Very hot CPU, no air flow? Please help!

N

nj473

Member
Hi, with help from the guyes here at computer forum, i have managed to build my first PC.

Although I've run into a problem...

I've turned on my computer without a graphics card or HDD a few times (as those parts were in the post) to test if it works. It worked fine with no issues whatsoever. However when I put my graphics card and HDD in, ive noticed that just switching it on seems to be a problem...

The CPU temp keeps rising until about 74C (according to BIOS) and the fans are going crazy... I just dont know why. I never had this problem when the graphics card and HDD were'nt in there, so I think somethings obstructing the airflow. The CPU is installed OK so it shouldnt be anything to do with the thermal compound (also as mentioned, i had no problem until i put the graphics card in).

It looks to me like the graphics card is splitting the airflow, and preventing any flow going above it to the CPU and rear fan.

(*extra note: noticed that when i took the case door off when it was at it's worst, it seems to breathe a sigh of relief i.e. the fans slow down temporarily as if it has had a gasp of air)

I have some pictures of my build to help explain the problem:

Is the airflow doing this?
1-isitdoingthis.jpg


Or is it doing this?
2-orisitdoingthis.jpg


I think the second image looks likely, as i said before it looks to me like its the graphics card that is preventing the flow. (but i am no expert)


Would it help to put a fan in the side of the case facing the CPU? I have labelled potential fan locations as A or B.
3-wouldthishelp.jpg



Another view without the case door...
3-wouldthishelp2.jpg



I am thinking if I put it in position A then the fan would draw air from outside and pump it in, flying past the CPU and then exiting through the rear, making up for the obstructed airflow coming from the front.

Any help would be appreciated as I haven't even installed windows yet for fear of the thing melting or something! I need to know what I can do to avoid these temperatures, and the terrible loundness of the fan when it's struggling.

As i said before, i had none of these problems without the graphics card installed.

Note I am using:
Processor: AMD Phenom II x6 1100T BE
Graphics card: Sapphire Radeon HD 6670 1GB
Motherboard: Asus M5A99X EVO
Case: Coolermaster CM 690 II Lite with 2 stock fans only (one front, one back)

Thanks
 
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you have room for cable management...might want to try that, im not sure if your front section is being blocked off by cables, that could help. also check the TIM on the CPU, as even with low airflow you shouldnt be hitting 73 with the stock HSF on a phenom...somethings wrong there. adding fans would help but i think you have a issue with your thermal compound
 
aw no do you think so?

But remember it doesnt do all that crazy stuff when the graphics card isnt in there, it seems to run normal. (obviously i cannot tell whats going on screen if the graphics card is out though, but it sounds and feels completely fine)

If i do have to resort to applying new compund, how would i do it? is it doable with the motherboard still in the case? I don't want to have to take it all out. And would I have to take the processor off the motherboard to clean it?

Cheers
 
Do some cable management like FuryRosewood pointed out. Did you apply the thermal paste evenly. Check your bios and see if your CPU cooler is running at the same speed it's suppose to. If all fails just get a Noctua CPU Cooler and watch your temps plummet.
 
OK I will at least try to manage the cables better and get them out of the way.

How else would I know whether the thermal compound was applied wrong? I just put the HSF on the CPU as it instructed though I did squash it down and wriggle it a bit when installing. Surely that wouldnt be enough though?

As i mentioned above it seems to gasp for air when i take the case door off and the fan slows down temporarily... what does this mean?
 
The fans will always sound different when the case is on, due to different airflow through the casing. You could always try a better CPU fan, I myself have a Zalman and it works okay
 
I want to avoid things like replacing CPU fan if possible but thanks for the suggestion.

Anyway I've got a little update on the subject, I have been getting these temperatures from the BIOS only, where it keeps rising until it reaches 70 odd degrees. But I have just realised that if I don't go on the BIOS at all, the fans don't go crazy and everything seems fine... Bear in mind as I said I have not installed windows yet so I'm just through to a black screen where the computer isn't doing anything, but it still seems to be a lot cooler.

Is this because the BIOS is demanding? If so does this mean that whenever I do anything demanding then my temps will soar?

Thanks
 
Under no circumstances should the CPU be 74oC in the bios. You have either incorrectly put the thermal paste/heatsink on or haven't attached the fan header to the mobo properly.
 
Think you may be right... even though now I have installed windows 7, on a "balanced" power plan, I'm averaging 26C, and on "high performance" it's about 31C. Take it this is pretty standard?

It's only on the BIOS that it keeps rising, Would it be anything to do with my ASUS TPU switch being enabled? seems as though it's automatically overclocking to what it thinks is the most "stable" state.

Reminder: I'm running a phenom 1100T @ stock 3.3GHZ (though with TPU enabled, it's pushing to 3.75-3.8GHZ)
 
nj473 said:
Think you may be right... even though now I have installed windows 7, on a "balanced" power plan, I'm averaging 26C, and on "high performance" it's about 31C. Take it this is pretty standard?

It's only on the BIOS that it keeps rising, Would it be anything to do with my ASUS TPU switch being enabled? seems as though it's automatically overclocking to what it thinks is the most "stable" state.

Reminder: I'm running a phenom 1100T @ stock 3.3GHZ (though with TPU enabled, it's pushing to 3.75-3.8GHZ)
Click to expand...
Go into your bios settings to do a reset to the default settings and see what happens.
If this fixes your problem then you are OK.
 
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I'm actually at work at the moment unfortunately so I can't access the computer right now. However, I have already tried doing a reset as you have suggested. Problem is, the default settings are the ones causing this. Which is why I ask is it anything to do with TPU?
 
I'm no expert per say. What i would do is clean up the cables, making sure that they are all minimizing the amount room taken (allow for more airflow).

The way i was taught on how to do up the thermal paste is to use Artic Silver (been told it's the best brand for the price). When applying it, put a dab on to the CPU and use a straight piece of some sort of "putty knife" to evenly distribute it around. Do the same thing to the heat sink. This ensures that every millimeter is covered evenly, just be sure you don't apply too much.

I also noticed you only have 40 mm fans. Do you know the CFM rating? maybe those fans don't put out enough airflow of what you need. Just looking at your case, it looks to be a decent size case and with only two 40mm (one inlet and one exhaust) just might not be enough to move enough airflow.

I would first look at these three things if it was me. Then search for other things.



EDIT: I just looked again. I was wrong on the fan sizes, looks to be 40mm inlet and 120mm outlet. Is this correct? It also looks like you can add another 40mm fan to the front. Maybe i am totally out to lunch, but to have decent airflow you want to put in as much as you exhaust.

Before you comment, i know that there are holes and will draw air in, but i was just talking about fan control. I revert back to fire fighting. When exhausting smoke there were three methods, Positive Pressure Ventalation (PPV), Negative Ventalation, and what people call on here the Push Pull method. PPV is efficient yet no air is controlled. Negative makes the fans work harder. And the Push Pull method allows to direct the air where you want it. I personally like the Push Pull method.
 
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Hey thanks for the in depth suggestions.

The fans are 140mm at front dragging air in and a 120mm at the back pushing air out. I have since bought a new 120mm fan in case I need to put it in the side, but for now my computer seems to be stable whilst its in windows. It's just the bios that makes it heat up like crazy, and as someone pointed out before, under no circumstances the CPU should apparently reach 70 something degrees in bios.

These answers have led me to believe now that it is not the airflow, and it is probably the thermal paste being applied wrong even though I was sure I did it right... I just stuck the fan and heat sink with pre applied paste onto the CPU as instructed. I wiggled it about a bit though which Is making me think that may have done something wrong.

The air flow should be right after having a look around now, I have done the suggestion of cable management so now there is very minimal obstruction in front of the fans path.

Still concerned that it may be something to do with the TPU though, can anyone shed some light on this?

Thanks
 
Reset BIOS as suggested, that will rule out your TPU thoughts. Another thing would be to monitor temps with CoreTemp. BIOS tends to read hotter because, there are no power management features for BIOS so its running your system at full power.

So reset BIOS then monitor with CoreTemp (or any other reputable temp monitoring program.)
 
If by default overclocking is enabled then maybe find out how to disable it. If it is only 31 degrees in windows than there is maybe a problem with the temperatures being read improperly, if bios is saying one thing and windows is saying another. Maybe try a program like speedfan.
 
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