front 2 fans are running almost wide-open even now). All the 80mm fans are Kingwin Tri-lights -- pretty decent CFM from them compared to all but the super-high CFM (and way noisy) fans like the Vantec Tornado and Sunon mega-blaster.

One thought I had last night -- maybe I'm getting some turbulence inside there that's screwing up the airflow? I'll try some more fan adjustments and see what happens. You'd think that someone that's been in the ventilation business for 15 years could figure this out -- guess there's a slight difference between the mega-thousand CFM's in wide-open spaces I deal with at work and the few hundred in a closed computer case.

Anyway, thanks very much for your thoughts and help.

Bill

 

[pelikan]

There has got to be something fishy going on there there. With your set up case temps should be within 5C of ambient.
A simple test you can use along the way while optimizing air flow is to take the side panel off your case and see if temps go down. With good air flow temps should not fall more than a few degrees with the side panel off. With very good air flow temps will rise with the side panel off.

 

[Ness]

About 3 weeks ago, I updated my BIOS, and to my surprise, my temps went down about 8-9 degrees. I suppose there were errors in calculating the temps and the new BIOS fixed the problem. So while I was worrying about my temps getting high, they were actually quite lower than what was reported.

You could try updating your BIOS and seeing if there isn't a problem, or grabbing a thermometer and checking what it says your case temps are to see if your software is being truthful.

 

[mechBgon]

Yeah, what ness1469 said. Do a reality check with a thermometer, if you've been getting your temps from monitoring software. Radio Shack sells indoor/outdoor digital thermometers for about $15.

Also consider porting the Lian Li's exhaust grilles so the fans don't have to try to cram the air through those little slots... this will probably approximately double your exhaust flow, and reduce noise too.

 

[b4417]

Thanks, all. I did manage to get things down quite a bit overall this weekend by monkeying with the airflow (ie: fan speeds). Case temps *did* drop with the side panel off, so that advice helped me figure out for sure that my airflow inside was screwed up. I ported the fan grills when I first got the case, and replaced them with some small wire grilles. So at least I didn't have to disassemble everything to do that (but still damn good advice). Surprisngly, what helped most was turning *down* the speed of the front fans.

So, I'm comfortable now with what I've got -- about 38 C inside the case, and 43C on the processor (idle, about 49C under load). Anybody think that's still too high?

Many thanks for all the help,
Bill

 

[Ness]

That will suffice. Most processors can run safe in the high 60's, Athlon XPs will run into the high 70's... so right now you are sitting in a good spot. It would stll be worth it to make sure that is right, because people get better temps having half as many fans or less. But again, right now you are in a good position so there really isn't anything to worry about.

 

[BG4533]

A bit, but I dont think it is something to worry about very much. Is your room warm?

Brian

 

[pelikan]

b4417- It is very interesting that turning down the front fans helped reduce temps. I have been similiarly suprised with certain fan arrangements working better than others, especially with my cpu duct. Since I never seem to know exactly what to expect I just try everything I can think of until I find the best set up.

 

[deerslayer]

Those temps are fine

 

[b4417]

Thanks all. I think I'll leave things be, and do something improtant with the rig now, like play games. To BG4533, my room is fairly warm at 80 degrees F, due to the spousal unit being very cold-natured and unable to deal with low-70's temps like I prefer. Marriage is a compromise, or so they say. Anyway, thanks to all who pitched in and offered help. Much appreciated.

Bill

 

[huesmann]

OMG I could not survive at 80ºF!

 

[b4417]

Originally posted by: huesmann
OMG I could not survive at 80ºF!

Haha!! Me either, hardly. That's why I normally run around the house in my underwear. Strangely enough, the wife doesn't seem to mind that. Or perhaps she just accepts it in order to keep the house in oven-like conditions?

Bill