[directfb-users] Matrox G550 Poor Performance - Help.

Tue, 13 Apr 2004 00:18:13 -0700

The problem is that I have very heavy load of my CPU when I watch sat tv (Skystar2, not fully featured card).

And my computer is pretty modern - Athlon XP @2400+

 

My experiments with different movie playing and video out technologies show that not MPEG decoding but rather video output itself gets most CPU power.

 

The following is some MPlayer benchmarks. I played rather static MPEG2 - recorded by vdr 'TV test table'. So the best load was ~50%.

 

2.4.25 kernel

 

xv:

BENCHMARKs: VC:   1,029s VO:   8,659s A:   0,124s Sys:   6,223s =   16,034s

BENCHMARK%: VC:  6,4156% VO: 54,0026% A:  0,7706% Sys: 38,8112% = 100,0000%

 

xvidix:

BENCHMARKs: VC:   1,130s VO:   6,492s A:   0,125s Sys:   8,208s =   15,956s

BENCHMARK%: VC:  7,0837% VO: 40,6889% A:  0,7850% Sys: 51,4423% = 100,0000%

 

xmga:

BENCHMARKs: VC:   1,090s VO:   6,608s A:   0,123s Sys:   8,134s =   15,954s

BENCHMARK%: VC:  6,8303% VO: 41,4170% A:  0,7685% Sys: 50,9842% = 100,0000%

 

dfbmga: (to tv out)

BENCHMARKs: VC:   1,145s VO:   6,523s A:   0,122s Sys:   8,160s =   15,950s

BENCHMARK%: VC:  7,1780% VO: 40,8993% A:  0,7646% Sys: 51,1581% = 100,0000%

 

null (-vc mpeg12 -vo null):

BENCHMARKs: VC:   1,061s VO:   0,002s A:   0,124s Sys:  14,579s =   15,766s

BENCHMARK%: VC:  6,7314% VO:  0,0125% A:  0,7857% Sys: 92,4704% = 100,0000%

 

2.6.4 kernel

 

xv:

BENCHMARKs: VC:   1,001s VO:   8,591s A:   0,231s Sys:   6,214s =   16,037s

BENCHMARK%: VC:  6,2449% VO: 53,5683% A:  1,4416% Sys: 38,7452% = 100,0000%

 

xvidix:

BENCHMARKs: VC:   1,101s VO:   6,556s A:   0,119s Sys:   8,171s =   15,948s

BENCHMARK%: VC:  6,9036% VO: 41,1111% A:  0,7486% Sys: 51,2366% = 100,0000%

 

 

And to contrast the same file playback at work on Pentium 4 2.6Ghz PC with Windows XP:

 

directx:

BENCHMARKs: VC:   0.200s VO:   0.030s A:   0.000s Sys:  15.519s =   15.749s

BENCHMARK%: VC:  1.2699% VO:  0.1905% A:  0.0000% Sys: 98.5396% = 100.0000%

 

The overall CPU load is less than 3%.

 

 

People with GForces saying they have about 10 times less load on video output.

I had comparable unsatisfying results on my Matrox G550 system with Windows XP and ME...

 

The question is - what's wrong with the card? Looks like CPU does scaling/conversion - not the card...

 

Thank you.

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