PCI bus Bandwidth

[Humanzee]

Is there any way to measure the bandwidth being used at any given time by the pci bus? I am suspecting that I am over using what I have available once I start recording a couple of shows at the same time. With seven hard drives and 3 or 4 of them connected to a sata expansion card I imagine its possible. I've just started to get some bad recordings here and there, mostly HD recordings over the firewire. Its causing hangs in the transcoder and showanalyzer as well as lockups in sage. I thought maybe the files weren't getting written to the disk fast enough in certain instances. Event View does not show any disk errors. and I defrag regularly.

[GKusnick]

PCI bus bandwidth is on the order of 128 MB/s. A single HD stream is on the order of 2 MB/s. So it seems highly unlikely that a couple of simultaneous recordings will saturate your PCI bus.

With seven hard drives in one box, my first suspicion would be disk failure due to overheating. If it's primarily HD Firewire recordings that are being affected, then I'd suspect the STB, or possibly the Firewire cable or controller.

[Humanzee]

Oh ok, well thats good to know. I guess ill have to look for something else.

[SHS]

GKusnick you forgot to allow PCI bus overhead which can actual be much more then that.

[Humanzee]

So could it be an issue? its an older mother board, ~ 2004, no pci-e

[GKusnick]

Originally Posted by SHS

GKusnick you forgot to allow PCI bus overhead which can actual be much more then that.

Well, I did say "on the order of". Seems to me there's plenty of headroom between 2 MB and 128 MB to allow for any overhead. Unless you want to claim that overhead can take up 90% or more of the available bus bandwidth, I don't see how it could be an issue here.

[Humanzee]

it looks like from other posts, that comcast has changed some things about their set top boxes in our area. namely some change in the way signals come across firewire. I was getting some bad recordings before, but lately its seems like every other one is bad from that firewire setup. Thanks for the imput though.

[matt91]

The issue of heat may be worth at least looking into (even if not related to your current issue). I like speedfan, which reports temp, voltage and fan RPMs when available.

You might run a test of <no drive activity> to <max tuner usage> to see what happens.

Matt

[SHS]

Originally Posted by GKusnick

Well, I did say "on the order of". Seems to me there's plenty of headroom between 2 MB and 128 MB to allow for any overhead. Unless you want to claim that overhead can take up 90% or more of the available bus bandwidth, I don't see how it could be an issue here.

Just becuae it has a 128 MB PCI bus bandwidth that is only one way max capable of streaming data read or wirte communication only and you need facter in that PCI used a shared bus topology to allow for communication among the different devices on the bus which bottleneck the bus unlike PCI Express which hopely in few more years we see no more PCI bus and faster speed communication with out the bottleneck bus like we see today.