Note regarding half refresh-rate v-sync

[adi518 73]

I know a lot of people use this tweak via NVI, which also means limiting your frames to 30 using an external limiter of some sort.

 

Well, I tried several times to use this 'tweak', but ultimately, all I got was lower fps and degraded experience. During my mess around with this tweak, I set my limiter to unlimited. I then, couldn't figure out why I'm having weird stutters and low fps when going full screen. Ofc, that's because vsync regularly only works in full screen mode. So half refresh-rate without a limiter is actually disturbing fsx. Everyone who often wonder why they have fps issues and do not use a limiter, make sure vsync settings is set to default in NVI fsx profile. I was suffering for like a week until I got to the realization it's the half refresh rate thing causing it.

 

Just something to bare in mind.

[SolRayz 392]

I posted this in another thread...I know this goes against all orthodoxy, but I've been getting some stellar performance running unlimited. I am usually internally locked at 40 with Forced V-sync in NI, but at times and dependent on the situation, unlimited is preferred. The sim stabilizes itself in the 50-60 range and the smoothness is simply breathtaking. I really adjust it now depending on my situation.

[787flyer 633]

Hi,

 

I

 

Ofc, that's because vsync regularly only works in full screen mode

 

I think you will find there is also a fix/tweak available now to also get this working in Windowed mode.

If you want to know more the latest FSX tweaking guide to be found in the Tutorials section of this site shows how this can be done.

http://forum.avsim.net/tutorials/article/66-read-before-posting-software-hardware-guide-for-fsx/

 

I am able to achieve good frame rates in Windowed mode, very few stutters and limiting the frames to 30FPS within FSX.

 

Regards,

[adi518 73]

I posted this in another thread...I know this goes against all orthodoxy, but I've been getting some stellar performance running unlimited. I am usually internally locked at 40 with Forced V-sync in NI, but at times and dependent on the situation, unlimited is preferred. The sim stabilizes itself in the 50-60 range and the smoothness is simply breathtaking. I really adjust it now depending on my situation.

That's exactly (unlimited) how I have it setup and I'm very happy with it.

 

 

Regarding vsync in windowed mode. Yes, I know. I wrote "regularly vsync" as in relying to the normal usage of v-sync.

 

This is just something to bare in mind in case you have fps problems without understanding why. People who don't even know what vsync does are more prone to get issues with it.

[HansRoaming 73]

Thanks for this, I use vsync to stop tearing really with TrackIR and will switch from half to normal from now on.

[adi518 73]

Here is what vsync does:

 

Say your gpu is rendering fsx @ 200 fps and your monitor is a regular monitor that's running at 60 hertz. Notice how the monitor's refresh rate is in bind with the fps, but does not limit it. However, when the fps goes > 60, the horizontal image and vertical image become out of sync, resulting in what we call "tear". So essential for it to be in sync, the fps and refresh rate have to be locked together. In our case, the fps is constantly "200", we can then turn On vsync and it will cap the fps down to the highest refresh rate possible, in our case 60, and we will get 60 fps and no tear effect.

 

Now obviously, maintaining such high fps is not feasible by most, not just in fsx. So in reality, once your fps goes < 60 and vsync is enabled, your fps will degrade from 60 to 30 and from 30 to 15. That's what it has to do in order to maintain synced display.

 

So half-refresh rate in NI, is basically telling the monitor "lower your refresh rate to 30". And then, when your fps > 30, you start noticing hiccups and low fps. You actually just limited yourself. Now.. some people deem 30 fps to be smooth. It is true that some people do not see a difference between 30 and 60, but there is quite a significant difference (whoever plays fast-paced games knows). While I tried this vsync tweak, it gave me nothing really.

 

Also something to bare in mind. When people make youtube movies that seem really smooth and nice.. it's not always like that while they're actually playing. When the video is getting processed by youtube or a video editing software, it becomes a little smoother, thus giving the illusion it is "perfectly smooth".

 

Last for now, a while ago, NV added a new feature in it's drivers. It's called "adaptive vsync". Adaptive vsync is virtually the best of the two worlds. Your fps will be capped to 60 if you're able to maintain it above 60 (hence vsync is enabled) and vsync will disable on-the-fly if you can't maintain above 60 anymore. To clarify, here's a reminder: with vsync On and fps < 60, we will be down to 30 fps and then 15 fps. Hence, we just lost precious fps because we forced vsync. Turning vsync Off, will gain up those fps but may cause a tear or two. Still, everyone would prefer more fps. So this is what adaptive vsync was invented for and I use it for every game out there (well, almost).

 

Unfortunately, adaptive vsync isn't going to cope well with fsx, that's because fsx fps are best when the limiter is set to unlimited which is way above 60.

 

I hope you now understand what it all does.

[jabloomf1230 2,445]

 

 

Last for now, a while ago, NV added a new feature in it's drivers. It's called "adaptive vsync".

 

Adaptive Sync is only for SLI mode. Someone else here tried using that setting for FSX and a single GPU and it nothing.

[adi518 73]

If you globally say that AV is only for SLI, well that's plain incorrect and misleading. FSX wasn't made with SLI in mind, we all know that. However, AV works perfectly well with lots of modern games, with either 1 gpu or SLI. This feature has nothing to do with how many gpus you have.

[jabloomf1230 2,445]

What? No. Let me rephrase this. AVS was designed  by nVidia for SLI where you consistently get performance above 60 FPS. It enables VSync above 60 fps and disables it below 60 fps.  I never said anything about FSX in SLI. What I said was that someone here tried AVS with FSX and a single GPU and it did nothing. 

 

Besides, it's mostly broken in recent drivers and hasn't worked in a while in Win8 altogether. It's another nVidia gimmick, at best.

[adi518 73]

Ahh.. well not just for sli. Some games will render @ > 60, like bf3, if you have a single 680, and then AVS comes in very handy.

 

Like I previously said, it's pointless to use AVS in fsx because it will supposedly not work or limit fsx to 60 fps while fsx works best with limiter set to "unlimited".