What are the recommended backend specs for HD?

My current backend is an Athlon 1900+ with 512MB of RAM. On this I have 1.1TB of storage space, two analog tuners (PVR-150 & PVR-350), and a PCHDTV5500.

So far it seems to be holding up okay. I started out with 256MB of RAM, but I pulled a 512MB out of another computer to beef it up a bit. I was trying to fix stuttering audio, but that actually seemed to be fixed through a setting to buffer the audio.

I would however, like to know if I should be planning an upgrade. What are my limitations here? I would think that the only time the processor is ever really being used is to flag commercials. I'm not sure what role the memory plays. I used TOP with the 256MB stick and I was using about 250MB of RAM, and now that the 512MB is in it's saying that about 500MB are in use. I'm not sure what it's doing with that extra memory...

I have a gig of ram in mine, and I'm doing SD only. It normally sits at around 512m used, going up to 1g during transocding/commflagging. When I had only 5512m in it, it would dip into the swap file, but now with 1g, I've only seen it do that a few times, and that was when I first added the 1g.

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KM R5E50; K8NGM2; A64-3800+; 1024MB PC3200; LG DVD-RW; Seagate 750GB; 6600 PCI-E; Onboard sound; Hauppauge PVR-150

I was running SD with 256MB of RAM just fine...

Does anyone know what major role the memory has in the MythTV backend. Does it impact streaming capability? Should I move to 1GB? Remember, this is a backend only, no decoding is done by this computer.

Well, right now I'm having problems watching HD shows if the backend is doing anything else. If one of the tuners is recording a show, even the analog ones, the video will stutter periodically. I guess it's time for an upgrade...

Okay, I'm dumb...

I upgraded my backend and I still have problems with HD (I love how fast mythweb is now, though). For one thing, I have 1GB of memory and when I run TOP it seems to be using it all. Is that just how MythTV works? Use all memory available?

Anyway, the reason I'm dumb is because my problem is with the processor in my Frontend. I still had video flicker problems and I decided to run top on my frontend to see what was going on. My Processor was staying in the 90% range whenever I was watching HD shows. I don't like XVMC, so I'm looking into upgrading my processor.

I have a few options. I can try just upgrading the processor, or I can upgrade the mobo and processor. I have an Athlon 2600+ in there right now. I have a 2800+ I can put in. Does anyone know if this is worth my effort, or should I just upgrade to a much faster processor?

Thanks.

Me too!


You'll find this is not KnoppMyth/MythTV specific. Linux in general will appear to "use" all available memory via top when in fact it is actually not using all the memory, but memory it (I believe) has reserved based on usage. See http://aplawrence.com/Bofcusm/2118.html and http://rimuhosting.com/howto/memory.jsp for some more information (both dated I realise, but still pertinent)


I've had perfect playback with 0% idle CPU according to vmstat, you may want to use that to gauge your usage. I wouldn't recommend running under 0% idle, however


In my testing I would say not worth the effort. I don't see where you mention which version of KM/MythTV you are using (please see http://mysettopbox.tv/phpBB2/viewtopic.php?t=13537), so I'm working off my experience with R5D1 here. I am currently experiencing stuttering/pausing with an Asus M2NPV-VM, Athlon 64 3200+ and 512Mb DDR2 533 RAM. Not all of the time, and I am still testing with various playback options within MythTV.

As you have found, it's not the backend that hinders HDTV playback, it's the frontend. This is one case where "more is more", and you want to load up on the frontend as much as possible hardware-wise. You may want to take inventory of all of your current systems (backend included) and start swapping some components around. I have found the least problematic HDTV playback so far to be with an ASRock P4i65G, P4 3.0Ghz/HT processor, 512Mb RAM and a GeForce 6200LE. A lesser processor may work with more memory.

Thanks Slow. I am running R5D1 as well.

I'm planning on purchasing some new hardware as my current stuff is limiting my swapping capabilities. My frontend is a nice-looking Silverstone case, but as a result I'm limited to a uATX mobo. I have an Athlon XP 64 3500+, but I don't have a uATX socket 939 mobo. I already have 1GB of RAM to work with. So, I'm planning on buying another Athlon XP 64 3500+ (it's only $75...), a new mobo, and a Geforce 6200 (they all only seem to have 64MB of RAM, is that the case with yours?). I'm hoping this will put me where I need to be.

I'd like to be able to watch the Superbowl in HD without any stuttering and the ability to pause, rewind, etc... So I'm going to work fast on this. If anyone thinks I'm making a mistake with this hardware choice please speak up.

The best advice is and has been to put your money into the frontend. That's what I did, and it pays dividends especially WRT HD. I built a psuedo-Dragon for a frontend and it behaves itself quite well doing HD

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R7.3 Backend
CPU: 1.8 GHz
RAM: 2Gb
Drives: 500Gb IDE; IDE DVD-RW
Mobo: eMachines
Tuners (Analog): PVR-250
Tuners (Digital): DCT-6200 Motorola Cable Box, HDHomeRun (OTA + cable)

I would recommend a geforce 6150 based motherboard. You can get them in either socket 939 or AM2, most have onboard DVI, VGA, component video, optical and coaxial digital audio, and most are uATX. Then you can skip the 6200 card.
The best of the 939 boards is the one I have, the MSI K8NGM2-FID. I'm not too familiar with the AM2 boards. Go to newegg and search for nforce 430 or geforce 6150 to see what is out there.

Edit: I would spend a couple extra bucks and go dual core, check out this x2 3800+ AM2 for $97:
http://www.ewiz.com/detail.php?p=ADO-38 ... 1656d67e36

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MythTV box: Opty 170, MSI K8NGM2-FID, 1.5 GB PC2700, Seagate 7200.10 400GB, Lite-On Combo drive. PVR-150, HDHomeRun. Antec Sonata, Freezer 64 Pro. Oh so quiet.

Thanks for the tips, but I already placed my order...

I'll let everyone know how it goes. Worst case scenario I can upgrade just the processor after all these changes.

Modemboy, I thought about using the motherboard video, but I need DVI out to go to my HDTV and I couldn't find a motherboard that worked for me and had DVI out.