WinUAE unstable framerate since 3.4.0b1
 

Ok... today I got bored after 1 hour trying to adjust WinUAE CPU/Chipset settings to fix random micro-lags when scrolling in WHD games like Beast, Fantastic Dizzy AGA, Risky Woods... and so I started to test ALL previous WinUAE images 'till I've found something weird happened in-between 3.3.0 and 3.4.0b1 that made the fps counter (Miscellaneous > Native on-screen display) unstable: after 3.4.0b1 (included) up to current 4.5.0betas I've noticed fps can sometimes oscillate between 48-51 fps, while up to 3.3.0 it was rock solid 50fps ALL THE TIME and I couldn't spot a single micro-lag, never.

The games run in the same identical settings, with JIT off, D3D (or DX9-11 with modern WinUAE).

I can make a HDF for testing if you need Toni. If you'll just run this HDF with WinUAE 3.3.0 or 3.4.0b1+ you should see the subtle difference: micro-lags and fps fluctuation.
I'd really like to understand what happened with 3.4.0b1, because I love modern WinUAE improvements, but for sure (up to) WinUAE 3.3.0 still runs better (= constantly silky smoothly) for side/verical-scrolling games :(

I use a g-sync screen. Cfg used for tests in signature. Didn't change trying with 020, just for example... must be something with screen refresh/framerate buffering or something like that.

P.S.
3.4.0 beta thread has been deleted? I can't find it.

Could be related to your sound driver issues you talked about. I don't notice micro-stutter in newer WinUAE versions, fps are rock solid at 50 all the time.

No. I can reproduce it just swapping 3.3.0 with 3.4.0b1+ WinUAE.exe.
Same cfg file in signature: 3.3.0 = 50fps rock soldi counter (and I can't spot a single micro-hiccup), 3.4.0b1+ = 48-51fps randomly and some random microlag.

EDIT:
just found http://eab.abime.net/showpost.php?p=1107166&postcount=1 and changes with 3.4.0b1 were indeed huge, so now I have to guess what change could have been that introduced this minor yet annoying problem...

Just tried Beast WHDLoad v2.5 with the latest WinUAE. Freesync on/Vsync completely off@144Hz = smooth scrolling, stable fps. Lagless Vsync enabled @50Hz is the same.

I force no vsync since I have g-sync and I just use Display > Native: Fullscreen (nothing selected in vsync cycle-gadget).

I'm sure 70% users couldn't see what I'm talking about even when looking at my screen next to me, but I've very sensitive eyes for ANY sort of small micro-lag so with some suspects in mind I enabled Miscellaneous > Native on-screen display, and noticed there was actually some FPS random fluctuation starting with WinUAE 3.4.0b1 in the counter area... and this confirmed my picky eyes catch.

(Same here: 144Hz 1920x1080 display, with g-sync)

YouTube videos (please ignore ugly scrolling because was recorded at 60fps with NVidia GeForce Experience while the game was actually smoothly running at 50Hz/fps g-sync'ed):

3.3.0, stable 50fps (okay, there are just a pair of 49fps at the very beginning to be exact, but then is rock solid 50fps and never noticed micro-lags):
https://youtu.be/DTIb76nCdoQ

4.4.0, subtle fluctuating 50fps (with some micro-lags for very picky eyes):
https://youtu.be/J39EMZ6mqJU

Beast icon tooltypes (and WinUAE customized settings at launch):
SLAVE=ShadowOfTheBeast.slave
PRELOAD
QUITKEY=$59
Custom1=1
Custom2=0
ExecuteStartup=
ExecutePostDisk=uae-configuration cachesize 0 cpu_speed real waiting_blits true cpu_memory_cycle_exact true
Custom3=0
Custom4=1
(obviously I already tried with cycle_exact true, and all possible combinations and nothing changes. Same cfg on 3.3.0 runs flawlessly as you can see in the video above.)

P.S.
A good real 50fps recording program?

As i said: Freesync enabled and Vsync is completely off, in the graphics driver and WinUAE. No issues. Not sure what causes your issues. And believe me, i see ANY micro stutter too. This is annoying as hell. But for now WinUAE seems fine here on my side.

It's something in the emulator anyway... There are games like Fantastic Dizzy AGA WHD that show visible micro-stuttering for the side-scrolling vs parallax forest once again visible only with 3.4.0b1+
Setting JIT off, cycle-exact, cpu_compatible off etc. won't solve these random subtle micro-stutterings confirmed by fps counter, totally absent with 3.3.0 and before. Some chipset timings & syncs changes introduced this, at least for some hw (Win 10 2004, i7-8750h 6 cores 12threads + 32GB RAM + gtx 1070MP 8GB, 144Hz 1920x1080 g-sync here so it can't be a weak hw issue). Tested also with Audio: Disabled and won't change the issue. Also with GeForce Experience uninstalled nothing changes (nonsense anyway since 3.3.0 was working fine with it).

The master question is: Does it happen in most compatible A500 config too, via disk image load of the mentioned games (IPF original)?

It is almost certain I won't see anything wrong. (and HDF is nono: too many unknown variables anyway).

No default.uae. Don't change anything. A500 quickstart.

FPS jumping 49-51 is normal. In some version FPS counter become more accurate, originally it was averaged value which made it look like it was more stable. So this means nothing. (I don't think this was specifically mentioned in any changelog). Amiga 50Hz isn't exactly 50Hz but 49.94Hz.

3.4.0b1 does change PAL/NTSC FPS adj% behavior so you could try if ticking checkbox in right side of FPS adj. Display panel option changes anything. (Tick it and make sure text box value is exactly 50.000000)

EDIT: I have some other ideas too but I'll need to check some things first..

Of course it does... just tested Beast IPF in A500 Quickstart mode, and during intro I can see much more stable 50fps only with 3.3.0 and no (extra) micro-lags with g-sync. With 3.4.0b1+ up to 4.4.0 in my tests I see fps counter is much more fluctuating cyclically and I can notice random micro-stutter sometimes rarely.

Ok I suspected it could have just been a different rounding of the fps counter or others would have easily spotted this "issue"... but I'm quite sure since 3.4.0b1 it added some strange small micro-lags when playing previously silky smooth side-scrolling games at this point (on my HW at least...).

True. This happen via Freesnyc in other emulators too. No machine output exacly 50.00 oder 60.00Hz. Some emuators allows you to set it to integer fps though.

edit: Yep, WinUAE too.

Tested and even though looks better with 3.4.0b1 it won't completely hide those imperceptible random hesitations while scrolling compared to 3.3.0

In the meanwhile, 2 more videos Quickstart A500 and fps adj. default... As usual ignore bad sync to the 60fps of video recording and look how the 4.4.0 seems much more unstable (and in full screen with g-sync I can notice micro-stuttering like a sort "bad frame-pacing", compared to butter-smooth 3.3.0) but as Toni said this may be just because of different fps counter sensitivity. Anyway here are the videos:

3.3.0
https://www.youtube.com/watch?v=qDQ3tqBYcx8

4.4.0 (same as 3.4.0b1)
https://www.youtube.com/watch?v=HJ6a_DUHd8U

Can you check if you notice any difference with 3.3.0?
https://sourceforge.net/projects/win...4.zip/download

Not really. Looked a few minutes at the Shadow of the Beast Intro scroller, and the intro text scroller for level 1. Looks both very smooth without micro stutter. No matter what WinUAE version, 3.3.0 or recent.

Try also:
Risky Woods WHD (first long platform, move left-right)
Fantasy Dizzy AGA WHD (exit the house and move left-right on the first platform)
there is some minor stuttering in the scrolling parallax... absent with 3.3.0. Will test it on 2 more PCs this week but I'm quite sure there is some subtle stuttering for parallax scrolling games introduced => 3.4.0b1
It's barely visible, but it's there if you compare it with 3.3.0.

Risky Woods isn't a good choice. This game was never 100% smooth, judder happens on real Amigas too.

For Fantastic Dizzy: Looks pretty similar in 3.3 vs recent. Both versions shows a bit of micro stutter when you turn left-right fast and often enough. It's probably how it's coded. I've seen this in other games too, on my real Amiga.

Have you tested them on real A1200? I can't remember how did they run on my real Amiga 1200 + Blizzard 1260 in 2008...
Because with 3.3.0 and previous WinUAE versions Risky Woods and Fantastic Dizzy AGA's parallax is silky smooth and have no micro-stutter at all.

Perhaps it is best to find some demo with large long, 50Hz, horizontal or vertical scroller. Less unknown variables.

Pinball Dreams intro ...not very long though.