Yep, I do use TrackIR and was actaully going to add that to my comment since I think that might be why I prefer unlimited over limited FPS. I simply cannot achieve the same kind of smoothness moving my head with locked FPS.

 

However for anyone not using TrackIR locked FPS might very well be the way to go.

If you haven't locked below the achievable fps, then you haven't locked. I would give it another chance, specially if you're using Tir. If locked didn't work, it was simply set too high. Locked works, I'm using 20.

 

A test I like to use; Setting Unlimited fps, then just after take off, I set the AP and I'm heading for the IDF on a reliable path. With the outside view I look back at the aircraft, so that the airport is in view, and save the flight so I can run from startup this view. Once the IDF is reached the aircraft starts the first turn and the airport swings out of view, depending on where I'm departing, perhaps more urban comes into view. Keeping a log of the fps trace reveals a lot about the setup of the sim. With Unlimited fps setting I can see a stutter as new scenery comes into view, but that's OK for now since I'm only interested in raw performance at this stage. When I've settled on a setup that gives the smoothest trace, I can select fixed fps (which is not just a limiter) so that there is headroom for the look ahead frames. Now when I start the flight and the AP makes the turn, the sim stays smooth. It's not just looking back that this happens, it's the same inside the VC. Having said all that, simply spinning the outside view, comparing with and without locked is a convincing reality check for me.

If you haven't locked below the achievable fps, then you haven't locked. I would give it another chance, specially if you're using Tir. If locked didn't work, it was simply set too high. Locked works, I'm using 20.

 

A test I like to use; Setting Unlimited fps, then just after take off, I set the AP and I'm heading for the IDF on a reliable path. With the outside view I look back at the aircraft, so that the airport is in view, and save the flight so I can run from startup this view. Once the IDF is reached the aircraft starts the first turn and the airport swings out of view, depending on where I'm departing, perhaps more urban comes into view. Keeping a log of the fps trace reveals a lot about the setup of the sim. With Unlimited fps setting I can see a stutter as new scenery comes into view, but that's OK for now since I'm only interested in raw performance at this stage. When I've settled on a setup that gives the smoothest trace, I can select fixed fps (which is not just a limiter) so that there is headroom for the look ahead frames. Now when I start the flight and the AP makes the turn, the sim stays smooth. It's not just looking back that this happens, it's the same inside the VC. Having said all that, simply spinning the outside view, comparing with and without locked is a convincing reality check for me.

 

I've already been down this road far too many times tested with locked vs unlimited and I did try locking at a low value such as 20 to make sure the locked FPS would be achievable but in the end unlimited gives me the most smooth experience and right now my simulator is performing reaaly, really good so I'm using my free time flying rather than tweaking. Especially when there's nothing to fix at the moment with everything working just perfect :smile: 

Well normally TrackIR shows stutters far more than not useing it, I use TrackIR and hence why I lock at 30. But this just shows finding what works for one can be totally different for someone else.

 

Well, yes the explanatory quote is fine and logical. The problem stands with the actual implementation.
When using fixed, the look ahead frames not just 'eat' into the maximum available fps, but depending on the system and quantity of installed stuff, can easily eat up 20-30 percent of the fps.
Sometimes it works fine for folks (usually those not using extremely dense airports or max scenery density setting) but it becomes counterproductive exactly when the highest possible detail is needed or preferred by the user.

I don't want to go into the technical detail here, but the better the hardware resources are, the benefit of using internally limited fps becomes proportionally less and less.

Subjectively, I tried and tested all available combinations both FSX and P3D, on different machines, and the result has always been the same: Using unlimited AND using a descent external limiter (like Dxtory) ALWAYS gave me the better and best results, regardless the theory of look-ahead-frames.

BTW, the part, using look-ahead-frames to improve the physics of the aircraft is plainly wrong, that's why - fortunately - the dynamic capabilities (if well designed) work so well in the sim(s), regardless the fps matter...

Potroh

 

I've already been down this road far too many times tested with locked vs unlimited and I did try locking at a low value such as 20 to make sure the locked FPS would be achievable but in the end unlimited gives me the most smooth experience and right now my simulator is performing reaaly, really good so I'm using my free time flying rather than tweaking. Especially when there's nothing to fix at the moment with everything working just perfect :smile:

Cool, I acknowledge that setting and using fixed fps is just a different set of compromises to using Unlimited, and can take up more time or simply never works well on some systems.

BTW, the part, using look-ahead-frames to improve the physics of the aircraft is plainly wrong, that's why - fortunately - the dynamic capabilities (if well designed) work so well in the sim(s), regardless the fps matter...

The handling of the aircraft is affected in the same way as the panning view.

 

 

The handling of the aircraft is affected in the same way as the panning view.

 

Well, not really. Sorry.

Those are two (and actually more) different aspects of the priority handling of internal processes of the sim, which are only superficially related to the display engine's "virtual priority".

 

We have been through this hypothesis long ago at the companies I work for (mainly Aerosoft, FlightsimLabs, Prosim737) when we tried to consider doing an external flight model.

It simply turned out (after several weeks of thorough testing) that it's simply not needed...

 

Potroh

Well, not really. Sorry.

I can see for myself by not least of which, flying...

Majestic proved how good it can work when the FM is uncoupled

 

 

I've already been down this road far too many times tested with locked vs unlimited and I did try locking at a low value such as 20 to make sure the locked FPS would be achievable but in the end unlimited gives me the most smooth experience and right now my simulator is performing reaaly, really good

 

 

but depending on the system and quantity of installed stuff, can easily eat up 20-30 percent of the fps.

 

I'm hitting the same conclusion as you folks (particularly on my new rig). Going back to the topic, another curious observations on the new system is a higher FFTF (e.g. the default) seems to provide a smoother experience, and is contrary to what I used to get before I upgraded. To your conclusions Potroh, I assume this is because there is now enough processing headroom per frame-time without having to throttle the autogen / terrain paging.

 

This will be an even more interesting discussion when SLI comes into the picture in a few weeks...!

This is why I have always found texture loading better with fps locked and always smoother. You cannot run at full out and then not exspect stutter etc when the sim needs to load something and you have given it no head room at all.

 

30 fps Locked LOD 6.5 and with 0.01 =Job done, perfect texture loading and smooth. If you run unlimited and get stutter or poor textures loading you know why. :smile:

 

I did a flight from FT Toronto to FB KIAD I entered a total placket of cloud at FL32 ASN and cloud coverage set to max within P3D and only came out of it at FL 7000 and there was KIAD approach and area perfectly loaded smooth as silk.

 

NyxxUK,

 

Do you use internal FPS limiter (via P3D menue) or external one (via NVI)?

 

Thanks

This explanation why locked FPS would be preferred over unlimited makes perfect sense giving the simulator be it FSX or P3D some headroom but in my case unlimited FPS has always given me the most smooth experience as well as the highest performance.

 

Can't explain why though, that's just the way it is over here and always been.

 

Hardware and OS differences makes it a maddening world doesn't it?   What works for one does not work for the other.   When Steve explained what locking frames does a while back in the original thread  I decided to lock them down to 33 with Trilinear buffering on and V-Sync enabled and that was the magic trick that finally made my sim stutter free with excellent texture loading even during bad weather at heavy airports.    If I run unlimited the entire sim universe becomes a frustrating place to live and I have to punch something.