Q6600 won't use all 4 cores at 100%

[spdfreak]

Here is the scenario- I use this system for video encoding with autoMKV to transcode HDTV mpeg2 files to x264. For a long time, it would always use all 4 cores at 100% while it was encoding, but in the last few days, it will only use about 40-50% cpu. It still uses all 4 cores, but usually in the 40% range. There are no setting in autoMKV to tell it to use certain cores or priority, so I'm wondering what else could be slowing it down. It will run all 4 cores at 100% during benchmarks so the cpu itself is not the problem. Any ideas?
System-
MSI P6N SLI FI 650I MB
Q6600 @ 9x333 3.0GHz
2 GB 6400 RAM
2 HDD

 

[VirtualLarry]

Sounds like you are I/O bound then. The CPU isn't getting enough work to do, because it's waiting on some other part of your system.

 

[GundamF91]

How fast are your HDD? Like VirtualLarry said, it's probably I/O limitation.

 

[Idontcare]

Originally posted by: GundamF91
How fast are your HDD? Like VirtualLarry said, it's probably I/O limitation.

I agree, sounds like (1) your drive is getting fragmented (time to defrag), and/or (2) your drive is getting full'ish (>50%) and now the files are being read/written to those slower tracks on the platters.

 

[spdfreak]

The C drive is a Western digital 400G 7200rpm SATA drive. It is about 1/2 full. Just defragged. I also tried saving the output file to the secondary drive which is a WD 300G IDE drive. Same result. Last week it was using all 4 cores at 100% fine, so something has changed drastically since then. I can run some I/O benchmarks and see what they come up with. Any suggestions? Sandra shows that it is 57MB/sec read and the graph shows that it is just slightly slower than a 500GB WD or 250G Seagate.

 

[Idontcare]

You may have a DPC latency issue.

http://www.thesycon.de/deu/latency_check.shtml

Download the program and see what your DPC situation is like.

 

[spdfreak]

Thanks for all the reply's... I did the simplest thing I could. Deleted all the autoMKV stuff, re-downloaded it and gave it a try. Works perfect now. So I don't know if there is a bug in the autoMKV app or if I messed up some setting, without knowing it. I compared all the setting between the old and new GUI and they are the same, but that doesn't mean something didn't happen deeper than that. I will keep my eye on it and see if the problem returns in a few days.

 

[Lonyo]

Maybe it got set to only run 2 threads instead of 4 or something? That's about all I can think of (4 cores at 50% implies 2 threads running instead of 4, and Windows switching the threads between cores).
That would explain why redownloading fixed it if it reset all the settings.

 

[spdfreak]

No, it was using all 4 cores, just not at 100%. Plus, you can go in and set the # of threads to whatever you want. I have a feeling it is a software bug, but I'll have to wait and see if it repeats.