Hard landing issues

[Cbf]

Hardy,
Frame rate during flare is 22 FPS and the magenta bar vibrates.
Regards

[Hardy Heinlin]

That's not good. 22 frames average per second (ca. 50 ms per frame) would be fine if the rate were stable (no vibrations). But if it's so unstable, the frame durations may be something like ...

10 ms
99 ms
12 ms
120 ms
11 ms
155 ms

This affects all rate calculations in the simulation. They are all unstable.

Can you improve the computer performance?

(22 are just the counted frames per second; it doesn't say that all frames are equally long.)


Regards,

|-|ardy

[Cbf]

Hardy,
I will try to improve my computer performance.
I plan to replace it next year.
Since this issue, I performed more than 20 manual landings on other airfieds with a V/S beetween 200/300 FPM.
Thank you for your help and support.
Regards

[Jeroen Hoppenbrouwers]

Instead of replacing components, you can also try to figure out whether there are software items eating up the CPU capacity, or there are items overstressing your available memory. What does the Resource Monitor say if you don't run PSX? And if you run PSX?

[Hardy Heinlin]

You may also check the tips re graphic performance in the Aerowinx manual, page 76.

[Cbf]

Hi Hoppie,

Thanks for your help.

- Task management without PSX running


- Task management with PSX running


"Elevé" means High
"Faible" means Low

Regards

[Jeroen Hoppenbrouwers]

That load certainly should not lead to performance problems.

Hm. Did you look at more hidden programs, that are not "Applications" so don't show up in those lists, like virus scanners? There is something on your machine that irregularly eats resources away from PSX. Hardy's suggestion to look at exactly how the graphics are handled may also reveal something.


Hoppie

[Steve Hose]

Hi Cbf, further to Hardy & Jeroen's comments,

Can you please provide your basic PC specs? CPU type & speed, GPU model, RAM amount & windows version?

Regards, Steve.

[Hardy Heinlin]

Since this issue, I performed more than 20 manual landings on other airfieds with a V/S beetween 200/300 FPM.

Understood. But there's a great random factor in your system that influences the calculation of the terrain closure rate. This is independent of the smooth in-air flight progress. The terrain closure rate takes just a few frame durations into account to calcuate the average closure rate within a fraction of a second.

A simulation with variable frame rates, such as PSX, needs to measure the frame time passed after each frame update. The measured time is used for things that have to be changing at a specific rate (movements, temperature changes etc.). The sim adds a difference value to each changing object. The value is factored by the last frame duration. E.g. when the aircraft is flying at a certain speed, the sim may add 4 feet in each frame when the frame rate is 30, and may add 2 feet when the frame rate is 60. This keeps the aircraft speed stable when the frame rate varies. The logical problem is this: The frame duration of a frame is only known when the frame is over. If the last measured time is applied to the next frame, and that next frame actually has a duration that greatly differs from the last one, the calculated movement will make a jump, as the calculated rate disagrees with the actual computer power in this moment. If such hard fluctuations occur, the animation is no longer smooth. Normally, frame rates vary just slowly so that this problem will not occur.


Regards,

|-|ardy

[Cbf]

Hi Steve and Hardy,

This is the main computer on whitch I run PSX:

HDD 1To
During touchdown, FPS drops down to 22 (Unstable)
I know that my computer performance is below PSX requirements.
Unfortunately, I bought it before PSX release.

This is the second computer (laptop) on whitch I tried PSX:

HDD 1To
During touchdown, FPS drops down to 51 (Unstable)

Windows 10 20H2 installed on both computers.

Thanks for your support.

Regards

[Jeroen Hoppenbrouwers]

The CPU certainly should pull it.

4 GB main memory is on the low end for Windows 10. I had to upgrade my low-end box to 8 MB to get acceptable performance, but that is for changing programs, not for PSX. However your memory map suggests even 4 MB is fine.

Hoppie

[Steve Hose]

Hi Cbf, thanks for providing your PC specs.

Jeroen's right, while in theory the CPUs should be ok in most situations, the memory bandwidth somewhat limits you here, mainly due to the small memory cache for these cpus even though the total memory usage looks ok.

I'm afraid both PCs are showing their age and are going to struggle in certain situations that are data or calculation-intensive.

The i5 will do better than the A6 due to the higher turbo clock speed and lower memory latency due to a larger L2/L3 cache.

I'm afraid there's no easy way to circumvent a hardware bottleneck apart from... new hardware.

Good news is that you don't need to spend $1,000's on a new PC - a low to mid-spec PC (by 2021 standards) should do the job. Easier said than done in the current economic climate, I know.

Regards, Steve.

[Cbf]

Hi Steve,
Thanks for support and tips.
Regards