I've just built a small HTPC with the following:

  • APEX MI-008 Black Steel Mini-ITX Tower Computer Case 250W Power Supply
  • AMD A8-3870K Unlocked Llano 3.0GHz Socket FM1 100W Quad-Core Desktop APU (CPU + GPU) with DirectX 11 Graphic AMD Radeon HD 6550D AD3870WNGXBOX
  • CORSAIR 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 Desktop Memory Model CMV4GX3M2A1333C9
  • ASRock A75M-ITX FM1 AMD A75 (Hudson D3) HDMI SATA 6Gb/s USB 3.0 Mini ITX AMD Motherboard

So I realized too late (when assembling) that the CPU heatsink assembly is too large for this case, so I'm running the power supply externally now. What I can't figure out is why when I'm watching the hardware monitor in BIOS (no OS even installed yet), my fan RPM's are at 5k and rising, and my CPU temperature climbed steadily up to 50 deg Celsius ...

This feels wrong. Did I screw up again with the parts above? Should I be checking something? I have the machine off now (been running for only about 10 minutes in it's entire life), and I'm afraid to turn it back on until I have a better idea of what's happening here. Would appreciate any help or advice you could provide!

Pictures for the visually inclined:

And yes, as mentioned before, that is my PSU hangin' out the back there...

  • Pictures, just post one direct shot of the entire inside from the side of the case and any of us can point out what went wrong, question though you said the heatsink was to big for the case, so is it on the processor or not, and if so did you use thermal compound out a copper shiv. – user88311 Jun 28 '13 at 23:16
  • I'm using the stock heatsink/fan (pre-applied thermal paste). I'll see about getting that photo... and yes, the heatsink and fan are installed on the processer, I just moved the PSU to the outside of the case. – neezer Jun 28 '13 at 23:22
  • That would be great. What type of thermal compound, silver based, gold based, ceramic. – user88311 Jun 28 '13 at 23:24
  • Looked silver-based, but the box didn't specify, so I can't say for sure. Again, it's whatever paste AMD would ship it with for this processor. – neezer Jun 28 '13 at 23:29
  • Most likely silver, although it's usually best to get something brand name, I prefer arctic silver 5, how much did you put on, did you just gob some on and place the heatsink on, did you plaster it on thick, like well, plaster, or did you spread a thin film of it accross. – user88311 Jun 28 '13 at 23:34

Even though you have (at the moment) a void in space with the missing PSU, the heated air may not move very well in the tiny case. At some point, you will want the PSU contained in the case (correct?).

An idea that you would want to investigate is adding a fan for circulation similar to this for the same case you listed.

Case fan

The addition of a low profile CPU cooler option will also be required. Here is one example: Xoxide

low pro 1

low pro 2

  • Yeah, I would like to ultimately get the PSU back in the chasis, though I'm worried that I won't be able to find a heatsink with a small enough clearance. That photo above doesn't look like it has a heatsink on the CPU... – neezer Jun 29 '13 at 0:01
  • To that note, would a 120mm fan in this arrangement offer enough airflow if I removed the 40mm fan from the heatsink? That would give me enough clearance to put the PSU back in, though it does significantly hamper airflow... – neezer Jun 29 '13 at 0:07
  • @neezer - the fan is sitting on the outside edge of the mobo. The heat sink is coming nowhere close to that is it? Also, the PSU looks like there would be a slight clearance from the CPU fan if it was installed, correct? Or does the PSU actualy not clear the heatsink/fan? – Carl B Jun 29 '13 at 0:08
  • @neezer - I would not recomend removing a fan from a CPU/heatsink. Those things get too toasty too quick to not have it's own air flow. – Carl B Jun 29 '13 at 0:10
  • The PSU does not clear the heatsink + the fan. It will clear the heatsink alone. The position of the 120mm fan would be appox. 2 inches away from the heatsink. – neezer Jun 29 '13 at 0:10

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