'Elastic' movement

[ttjph]

On the subject of frame rate / performance / smoothness...

Last night I had a run in which I noticed persistent 'bouncing' of the scenery passing my cab, which hasn't been something that seems to have bothered me previously. Signals, signposts etc seemed to hesitate or lag slightly every second or so, then catch up with their 'correct' position. I've seen 'rubber banding' of AI trains before, but not this effect.

I was admittedly running right on the limit of the GPU's capacity, mostly seeing 99% usage (very occasionally 100%) to maintain a 30 fps lock with shadows and 2x2 SSAA enabled (although it was holding a solid 30 fps apart from the usual tile loading dips, much further apart than the 'bouncing' frequency, according to EVGA Precision X). The effect wasn't visible from the '2' view, where GPU usage dropped to 85-90%, although it was dark so perhaps not as obvious as it might be.

It was most obvious at low speeds, below about 20 mph; presumably at higher speeds objects were passing me too fast for my brain to be predicting their position with that level of accuracy.

I was using the JT 20 Advanced, in the supplied 'Wagon Repair' scenario on GWML. I don't think this loco is particularly scripted, not enough to cause major slowdowns?

I haven't tried any settings changes (shadows or AA off would be the first check!), but just wondered if others had observed the same thing and made any correlations...

[Timex]

That's funny, I have the same problem, I always thought it was something to do with my TrackIR.
I'm using a GTX980ti with fast sync enabled and have no lag or stuttering at all.
It seems to happen randomly, mine just bounces for a second or so, then returns to normal.
It's a like a shuddering effect to me, but I think we are talking about the same thing.

[ttjph]

Thinking about it more, I suspect it's the GPU dropping frames when it's close to its limit - it just doesn't update for one frame, so leaves the previous one displaying, but then renders the one after that fine.

Dropping my FPSLimit to 25 (from 30) fixes it, I think, but I'd be interested to know if there's anything else I could try (MaximumPreRenderedFrames in the nVidia settings?).

[holzroller]

Sounds like rubber banding that dogged the sim in it's early days. Noticed it myself a little lately. Probably because the sim is often at it's limits these days with the modern add-ons.