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I have an old PC I turned into a media server. It has a dedicated graphics card, and should by all accounts do what I want.

I'm struggling with transcoding via Plex (I can perhaps understand that), but even playing directly on my machine, local video files of all kinds skip and streaming video is also bad.

Windows is reporting that it's only using 3gb of the 4gb of memory installed. When playing a 720 video file I noticed that my ram and CPU was peaking at around 50% utilization.

Screenshot

How can I troubleshoot the poor performance and memory limitations?

Note: I have tried everything here to no avail regarding usable memory. Both sticks seem to function at 2gb on their own, in either slot.

  • Win 10, 64
  • Intel(R) Core(TM)2 Duo CPU E4600 @ 2.40GHz
  • 4gb Ram DDR2 667
  • Gigabyte 945GCM-S2L
  • ATI Radeon HD 2600 XT - "Excellent HD video image quality - CNET"
  • Crucial C300 SSD

My full specs from CPU-Z

square_eyes
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  • Unless you have a 64-bit OS installed, the performance is as expected. Also, that CPU of yours is really slow. It’s not suitable for 1080p unless the GPU supports it. – Daniel B Dec 09 '15 at 08:30
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    What makes you think it's only using 3GB of the 4GB installed? The 50% utilization is what you'd expect from a dual core CPU running a single core task. – David Schwartz Dec 09 '15 at 09:04
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    The 945 chipset has limitations on memory and does not fully support 4gb even on a 64 bit OS. I've seen many people with problems using motherboards based on that chipset. http://superuser.com/a/35754/19943 basically you are limited to 4gb minus the amount needed by your graphics card and motherboard devices so you will *always* have less than 4gb. – Mokubai Dec 09 '15 at 12:23
  • http://superuser.com/a/147210 , http://superuser.com/questions/312499/windows-7-64-bit-reporting-3-00-gb-usable-memory-with-4-00-gb-installed , http://superuser.com/questions/35731/how-to-enable-4gb-in-my-windows-7-64-bit – Mokubai Dec 09 '15 at 12:31
  • @DanielB I have a 64 bit OS, as mentioned in the question. Also I said 720, not 1080. In any case the GPU, which I listed supports DVI: 2560 x 1600. – square_eyes Dec 09 '15 at 20:20
  • @DavidSchwartz, you can see in the screenshot the OS is listing 3gb - top left in the image. Also (not pictured) my system properties says 4gb, 3gb usable. You can also see in my CPU-Z report I have 4gb installed. – square_eyes Dec 09 '15 at 20:22
  • @Mokubai thanks for some real help. And thanks for reading the question! - OK so I'm railroaded by the chipset RAM-wise for utilising 4gb. I still can't understand why 2d video performance is so bad though. Or that only half (1.6) of the 3gb usable (of 4gb installed) is being accessed when I was playing a problematic file. See the screenshot. It's maxed like the CPU is. – square_eyes Dec 09 '15 at 20:24
  • You misunderstand. I’m just making clear that your CPU is really slow. 720p CPU decoding is possible, but only with codecs supporting multithreading. Firefox probably won’t cut it. 1080p playback might be possible. Your GPU supports it, but again, the codec has to support it too. – Daniel B Dec 09 '15 at 21:01

1 Answers1

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Your memory issue is a chipset limitation. The 945G's address decoder only supports a 4GB address space, so anything else that has to go in low memory (such as device mappings) reduces the RAM available to the OS.

The (G)MCH provides a maximum main memory address decode space of 4 GB (2 GB for the 82945GC/82945GZ /82945PL). The (G)MCH does not remap APIC or PCI Express memory space. This means that as the amount of physical memory populated in the system reaches 4 GB (2 GB for the 82945GC/82945GZ/82945PL), there will be physical memory that exists yet is nonaddressable and therefore unusable by the system. -- 945G chipset specification

Your BIOS is pretty old and probably reserves 1GB for low device mappings just to make sure it has enough space. This is probably more than is needed and there might be a BIOS option to change it, but it's not that likely because at the time your BIOS was developed, this wasn't a significant concern. Neither 4GB systems nor 64-bit OSes were common on mid-range consumer systems.

... Or that only half (1.6) of the 3gb usable (of 4gb installed) is being accessed ...

You're misunderstanding this number. All of the usable memory is being used, except for a very small amount that has to remain free in case interrupt handlers require memory. The 1.6GB is primarily the amount that's being used to directly service application requests, and the system can't use more for this purpose than the applications request. The balance is used for other purposes such as caching.

The CPU issue is because the program you are running is only using a single thread at a time to do its computationally-intensive work. One thread can only run in one core at a time. So the maximum load it can place on a dual-core CPU is 50%. Depending on what program you are using and how you are using it, you may be able to get it to run in a multi-threaded mode that let it take advantage of more than one core.

David Schwartz
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  • OK thanks for the response. It's really helpful to summarise all the issues at hand. Disappointing for me as I feel like my video card should still handle some semblance of HDMI. With RAM of its own, and a DPI well above 720p I had hoped it would cover it off. Edit: I just saw your other comment. So CPU seems to be a limitation here, and I'll need a multi threaded player/codec to overcome that. Odd that CPU is a bottleneck for an otherwise capable (for my purpose) GPU. But I gess there is more at play than I fully understand. – square_eyes Dec 09 '15 at 22:29
  • @square_eyes Your GPU won’t do anything by itself. The video decoder has to support *and* use it. – Daniel B Dec 10 '15 at 09:32
  • So is there any hope? I could buy a new machine, but this is a bit of a project. I assumed VLC, Plex etc would be able to access the video card through the system drivers. But my knowledge of codecs is limited. Is it simply not enough to have the codec for the file you are viewing installed? – square_eyes Dec 11 '15 at 01:48