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Processor upgrade made transcode slower?

Joe & NicoleJoe & Nicole Members, Plex Pass Posts: 4 Plex Pass

After moving to Plex + Roku's from having htpc's around the house, I noticed some problems with some videos and figured my Celeron G530 just wasn't up to task.

I just received a Xeon E3-1275 V2 (which is the fastest processor available for my mobo), and it appears to be running great except in my one before and after test, it appears to transcode slower?

The new CPU does support hardware assisted transcode, but regardless if I enable or disable it, I don't seem to get the speed I got in my "before" test video which transcoded at ~16x before and only ~7x now.

I am stumped about what the problem could be. There is no way that the g530 was faster than the new processor.

Here is my system in a nutshell:
https://www.asrock.com/mb/Intel/B75M/index.asp#Specification
https://www.cpubenchmark.net/cpu.php?cpu=Intel+Xeon+E3-1275+V2+@+3.50GHz
8GB of DDR3-1600 ram
And a ton of storage.

Any thoughts?

Answers

  • ChuckPAChuckPA Members, Plex Pass, Plex Ninja, Plex Team Member Posts: 22,850 Plex Team Member

    Specs and subjectively saying "appears to transcode slower' doesn't give enough to go on.

    What can you show definitively ? Perhaps playback something requiring transcoding, let it run a 1-2 minutes (DEBUG logging only) and then collect the log files?

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  • Joe & NicoleJoe & Nicole Members, Plex Pass Posts: 4 Plex Pass

    I was really hoping not to have to install the old processor back in the machine so I could do the comparison again. I didn't really capture any logging on the old processor because I had no reason to suspect that it wouldn't be considerably faster with the new one. Was hoping someone had some ideas that I may want to try before I go that far. I'm hoping its something obvious that I didn't consider.

    Going to try a few things then I suppose I will start grabbing logs and swapping CPU's again. Argh.

  • ChuckPAChuckPA Members, Plex Pass, Plex Ninja, Plex Team Member Posts: 22,850 Plex Team Member

    I am not suggesting you reinstall the older processor.

    I am only asking you show what you have with the current processor.

    Knowing the input data (XML), and the Passmark score (which you could also test yourself independently) we will have a metric.

    This will give you the definitive performance benchmark (you can use it for free a few times)

    It will test the CPU quite thoroughly (It's a burn-in test).

    It will output the results which can be compared with known good systems and allow objective comparison
    https://www.passmark.com/download/bitlinux_download.htm

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  • Joe & NicoleJoe & Nicole Members, Plex Pass Posts: 4 Plex Pass

    I think I figured out the problem. Perhaps even revealing a bug.

    I installed my old processor and rebooted, and sure enough, transcoding ran at 17x (the more I think about it is virtually impossible for a 1080p x264 source on this cpu). What I had failed to do was actually look at the completed transcode.

    I played the transcoded version in a browser and it had no video, just audio. I also checked it with VLC to be sure. I soon realized that I had enabled "Use hardware acceleration when available" when testing to see if an older Nvidia card I had would make any difference. When I removed the card I didn't disable hardware acceleration, assuming that since the CPU didn't have quicksync it would simply not use it. But it appears I was wrong, it just transcoded with no video?

    Anyway... after disabling hardware acceleration on the old proc, I am seeing it transcode at about 2-2.5x... which is about what I would expect, and about 1/3 of the rate I was seeing on the Xeon.

    I think there is a bug in the hardware acceleration code on my current PLEX version 1.10.0.4523... if you have HW acceleration enabled, and it doesn't use it, it should fail back to sw encoding. For some reason it didn't.

    Anyway... I appreciate your offer to dig into my logs.

  • ChuckPAChuckPA Members, Plex Pass, Plex Ninja, Plex Team Member Posts: 22,850 Plex Team Member

    Support for video cards is unfortunately your responsibility. This initial support for hardware transcoding is focused on Intel Quick Sync video. Any results / issues with GPU cards is the user's responsibility. (this is linux where we have to do all the work ourselves.. unlike Windows)

    PMS does fall back WHEN the proper HW CPU/GPU is present. The introduction of that 3rd party GPU changes everything. If it works, GREAT. If it doesn't, "Sorry". Engineering was quite specific when they briefed us about what is supported at to what extent.

    While it may look like a bug to you, it's behaving as I would expect when the libva drivers aren't correctly installed and not something I can help with.

    Does that help?

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  • Joe & NicoleJoe & Nicole Members, Plex Pass Posts: 4 Plex Pass

    Chuck,

    I enabled the checkbox to test to see if my GPU was any help. It wasn't, so I removed the GPU.. but left the checkbox enabled. Upon removing the GPU, there was no hardware acceleration available, but instead of falling back to software, it gave me an .mp4 with audio only (and did so really quickly). This condition persisted after several reboots, a BIOS upgrade, processor replacement, etc.

    Its really no big deal, anyone else would have detected and corrected the issue... I just got hung up because of the processor change. As soon as I put the old processor back in, I quickly found the cause of my confusion.

  • ChuckPAChuckPA Members, Plex Pass, Plex Ninja, Plex Team Member Posts: 22,850 Plex Team Member

    Now that you've sorted it out, what's the resolution? (I'm a bit confused haha)

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