[mythtv-users] Help me size next cpu,
Athlon 2800+ MP enoughfor high quality/filters?
davatar at comcast.net
Sun Feb 8 23:22:40 EST 2004
From: "J. Donavan Stanley" <jdonavan at jdonavan.net>
>I'm some of the ASUS boards have integrated Gigabit. Though they're not
>dual CPU boards.
Yes, but integrated WHERE? I already have a gig card on the pci bus.
Although running at 32/33Mhz. The nforce3 250 will have it integrated on the
chipset so it can use the full bandwidth of the hypertransport bus. It would
be nice to be able to saturate the gig card while also actually reading from
> If you're worried about CPU usage on the record, just use a PVR250 then
> filter on output / transcode. I've recorded a show, while watching a
> recording with the kerneldeint filter running and a show being
> transcodeded to MPEG4 at 3500bits/high quality/4MV and had PLENTY of cpu
> left. I only use a single AMD 2500+.
I don't plan on running bitrates over 3000kbits _ever_ Currently my
low-quality settings are at 1600kbits.
If you get the encoding and filter quality down good, you shouldn't need
that much. Consider the quality of mpeg4 you can get using ~750kbits!! (As
roughly a 2-hour dvdrip to ~675mb)
Going from 3500kbits to 750kbits is no joke as far as disk space is
concerned. While I understand that the dirty quality of cable/broadcast tv
and the lack of dual-pass encoding means I need to allow for a good amount
of extra bitrate, 3500 is nuts :) Recording pure MPEG2 even more so.
Besides, cpu's are always getting faster and have other uses, might as well
put by $200 towards a cpu, not another card. Just wanted to know if the
2800+ is "enough" or I should wait for a faster cpu later this year. If it's
sized properly it means I won't have to upgrade it for a long time.
From: "Tony Maro" <tony at maro.net>
> One note on Gigabit. Cheaper gigabit may = huge processor usage. I've
> used Linksys gigabit cards before (I think they were linksys...) that
> were dirt cheap. Sure, they push the data fairly well, but processor
> usage when moving a file was 80%+ on BOTH systems, just to do a file
> copy operation in Windows. I have zero Linux experience with gigabit.
Use jumbo frames :) Even 16k jumbo frames on intel 1000/MT cards. With
netperf I went from ~30MB/s to ~85MB/s throughput with netperf going to 9k
The one thing I know for sure is that the windows xp stack just _blows_ in
comparison to the 2.4 kernel.
running netperf on loopback yields about 130 MB/s on a barton running at
2Ghz/400 win xp sp1, about 450 MB/s running on 2.4.22 with preempt athlon
1300. So regardless of what the network card doing, the tcp/ip stack is not
going to be able to handle much without pegging the cpu.
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