CPU Temperature Question

[Evtrai]

I'm not sure if this the correct board since I'm doubting if the problem is CPU or Video Card, I have a problem, which I can't seem to identify what could it be, my upper video card always seem to have high temperature issues, they go as the following:

First slot: Iddle 63Cº Load 73-76Cº
Second slot: Iddle 42Cº Load 54Cº

My processor temperature: Iddle 46º Load 59-61º (it goes jet speed really loud)

Neither the CPU or GPU are overclocked.

The video cards with the stock coolers they had before, I noticed the first card was always the hottest.

I never checked the CPU temperature with the GPU stock cooler since the sound was camuflaged with both video cards turbo engine.

My computer specs:

2x Radeon HD4870 1GB (Both using aftermarket cooler since they were noisy "Scythe MUSASHI Copper Heatpipe")
Corsair DHX 4 GB (2 X 2 GB) 240-PIN DDR2 800 MHz Dual-Channel
Cooler Master Real Power Pro Series 850W ATX12V / EPS12V SLI Certified CrossFire Ready 80 PLUS
GIGABYTE GA-MA790GP-UD4H Socket AM2+/ AMD 790GX/ DDR2-1200/ A&V&GbE/ ATX Motherboard
AMD HDX920XCGIBOX Phenom II X4 920 2.8GHz Cache 8MB AM2+ 125W Processor (Using stock cooler)

Now my issue is, at first I thought I might have one of the cards with a dud cooler or it was bad installed, redid it but the problem persisted, and to my surprise both cards get the same temperatures as long as they are on the first slot (the second one is always running cool on both cards as long as they are on the second slot), I tried replacing the case with one with better airflow which I thought it might be the problem, fairly larger than the previous one I had, better airflow (2 side fans, one large front fan and 2 back fans. The cables are hidden on the back of the case so there's literally no cable mess on the case, and the result had no improvement on the temperatures

Now my question is, could it be posible that the video card is absorbing the CPU heat? I'm using the AMD stock cooler, would replacing it with a aftermarket cooler such as Scythe KATANA 3 SCKTN-3000 drop both the CPU temperature and video card temperature or any other aftermarket CPU cooler?

 

[ahnilated]

Usually the reason this happens is the air flow between the 2 video cards is bad. You need to make more space between them so they can get better air flow for cooling.

 

[Evtrai]

Is that posible? isn't the space between them standard? since the crossfire strips lenght fits perfectly

 

[ahnilated]

Well you are reducing the air into the first card by having the second card close to it. Try removing the second card and watch the first cards temps drop or move the second card to the 3rd PCIE slot.

 

[Evtrai]

They only seem to have dropped 2Cº

 

[WR2]

I don't think your CPU would be bleeding off heat to be able to make the larger difference in temps you've noticed.

What temps do you get when you run a single card in the 2nd slot by itself?

I think the culprit might be that Northbridge/Mosfet heat sink next to the PCI-e slot.
Can you set up one of your case fans (maybe dismounted from the case) to blow some air across that heatsink and take some more measurements? You might have a 'dead spot' in your air circulation pattern in that area. If you find that reduces the temps you can look for some of those small 'spot fans' and use it to move some air over and around that heatsink.

 

[Evtrai]

You are totally right, I touched it after I turned my PC off and it was incredibly hot, I did the test you mentioned and yes, I measured the air near the heat sink of the motherboard where the video card sits on and it was incredibly hot at 79 Cº are there any especific name for those small fans?

I remember seeing one that was sitting on a heatsink when sometime ago I was looking at CPU cooler and noticed indirectly one that clipped on on the mobo heat sink

similar to that one, only the fan though

 

[Evtrai]

Best answer selected by Evtrai.

 

[WR2]

Here is an example of a spot fan

There are also 40mm chipset fans which look like they would get the job done.

 

[WR2]

It looks like there is a NB fan header just between the PCI-e x1 and PCI-e x16 slots just to the left in that picture above.

I like the specs of that Scythe mini-kaze 40mm fan. You'd probably need some flexible wire to tie it to the heatsink.

 

[Evtrai]

Thanks, all really helped me a lot, I placed a fan on the area temporary and it actually seemed to even help my processor temperatures as now underload max hits 51 Cº and iddle at 43 Cº, as for my video card it dropped to 68 Cº underload, but I'm still seeing the point that Anihilate made as I measured the space between the cards and it's 1cm and 28mm which barely gets any air, so I'm planning of getting two spot fans and place them on a similar matter.

Pointing at the heat pipe and to the fan in the back so it pushed the hot air out.

Pointing to the middle of the cards


Really really thanks a lot, this helped me trough as I was getting worried the max temperature of the CPU is 63Cº and it was almost reaching that, and also hopefully it will help the video card. I'm getting those two spot fans tomorrow.