P3D multicore usage anomoly

[Mace 1,927]

2 hours ago, SledDriver said:

Thanks for all that guys. I will be doing more tests later today.

Noel/Mace, could you just confirm what method you are using to limit the fps to 30? RTSS? Other?

I am presently running with vsync ON and framelock at Unlimited.

I run a 30 hz refresh rate on a single 4K screen.

I do not use RTSS.  Isn't that for 60 hz refresh users?

[SledDriver 39]

9 hours ago, itsjase said:

Do you know your cpu frequencies sled? And monitored them before and after the disable/enable?

All 6 cores at permanent 5GHz. No speedstep or any other Hz reducing BIOS tech is enabled. Also locked at 5GHz during AVX.

I should add the main job of this PC is powering a music production suite, where timing is critical, and it is common practice in this usage to disable all the power saving and Hz modifying tech in BIOS.

Maybe this is something the sim world has never considered, and which might be useful, being as it is another real-time, timing-critical application.

All these things slowing down your chip to try and save the planet are perhaps not really suitable for real-time applications. It certainly makes a significant difference in audio applications, so I don't see why it shouldn't in sims.

Edited April 17, 2019 by SledDriver

[SledDriver 39]

18 minutes ago, Mace said:

I am presently running with vsync ON and framelock at Unlimited.

I run a 30 hz refresh rate on a single 4K screen.

I do not use RTSS.  Isn't that for 60 hz refresh users?

Exactly, hence my question. My monitor refresh is at 60Hz, so a simple Vsunc isn't enough to limit it to 30fps, or did I misunderstand something.

[Mace 1,927]

1 minute ago, SledDriver said:

Exactly, hence my question. My monitor refresh is at 60Hz, so a simple Vsunc isn't enough to limit it to 30fps, or did I misunderstand something.

Since you are at 60 hz I would be investigating this RTSS app.

I can't say I paid very close attention to that thread, as to the details of how it works. 

 

[Noel 4,501]

1 hour ago, SledDriver said:

Exactly, hence my question. My monitor refresh is at 60Hz, so a simple Vsunc isn't enough to limit it to 30fps, or did I misunderstand something.

Sled, some monitors can be set to a refresh rate of 30hz, which is the case w/ my Dell curved 3440x1440 screen.   There are external limiters but I'm guessing they won't work for the task of syncing to a monitor's vertical refresh rate.  Perhaps if your screen won't do 30Hz maybe there is a utility that will allow that to happen w/o harming your screen.   Have a look and see if it's an option in your nV control panel which is where I set refresh rate thru.  What would really be a holy grail would be to have the horsepower to sync to a 60Hz refresh rate and be able to always sustain at least 60fps in P3D.   This would be the ultimate in smooth video display I'm sure.   You could certainly do it in less demanding scenarios to try it out.  Just make sure you keep frames unlimited in sim.  You would want to display CPU utilization during this such that when you start dipping below 60fps you would start seeing loss of ultra smooth video.

Edited April 18, 2019 by Noel

[SledDriver 39]

1 minute ago, Noel said:

Sled, some monitors can be set to a refresh rate of 30hz, which is the case w/ my Dell curved 3440x1440 screen.   

OK I getcha.

[Noel 4,501]

Check in nV control panel to see if it's an option for you it may well be.

[itsjase 52]

You can set your iN sim limiter to anything between 33-57fps and triple buffering off. 

This will lock it to 30 vsynced

[Noel 4,501]

8 hours ago, itsjase said:

You can set your iN sim limiter to anything between 33-57fps and triple buffering off. 

This will lock it to 30 vsynced

That is the most bizarre piece of information I've heard yet!  Was it tongue in cheek and if not where did it come from?

[SledDriver 39]

My Dell 24" is 60Hz according to nVidia Control Panel. No option for 30Hz.

I can set a custom profile for the monitor at 30Hz, but I have no idea if this is good for the monitor - I know it's lower, but don't want to risk breaking it over time.

[Sethos 4,336]

1 minute ago, SledDriver said:

My Dell 24" is 60Hz according to nVidia Control Panel. No option for 30Hz.

I can set a custom profile for the monitor at 30Hz, but I have no idea if this is good for the monitor - I know it's lower, but don't want to risk breaking it over time.

Won't hurt it whatsoever.

[itsjase 52]

1 hour ago, Noel said:

That is the most bizarre piece of information I've heard yet!  Was it tongue in cheek and if not where did it come from?

No not tongue in cheek. Vsync limits your framerate to multiples of your refresh rate, so 60fps. If unable to reach 60fps then it will drop to 30fps.

Triple buffering allows vsync to run framerates other than these multiples because it keeps a 3rd frame in the buffer (as per the name) which it can use to fill the "gap" between 2 vsyncs, though this introduces stutters.

So locking it at any number below 60fps with vsync on and triple buffering off will force it to drop to vsync at 30fps.

Try it if you want

[Noel 4,501]

3 minutes ago, itsjase said:

No not tongue in cheek. Vsync limits your framerate to multiples of your refresh rate, so 60fps. If unable to reach 60fps then it will drop to 30fps.

Triple buffering allows vsync to run framerates other than these multiples because it keeps a 3rd frame in the buffer (as per the name) which it can use to fill the "gap" between 2 vsyncs, though this introduces stutters.

So locking it at any number below 60fps with vsync on and triple buffering off will force it to drop to vsync at 30fps.

Try it if you want

Easy enough to try and it will be readily apparent if the outcome is identical.  FWIW I have triple buffering on w/ the monitor set to 30Hz.   I never had any good result from limiting internally, but it's been so long since I tried it I'm curious.  Theoretically I can put my screen back to 60Hz, internally limit to any number mentioned, and output end up at 30 frames per second.  Hard to fathom but easy to test.

[Bert Pieke 7,585]

3 hours ago, Noel said:

Easy enough to try and it will be readily apparent if the outcome is identical.  FWIW I have triple buffering on w/ the monitor set to 30Hz.   I never had any good result from limiting internally, but it's been so long since I tried it I'm curious.  Theoretically I can put my screen back to 60Hz, internally limit to any number mentioned, and output end up at 30 frames per second.  Hard to fathom but easy to test.

This topic is taking many twists and turns... I just tested what you are proposing and can support that simply turning Vsync on in P3D, with no triple buffering, and with fps set to unlimited, reduces the fps to 30 (with a 60 Hz monitor).

More interesting, to me, is that is also reduces both CPU and GPU load.

When I was using RTSS with the Scanline X/2 option, the GPU load was reduced, but the CPU load stayed constant!

The remaining question is how fluid flight and scenery loading are affected.. with RTSS both were very good... am I now going to get microstutters or slow loading scenery tiles???  Will report back after a few flights..

 

[lownslo 592]

6 hours ago, itsjase said:

So locking it at any number below 60fps with vsync on and triple buffering off will force it to drop to vsync at 30fps.

No joy here.  Running with no frame rate limiting at all my system will run at 30-50fps during my test flight (the same test I've used since FS9).  If I enable Vsync and lock frame rate to 59 I simply see the same 30-50fps... but with a jerky, lagging scene on my monitor.  Looks like the scene is being held back/dragged ahead based on the varying frame rate.  If I lower the framerate limiter to 40, the frame rate varies between 30-40.  The jerky scene on my monitor isn't quite as bad but still unpleasant.  If I set the sim's FR limiter to 31 the frames vary between 30-31, and the scene flows smoothly across my 60hz monitor.

Cheers,

Greg