Very high CPU temp when encoding with x264

[eXtremeDevil]

Hi, sorry if this is the wrong section but since I think this is a x264 error I'm posting here.

I have always used DGAVCDecNV (DGIndexNV) for indexing my avc recordings for later encoding. For the encoding, I use MeGUI and a custom setting in x264 command line options:

--opencl --opencl-device 1

I have been working like that for some time now. As far a I know, I'm using my Nvidia card to do all the work.

I had to format my Windows recently, and today, when I started a new encoding, I found my CPU temp going to 100 Cº.

It looks like the CPU is doing the job rather than the GPU, right?

I tried to run the job with x264 CLI but it gave me an error about an Avisynth plugin not found, why is that?

Thanks in advance.

[sneaker_ger]

x264 encoding is mostly done on the CPU even with open-cl enabled. If your CPU temp reaches 100°C it would point to inadequate cooling.

Originally Posted by eXtremeDevil

I tried to run the job with x264 CLI but it gave me an error about an Avisynth plugin not found, why is that?

1. The plugin is missing from your system
2. You have only 32 bit/64 bit version of the plugin installed but your software is opening AviSynth 64 bit/32 bit.
3. The plugin is missing a dependency

In the future post all logs/error messages/scripts as well as the hardware info.

[eXtremeDevil]

OK, I'll try those fixes, but what about the temperature?

EDIT

CLI works now, thanks for that! But CPU temp still goes up with that method...

[sneaker_ger]

Fix your cooling/hardware. It's not an x264 problem.

[eXtremeDevil]

No, what I mean is, if idle my CPU is on 40-50º, but when enconding it goes up to 100º. It is weird, even more if I'm using my GPU not my CPU to encode, right?

Maybe an OpenCL device issue? I tried 1 and 2 and the results were the same...

[sneaker_ger]

Like I said: even with opencl enabled most of the work x264 does is done on the CPU. Only a small part is handed to the GPU. So it is totally normal for CPU temperature to increase. If your CPU hits 100°C it means your cooling isn't working as it should. It could be inadequately designed (cheap laptop), the heat paste not applied correctly, the fan is broken/not attached, too much dust, or you have too much overclocking.

Originally Posted by eXtremeDevil

Maybe an OpenCL device issue? I tried 1 and 2 and the results were the same...

You still haven't posted any logs at all. No one here could tell if OpenCL is working in the first place. Either way your CPU shouldn't hit 100°C.

[eXtremeDevil]

I will clean my cooler and post back, thanks.

[eXtremeDevil]

As I suspected, the cooler was almost clean. The thermic paste was dry, though. I changed it and cleaned the cooler anyway. Now the temp is 80~ when encoding. Is it normal? I just started, it may go up to 100 again... also, the temp here in my city is 35 right now.

Are those normal values? May the temp lecture be wrong?

[sneaker_ger]

35°C ambient temp is certainly high. Depending on your hardware - which you still haven't told us anything about - 80°C might be perfectly normal.

[eXtremeDevil]

I have an i7 4790K and a MSI Gaming 3 Z97 motherboard. Also, Nvidia GTX 970. Cores are swinging from 79 to 88 now...

EDIT

Looks like it is oscillating between 80 and 90 for a while now.

[sneaker_ger]

I'd say it's still a barely acceptable temp. Not good but also not alarming. Maybe the heat paste still isn't applied optimally or it's of low quality? Are you using the stock cooler? How hot does it get if you use x265?

[eXtremeDevil]

Funny, if I add '--threads 4' to the cli command, the temp is 15º~ lower. My CPU has 4 threads right? or is it 8? In any case, the time of the encode is the same.

EDIT

Never mind, I do have 8 threads, and with 4 the time is a bit more.

[sneaker_ger]

i7-4790K has 4 physical cores + 4 virtual ones (hyperthreading). x264 can be up to 20% faster with hyperthreading. If you get exactly the same fps with --threads 4 (instead of default [sum of physical+virtual cores] * 1.5) you may be bottlenecked somehow. Compare CPU utilization in task manager in addition to fps difference. (Again: you haven't really posted anything about the source, script or settings.)

Indeed, without using hyperthreading/with less threads the temps should be lower. So that's expected.

[eXtremeDevil]

Settings:

--preset veryslow --crf 18.5 --deblock -1:0 --keyint 25 --min-keyint 13 --ref 9 --no-dct-decimate --no-fast-pskip --opencl --opencl-device 1

Script:

DGSource("G:\SNL\43x07.dgi", crop_t=0,crop_b=0,crop_l=4,crop_r=4,resize_w=1280,resize_h=720,deinterlace=1)

Source:

Video
ID                                       : 101 (0x65)
Menu ID                                  : 4034 (0xFC2)
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L4
Format settings                          : CABAC / 4 Ref Frames
Format settings, CABAC                   : Yes
Format settings, RefFrames               : 4 frames
Codec ID                                 : 27
Duration                                 : 41 min 46 s
Bit rate                                 : 5 947 kb/s
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 25.000 FPS
Standard                                 : Component
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : MBAFF
Scan type, store method                  : Separated fields
Scan order                               : Top Field First
Bits/(Pixel*Frame)                       : 0.115
Stream size                              : 1.74 GiB (92%)
Color range                              : Limited
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709

[Blue_MiSfit]

x264 will push your CPU for sure. It's not the software's fault - x264 is widely used across the broadcast / streaming industry for H.264 encoding on many tens of thousands of servers all over the world.

Sounds like your cooler is not up to the task. However, Intel CPUs can take the heat. My i7-7700k gets HOT when encoding, even with a small all-in-one watercooler at stock speeds. It doesn't throttle until near 100c.

What cooler are you using?

[eXtremeDevil]

Raijintek Themis CPU Cooler (Product number: 0P105255)

https://www.raijintek.com/en/product...hp?ProductID=3

[Blue_MiSfit]

Looks a bit sketchy to me, no mention of thermal dissipation capabilities on the spec sheet...

Maybe your fan isn't moving enough air
Maybe ambient air temperature is high
Maybe the fins are dirty
Maybe there's not enough airflow in the rest of your case

There could be any number of issues.

Either way, x264 is definitely not the problem.

[eXtremeDevil]

OK, thanks!

[AMED]

Maybe have a quick look at your CPU fan profile in your BIOS. You may need to set the desired CPU temp lower so the fan speeds up a little earlier.

[eXtremeDevil]

I'll try that, thanks!