Is my video card causing wrong cpu temp reading?

**ylen13** · October 24th, 2009, 09:08 PM

At normal idle temp my system is running around 50c, that is using intel stock cpu fan and 3 120 case fans. Case fan temp is around 51 at all times

When running my cpu at 100% temp will hit 100c. The heat sink is warm to the touch and not hot as would be expected at that high of temp. So am i getting wrong reading or for some reason my video card is causing the temp to show hotter than it's really is as 4870x2 runs super hot? Also I can't hear cpu fan really speeding up like I can when system first starts. So what could be going on?

Specs I7 920(not oc), ati 4870x2(not oc), 6gb pc 1600 ram. Asus p6t delux v2, COOLER MASTER RC-690-KKN1 mid tower case, 2-1tb had drive edit:Running win 7

**Train** · October 24th, 2009, 09:32 PM

Sounds like a air pocket between the cpu and the hsf.

Remove hsf, clean things up with 90+% alcohol.
Apply new thermal paste, paper thin, and carefully reassemble .

**ylen13** · October 24th, 2009, 09:37 PM

Originally Posted by Train

Sounds like a air pocket between the cpu and the hsf.

Remove hsf, clean things up with 90+% alcohol.
Apply new thermal paste, paper thin, and carefully reassemble .

Interesting, didn't think of that. The only thing that confused me is cpu do not clock down and also it do not shutdown by it self as would be result with overheating.

**Train** · October 24th, 2009, 09:40 PM

Generally that air pocket is a real hair puller.

If the above does not fix it, then my thoughts lean toward a bad sensor.

**Midknyte** · October 24th, 2009, 10:14 PM

3 120 case fans. Case fan temp is around 51 at all times

51C in the case? How many of your fans are intake/exhaust? You need to have more exhaust to get the hot air out of the case.

**ylen13** · October 24th, 2009, 10:44 PM

Originally Posted by Midknyte

51C in the case? How many of your fans are intake/exhaust? You need to have more exhaust to get the hot air out of the case.

2 and 2. Well power fan is exhaust, the one on front is blowing in, the on the at the side is blowing in and one at the side at the top is exhaust. Considering i got 2 very hot components in the system to me around 50c is fine.

**Train** · October 25th, 2009, 02:07 AM

Test the side panel fan, some times blowing in is cooler than blowing out, but I have found through experimenting 50% of the time blowing out is cooler.

You should also have a exhaust fan, high in the rear near the power supply blowing out too.
I tend to agree, 50C is to high and you do not have the airflow needed to get the heated air out of the case.

**Midknyte** · October 25th, 2009, 02:12 AM

You don't count the PSU fan, since that is to cool the PSU not the case.

In general it is better to have more exhaust fans than intake (negative pressure). Air will find it's way into the case; you don't need to force it in.

**ylen13** · October 25th, 2009, 01:15 PM

Okay will give it a try. Will have front fan blowing in and have 2 side fan as exhaust fans. I might have room for one more fan...need to open the case to make sure. Will post back in couple of days.

**ylen13** · October 25th, 2009, 06:41 PM

Looks like to me that cpu fan sencor is not working properly. I changed my front fan to blow in, left my side fan as exhaust(i was wrong that they were 1 in and out, they are both exhaust) and my rear fan is exhaust. I am running prime95 and max temp i am getting is 85 for cpu and board is running at 54. The strangest part is cpu fan is only at 2008 rpm. So basically cpu fan is not going full speed like it would if it the cpu was overheating.

**Train** · October 25th, 2009, 06:52 PM

100c to 85C is a nice change.

Rotate both side fans and see what the difference is.

**ylen13** · October 25th, 2009, 10:05 PM

Originally Posted by Train

100c to 85C is a nice change.

Rotate both side fans and see what the difference is.

I added 2 more fans at the top. Decided to put one as air in take and one as exhaust, it was pain to put them in now that i have system all build up. Note to those that planing on using cooler master case, make sure to add top fans first before you start building your computer, it will make your job much easier. Note to cooler master, design the top better.

Anyway cpu temp is around 82-84 with prime 95 running everything at 100 and case it telling is 58. I am still thinking sensor is wrong and temps likely 60-64c for cpu and around 45 or so for the case.

In couple of days i will try you suggestion on rotating the fans and see what will happen with the temp. For now i am just to tired to do it today

Edit:How is it possible that my cpu temp is near idle is now 34c add case fan is 55c. 20c difference and 3c difference between idle and cpu at 100%, maybe it's just me but sounds like i am getting totally wrong readings.

**Train** · October 26th, 2009, 12:25 AM

Time to take a break.

Humm. the case fan is breaking the air flow through the case.

**ylen13** · October 26th, 2009, 12:30 AM

Originally Posted by Train

Time to take a break.

Humm. the case fan is breaking the air flow through the case.

Ye going to walk away from it for couple of days.Current temp cpu is 45 mb is 56, fan 1 and 2 are both at 1016- 1028 rpm, cpu fan is at 2008-2057 rpm

Basically i have this set up

top fans 1 blowing in, and 1 blowing out(pain to switch, can control speed of one of the fans, low to high)

side fans 2 exhaust fans, pretty easy to switch them around, can control speed of one of the fans low to high

fornt blowing in,

back, exhaust fan, can control speed from low to high

**Train** · October 26th, 2009, 12:37 AM

top - out
rear - out
front - in

side - experiment

Anything blocking the air behind the front bezel?

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