Question / Help Realistic Performance expectations with my setup?

[Xerouz]

Hey all. I just wanted to know if anyone can give me in inkling of a realistic expectation with my setup. I'm getting performance that is below what I want, but I'm wondering if my expectations for my system are just way too high.

My computer specs are as such:
CPU - AMD Phenom II 940 black (OC @ 3.3GHz)
GPU - nVidia GeForce GTX 460 1GB DDR5
RAM - 8GB Corsair DDR2 (833MHz)
600GB Western Digital HDD
80GB Intel SSD
Internet - 23Mbps down/ 3Mbps up.

I can't really remember all my settings I have set for OBS, except that my resolution is 1920x1080 downscaled to 1280x720x30. The encoding preset is set to superfast.
Here is an example of a stream I did with this setup: http://www.twitch.tv/scxerouz/b/337385013 . It goes fine, but toward the end I seem to be dropping frames, as it freezes up when more stuff gets on screen. Audio itself never seems to stutter. My ingame settings for Starcraft are all on low. I get an FPS of around 60 (with VSync enabled), until toward the end, when it drops down around 25-30, then the video in the VOD starts stuttering. It should be noted the stuttering is not present in game, just in the video.

Is there a combination of settings I can try that may get better performance, or am I expecting too much out of my older system?

 

[ruxxar]

What are your bitrate and buffer size values?

Also, you should turn V-sync off.

 

[Xerouz]

My bitrate and buffer size are set to 1500kbps. I turned on V-Sync because I read that can help keep up performance because the game isn't trying to render frames above the 60fps. Maybe that isn't true?

 

[ruxxar]

1)

Here's a concise explanation of how Vsync works http://hardforum.com/showthread.php?t=928593.

Basically it limits your fps to (Monitor Refreshrate/N) where N is a positive integer. If your GPU is able to process a FPS over the R/N, then your FPS will be limited to R/N. But if you just dip below R/N, just by a couple frames, your fps will now be limited to R/(N+1).

Example :

Your monitor refresh rate is 60 hz. In a low intensity scene your GPU is capable of producing over 60 FPS. At this point your FPS will be limited to 60 fps.

In the midgame you get into bigger clashes and your GPU can no longer produce over 60 FPS. Your fps will now drop to the next level of R/N+1 which would be 60/2 or 30 fps. This is a big drop in fps and could be is quite noticeable at the moment when the shift happens.

Please note that this is for double buffering Vsync, there is a technique called triple buffering that alleviates some of this, but I don't know which one SC2 uses.
This could be one of the culprits for you lag when you jump between 2 limits of FPS with Vsync on. With Vsync off you will get the FPS that your GPU(and CPU!) is able to produce and will get a much smoother transition of FPS, rather than a big jump.

I would recommend turning Vsync OFF

2)

With 1500/1500 you have the possibility of spiking up to 3000kbit/s, which could possibly be an issue.

I would recommend turning your buffer size down to 1000 so that you'd at max would spike up to 2500kbit/s.

 

[Muf]

ruxxar, in a streaming situation, normal guidelines regarding vsync don't apply, because you are not only trying to keep your game smooth, but also your stream. If the game is forced to render at either 60 or 30fps, and wait the rest of the time, it leaves more free CPU and GPU for OBS to use to present and encode the stream. So in this case, leaving vsync on is preferable, especially since Xerouz has such a low spec system.

It should also be noted that nvidia has Adaptive VSync which offers the best of both worlds.

 

[ruxxar]

It should also be noted that nvidia has Adaptive VSync which offers the best of both worlds.

Oh wow. That is really smart. As the editor say, it's really strange no one had implemented that before.

@OP:If you have access to adaptive V-sync it indeed is the best choice.
(runs away checking if I have adaptive Vsync on my GTX570)

 

[Xerouz]

Thanks for the information. I'll try it. I guess I'm asking a little much from my system. It seemed like a beast system when I built it four years ago. I guess it's time to start upgrading. Maybe jump off the AMD train and onto the Intel one.