7600GT or 7900 GS KO?

[OttoNP]

7600GT or 7900 GS KO?

Looking at these two to go to instead of my 7300GT to try to get smoother HDTV playback...similar price, 7900 GS seems to score significantly better in benchmarks i've seen, but they are mostly game type benchmarks. Not sure how they would correlate to sage hdtv playback...

outputing 1080p to sony HDTV...

[Steve52]

I don't have one, but from what I have read the 7600GT would be much better for HDTV.

[OttoNP]

I'm not sure, the 7600GT has higher clockspeed but the 7900 GS has more pipelines and does better in all the benchmarks i've looked at. Granted they are mostly for games, but many games use directx which is what i think sage usings during VMR9 mode...

I'd like to really understand better the interaction between raw file, decoder, graphics card and what you see on the screen during playback in vmr9 mode...

[cslatt]

The analysis that I've seen indicates that, all features being equal (aka within the same class of GPU), Purevideo performance corresponds directly to clock speed and has nothing whatsoever to do with the # of pipelines or any other portion of the 3D hardware. Here's a quote from AnandTech:

As PureVideo HD performance is dependant on the GPU's core clock speed, the impact of PureVideo will vary depending on the speed rather than the 3D power of your graphics card. For example, our MSI 7600 GT HDCP runs at a default 580 MHz core speed. This makes it a more effective PureVideo card than a 7900 GT running between 450 and 500 MHz. NVIDIA allowed us to underclock the MSI graphics card and test a variety of settings between 350 MHz and 580 MHz in order to fully understand the way performance varies versus GPU clock speed.

To test the performance of PureVideo HD, we ran perfmon while playing back Riddick at different GPU clock speeds. Riddick was playable down to 450MHz, and PureVideo HD did have some impact on performance even as low as 400MHz. There wasn't any perceivable quality difference between running the GPU at 350MHz and running without GPU acceleration.

Without PureVideo HD running The Chronicles of Riddick (Japan), the CPU was at 100% the entire time. Enabling PureVideo HD with the GPU running at retail speed (580MHz), CPU usage dropped to about 80% on average. With other titles using VC-1 content, we saw CPU usage at around 80% without GPU assistance. Turning on PureVideo HD gave us about 60% CPU usage. In general, it looks like a 580 MHz NVIDIA GPU is capable of decreasing the load on a Pentium D 830 by about 20% in any given situation. This isn't a huge drop, but it is definitely significant and can help in those tough situations (like H.264 encoded imports).

[UFGrayMatter]

Originally Posted by OttoNP

7600GT or 7900 GS KO?

Looking at these two to go to instead of my 7300GT to try to get smoother HDTV playback...similar price, 7900 GS seems to score significantly better in benchmarks i've seen, but they are mostly game type benchmarks. Not sure how they would correlate to sage hdtv playback...

outputing 1080p to sony HDTV...

the 7300GT should be plenty of power to do what you want. What problems are you having that you'd want to upgrade? I have a 7600GS and can do 1080p.

[OttoNP]

I have only been able to get acceptable playback using overlay and the below settings in VMR9 with 7300GT:

1080i requires nvidia video with ac3 decoder in film mode 30 frames/sec
720p with surround nvidia video with ac3 decoder in any mode 60 frames/sec
720p with stereo sound nvidia video with any audio decoder 60 frames/sec

i say acceptable, but I still pick up on the occasional stutter, which can drive you crazy watching for it....

Searching through the forum there is a thread outlining the different nvidia cards and how clock rate is very important for video playback. They also mention altering the clock rate to determine theshold for stutter free playback. They found this to be around 390-410 mhz, whereas my 7300GT is a mere 350mhz. So, my experiance is correlating with their tests putting my card on the borderline of smooth hdtv playback.

I took the high clock advice and got a 7600GT with 560mhz and it has made all the difference. Annoyingly I still have to choose some settings and FSE mode seems to make a large difference with the 7600GT (I could tell little difference with 7300GT). It is better in all conditions and I can watch 1080i in any video mode at 60 fps now. SD TV also looks a lot better to me. Right now I'm using nvidia video in smart, acfilter, fse and get smooth playback where i don't pick up on anything. Even with overlay and the 7300GT I would pick up an occasional stutter.

My dilemna now is DVD playback locks my computer when using AC3 filter, but works ok with nvidia audo decoder; it is annoying me that after I switch one filter to the default it is difficult to switch back or view the other filter's settings...