Does 1/2 refresh rate work?

[Bert Pieke 7,584]

6 hours ago, SteveW said:

Maybe, maybe not. The RTSS method consumes less frames to determine the cutoff.

Just to totally confuse things.. I am beginning to wonder why I was trying to limit fps in the first place..

Simply flying with unlimited fps without an external frame limiter is as smooth as anything.. 

Remind me what the purpose actually was..

[SteveW 1,792]

You mean Unlimited+VSync=On? That's generally good enough. Without VSync just means frames are consumed above the refresh point so it's not any better anyway. With a limit just below that there's less work to do with the same frame rate.

[SteveW 1,792]

Generally, if you are 'seeing something' with the described experimentation, I would think it's not the result of perhaps a tiny bit of smoothing around 30fps, that would hardly be noticeable. If your scenery is filling in slower you could see 'smoother' and even 'more fps'.

[d.tsakiris 417]

Very interesting tool, this RTSS.

Before, I locked internally, which robbed performance, but most of the the time I would reach my target FPS. The only other tweak was FFTF=0.01. No blurries.

To test RTSS, I just unlocked internally. Very smooth FPS, and no drops at heavy-hitter situations (i.e. KSFO HD w/ 777), always at target FPS. BUT: Blurries. I guess similar to what Matt is seeing.

Now I didn't have time for further testing, and I still hope I can remedy with higher FFTF values. It might have also been my unusual test scenario: 270 KIAS at 2000 ft in the CJ. Core 0 was only at +/- 60 % (before I seldom ever saw more than 75 %), but cores 2 to 5 were maxed out, the autogen popping and then disappearing. I will report back.

Specs: I5-9600K at 4.3, GTX1070, 4.4 on SSD. P3D and FTXV on medium settings for jets.

[davetfc 4]

6 hours ago, Bert Pieke said:

Just to totally confuse things.. I am beginning to wonder why I was trying to limit fps in the first place..

Simply flying with unlimited fps without an external frame limiter is as smooth as anything.. 

Remind me what the purpose actually was..

Hi Bert,

I think I'm getting just as confused as you are...  😄

Actually, I have seen a video on YouTube describe an issue with autogen rendering when using unlimited frame rates internally (Target Frame Rate or TFR). This was for version 4.3 and 4.2, so I'm not sure if this also applies to 4.4. Here is the link to the video:

Kind regards,

Edited March 20, 2019 by davetfc
Addition

[Cruachan 705]

2 minutes ago, davetfc said:

Hi Bert,

I think I'm getting just as confused as you are...  😄

Kind regards,

Hi Dave,

I too share your confusion..lol!

I believe all these conflicting reports and recommendations underline the uncomfortable reality that much depends on the hardware in use coupled with our diverse simulator configurations and 3rd Party software choices/setups employed in any given flight situation. The importance of the latter in terms of negative impact on performance becomes less significant with multi-cored CPUs along with the ability to utilise affinity masks to optimise core sim performance and reserve non-sim Cores/LPs for certain of these Addons.

My flight preferences generally employ realistically attainable configuration settings, well coded frame-rate friendly vehicles along with choosing to avoid those well known performance sucking busy hubs and poorly optimised scenery areas. Consequently, the maintenance of an internally locked 30fps, with low percentage variations, along with the deliverance of fluid, stutter-free performance is relatively easy to achieve. This without the need for VSync, Triple buffering or external frame rate limiters. Monitoring CPU core activity and GPU usage and temps mostly confirms a stress free flight simulation with adequate performance overhead held in reserve.

Having so many options provides considerable flexibility of control. This can, with some justification, be considered a curse and yet does permit a plethora of adjustments to suit our specific needs and individual circumstances. This should be viewed as being an important part of the definition, indeed requirement, of a simulated environment.

Regards,

Mike

[SteveW 1,792]

Unfortunately fps performance does not go hand in hand with simulator performance.

The simulator maintains fps based on the number of things it draws in the scene. Cut out some things in the scene to increase fps.

The background task is filling in around the observer and that too has to perform. If it does not perform the fps continues fine.

Judders stutters and glitches in the flow are usually due to that background task overreaching or simply swinging an overly complex object into view.

[SteveW 1,792]

Experimenting with D3D and OGL code, generating scenes and looking at performance aspects of those scenes shows some things stand out as more of a problem. For example. layering of see-through objects like clouds dust and particles is heavy on the system. A single cloud sprite is not too bad but layered over another cloud sprite performance starts to suffer. A lot of differences seen in performance can just be down to the weather. Another is texture size; by just increasing sizes one notch can bring the system to a crawl.

Start with low settings, watch the LPs climb in activity, set the monitor refresh and switch on VSync, stop increasing settings when LPs start to venture over 90% when the sim is settled (not loading up).

Edited March 20, 2019 by SteveW

[newtie 533]

On 3/17/2019 at 5:29 PM, Bert Pieke said:

SO, .. where to from here?

I can limit framerates at 30 in NVI which is where I started.. seems smooth, and CPU usage on Core0 reduced..

OR, based on advice above, I can limit framerates at 30 in RTSS instead.. smoother, maybe.. not sure.. but Core0 running flat out..

OR, I can just limit at 30 in P3D itself.. certainly easier.. seems just as smooth and Core0 still running flat out..

Confused 

Maybe I'll just go back to NVI where I started..

 

 

RTSS is smoother, at least on my machine anyway. Did all that NVI testing and more.

Also, it took me a long time to stop looking at core stats and start looking at the display.

For an additional layer of smoothness, under certain conditions, use your left arrow, one click, from unlimited to 120fps.

Cheers,

Mark

[SteveW 1,792]

1 hour ago, newtie said:

Also, it took me a long time to stop looking at core stats and start looking at the display.

What the CPU is doing is fundamental to the performance, let's not forget that. No need to study core stats just need to know that the main task has overhead.

Put simply if we are climbing and go into a downdraught we might need more power to continue the climb otherwise we level off or worse, start to descend. If we are at full throttle we are going to descend, and so is our fps and our scenery fill-in will suffer too.

[SteveW 1,792]

When framerate varies, time to coincidence of frame to refresh causes the long frame stutter. Decreasing that variance hides that period irrespective of its length. The view remains smooth so long as the updated frames appear in the same period. Other things upset the flow more sporadically. Watching the display is key, look for the distance settling on a test flight that shows it like flying down the Grand Canyon or mountain valley.

To do accurate testing and comparison, save a flight at a good point on AP, perhaps about to turn onto final maybe, paused off. Start that flight each time making sure the same weather and settings are repeated.

[SteveW 1,792]

If you recall earlier I demonstrated how FSX handles vertical synchronisation in fullscreen exclusive mode. I showed how fps was not restricted by GPU vertical sync in FSX when in the windowed mode, only exclusive mode.

P3D whether fullscreen or window, is always in windowed mode. So there's no restricting it via exclusive mode functions.

Instead P3D Display settings has the VSync=On setting. This does not *control* vertical sync, instead it measures the refresh timing to attempt to output frames at that frequency. As each frame takes a different amount of time to construct, the exact time wobbles around the refresh time, it is not capped.

If it is capped then that time to next frame has the additional accuracy that decreases the wobble, and it flatlines on the cap.

A GPU tool such as RTSS can cap the frame rate. It could also mimic the appearance that the main task is always at 100% which avoids the problem of the jobscheduler assigning tasks there when it is slack. Even so that app would show a process occupying the idle time. I'll be looking into it as soon as I can fit it in.

 

 

Edited March 20, 2019 by SteveW

[SteveW 1,792]

In some circles it was suggested to cap above the refresh rate. In fact it is better to cap: At or below the rate.

One reason is that going one higher at 30fps consumes another 3.3% of the system. Also in that case it can be seen that more frames are lost as they appear too often. Another reason is that the swing back from the higher rate is further which produces a sawtooth.

When capping, make sure to bring the rate up to your expected refresh rate. It may say 60 on the box but it might be timing more precisely than that, say at 59.3. In which case you need to cap at 59 not 61.

Edited March 20, 2019 by SteveW

[Matt Piotrowski 3]

I just don't know what to do with my 144hz monitor and what settings to use. It can go to 60hz and 24hz but not 30hz for some reason. 1/2 refresh doesn't work with p3d either. I'm using 144hz unlimited with a few stutters here and there but scenery gets a little blurry.

[SteveW 1,792]

4 hours ago, Matt Piotrowski said:

I just don't know what to do with my 144hz monitor and what settings to use. It can go to 60hz and 24hz but not 30hz for some reason. 1/2 refresh doesn't work with p3d either. I'm using 144hz unlimited with a few stutters here and there but scenery gets a little blurry.

Locked, VSync=On, or Capped.

Example primary fps to go for 144/5=28.8 so you can set locked at 72, 48, 36, 28, 24, 20, 18 with increased coincidence of the frames to refresh for slightly better result. But there's not a lot in it.

If the refresh can be set at 24 then Unlimited+VSync=On in P3D display settings should be good in the sim but not so good in general Windows desktop use. So it would be better used that way only in the sim.

The NVidia app allows custom monitor configs including refresh so it might be able to be set to say 36 in a profile, but they can be tricky to set up..

An external fps cap in the GPU control panel or an app should be tried with Unlimited fps on the slider VSync=Off.