Audio Glitches and Awkward Video Speed

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unreal9010
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Re: Audio Glitches and Awkward Video Speed

Post by unreal9010 »

Navigate to the Video section of the PCem's menu which is right below its status bar. Here you will see an entry called Render driver. Try different render drivers to see which one works best for you.
Another thing to try: in your Windows Task Manager navigate to the Details tab. Look for the pcem entry and right click on it. Pick "set affinity" and let only one or two CPEs be ticked (preferably the upper ones from the list).
As mentioned before, changing the SMT setting might do the trick as well.
TonyTran
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Re: Audio Glitches and Awkward Video Speed

Post by TonyTran »

You mean when SMT is on, it negatively affects performance?
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unreal9010
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Re: Audio Glitches and Awkward Video Speed

Post by unreal9010 »

In some cases when using certain applications, it might.
TonyTran
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Re: Audio Glitches and Awkward Video Speed

Post by TonyTran »

So do I have to turn SMT off when using PCEM?
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unreal9010
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Re: Audio Glitches and Awkward Video Speed

Post by unreal9010 »

Depending on how it affects the performance of PCem. If negatively, it might be better to leave it turned off when using PCem.
TonyTran
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Re: Audio Glitches and Awkward Video Speed

Post by TonyTran »

Would a different motherboard (for emulated systems) impact performance as well?
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unreal9010
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Re: Audio Glitches and Awkward Video Speed

Post by unreal9010 »

It might, it might not. At best probably around 15-20% which is about a real life difference between the low and the top quality boards, however, none of the boards currently emulated is a low quality one.
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unreal9010
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Re: Audio Glitches and Awkward Video Speed

Post by unreal9010 »

I was talking about the virtual machine not the PCem performance. I didn't notice any particular difference when trying out emulation of different Socket 7 boards.
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Arjen42
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Re: Audio Glitches and Awkward Video Speed

Post by Arjen42 »

Difference between emulated machines is closer than one might expect. Think of PCem as an generic PC emulator that has some tweaks to be compatible with different BIOS's.
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unreal9010
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Re: Audio Glitches and Awkward Video Speed

Post by unreal9010 »

It's noteworthy that there is no general formula how different configurations will behave under PCem on a host computer.
The best thing to do is to try different configurations and then go with the one that works best, making sure that selected virtual machine configuration is not too demanding for the CPU of the host computer.
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unreal9010
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Re: Audio Glitches and Awkward Video Speed

Post by unreal9010 »

Another reason for performance bottlenecks could be the use of real physical discs such as CDs and floppies. Always make virtual copies of these and then load them under PCem. There's free software available that allows you to make virtual images of CDs/floppies you want to use with PCem.
TonyTran
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Re: Audio Glitches and Awkward Video Speed

Post by TonyTran »

unreal9010 wrote: Sun 30 Jan, 2022 8:17 pm Navigate to the Video section of the PCem's menu which is right below its status bar. Here you will see an entry called Render driver. Try different render drivers to see which one works best for you.
Another thing to try: in your Windows Task Manager navigate to the Details tab. Look for the pcem entry and right click on it. Pick "set affinity" and let only one or two CPEs be ticked (preferably the upper ones from the list).
As mentioned before, changing the SMT setting might do the trick as well.
I selected only the first two CPEs, but they made the CPU on the emulated machine run even slower. Are there any CPEs that can optimize the emulated CPU performance to run smoothly when only they are ticked?
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unreal9010
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Re: Audio Glitches and Awkward Video Speed

Post by unreal9010 »

Try a different combination of CPEs. For example CPE 0 and CPE 2. I do hope that none of the software you are trying to run with PCem is located on physical media (e.g. CDs).
TonyTran
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Re: Audio Glitches and Awkward Video Speed

Post by TonyTran »

Maybe Windows 98 more demanding than Windows 95. I might consider turning off SMT, but does Windows 11 require SMT?
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unreal9010
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Re: Audio Glitches and Awkward Video Speed

Post by unreal9010 »

Windows 98 is more demanding than Windows 95, though not significantly. As far as I know, Windows 11 does not require SMT.
TonyTran
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Re: Audio Glitches and Awkward Video Speed

Post by TonyTran »

I can't find the option to disable SMT in the BIOS of my Dell Inspiron 15 laptop.
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unreal9010
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Re: Audio Glitches and Awkward Video Speed

Post by unreal9010 »

Consult your manual.
TonyTran
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Re: Audio Glitches and Awkward Video Speed

Post by TonyTran »

I could have gone with the 486 in place of the Pentium to attempt to reduce the load on the host CPU, but the BIOS of each 486 motherboard emulated by PCEM didn't show/detect the CD drive.
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unreal9010
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Re: Audio Glitches and Awkward Video Speed

Post by unreal9010 »

Go with Pentium 90 for the start. If the things are stable, slowly increase the speed of an emulated CPU.
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CryptidWorks
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Re: Audio Glitches and Awkward Video Speed

Post by CryptidWorks »

unreal9010 wrote: Sun 30 Jan, 2022 8:17 pm Navigate to the Video section of the PCem's menu which is right below its status bar. Here you will see an entry called Render driver. Try different render drivers to see which one works best for you.
Another thing to try: in your Windows Task Manager navigate to the Details tab. Look for the pcem entry and right click on it. Pick "set affinity" and let only one or two CPEs be ticked (preferably the upper ones from the list).
As mentioned before, changing the SMT setting might do the trick as well.
Please do not tell people to do this because:

A)Windows arranges threads in pairs so choosing sequential threads limits physical core usage. The best trick is to disable SMT by giving it only either all the odd or all the even numbered threads.

B)PCEM can use up to five threads, one for CPU emulation and four for Voodoo emulation
eddman
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Re: Audio Glitches and Awkward Video Speed

Post by eddman »

TonyTran wrote: Tue 18 Jan, 2022 10:57 pm My CPU is AMD Ryzen 7 5700U with Radeon Graphics @ 1.80 GHz. I have a RAM of 16.0 GB and my OS is Windows 11. I have a laptop.
That CPU should be able to emulate Pentium MMX 166-200, maybe even 233. Make sure it's plugged to the charger.

Don't mess with threads and SMT just yet. Run PCem and then monitor the CPU clock speed with CPU-Z (Task Manager isn't accurate enough for that).

EDIT: Perhaps something like MSI Afterburner could be better, since it can show the CPU speed as a graph and for each core.
CryptidWorks wrote: Fri 11 Feb, 2022 6:46 am B)PCEM can use up to five threads, one for CPU emulation and four for Voodoo emulation
6 threads: https://pcem-emulator.co.uk/phpBB3/view ... 101#p15101
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unreal9010
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Re: Audio Glitches and Awkward Video Speed

Post by unreal9010 »

CryptidWorks wrote: Fri 11 Feb, 2022 6:46 am
unreal9010 wrote: Sun 30 Jan, 2022 8:17 pm Navigate to the Video section of the PCem's menu which is right below its status bar. Here you will see an entry called Render driver. Try different render drivers to see which one works best for you.
Another thing to try: in your Windows Task Manager navigate to the Details tab. Look for the pcem entry and right click on it. Pick "set affinity" and let only one or two CPEs be ticked (preferably the upper ones from the list).
As mentioned before, changing the SMT setting might do the trick as well.
Please do not tell people to do this because:

A)Windows arranges threads in pairs so choosing sequential threads limits physical core usage. The best trick is to disable SMT by giving it only either all the odd or all the even numbered threads.

B)PCEM can use up to five threads, one for CPU emulation and four for Voodoo emulation
There is no guarantee that toying with core affinity settings will actually be of any help. It may be of some use in certain situations, particularly when running an old app that uses only one CPU thread. Running PCem with Voodoo 3 as a virtual GPU (especially when using 4 threads) might make things even worse.
There is also no particular rule how PCem will behave on different configurations. The best thing to do is to test and try different settings from SMT, power plans, core affinity etc and then go with the one that works best.
As far as I've seen on Youtube, people with newer Intel processors got the best performance results, particularly when emulating Pentium II processors.
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unreal9010
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Re: Audio Glitches and Awkward Video Speed

Post by unreal9010 »

eddman wrote: Fri 11 Feb, 2022 9:28 am
TonyTran wrote: Tue 18 Jan, 2022 10:57 pm My CPU is AMD Ryzen 7 5700U with Radeon Graphics @ 1.80 GHz. I have a RAM of 16.0 GB and my OS is Windows 11. I have a laptop.
That CPU should be able to emulate Pentium MMX 166-200, maybe even 233. Make sure it's plugged to the charger.
That CPU shoud be at least 10% faster (in theory, though) than mine (i7 6700). I can emulate a number of games at 100% under Pentium II 233, some even under 333. Either something is bottlenecking that particular CPU or AMD is just being AMD. Don't get me wrong, I've got nothing against AMD. I hate fanboyism. If any of their processors work well with the PCem, then even better. However, I owned at least two AMD CPUs to date (one of them being Duron and the other one Phenom II X4) and the only thing they both truly excelled at was overheating at stock speed. As far as emulation is concerned, they were both terrible performers compared to equally priced Intel processors at the time.
My general advice: If emulating older systems is a top priority for you, then go with Intel.
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unreal9010
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Re: Audio Glitches and Awkward Video Speed

Post by unreal9010 »

Here is an example how PCem runs with i7 10700KF processor. The particular CPU has a Passmark ST rating of 3,054.
https://www.youtube.com/watch?v=6FVgTlg8iNA
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Trackah123
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Re: Audio Glitches and Awkward Video Speed

Post by Trackah123 »

I have similar issues, however i tried some things that did make some difference.

First of all my real system specs for comparison are :

PSU : Corsair RM850x
Mobo : Asus Strix Z270H Gaming (socket 1151)
CPU : Intel i7 7700k @ 4.2Ghz
RAM : Kingston HyperX 16GB DDR3@2133Mhz
GPU : Asus Strix Nvidia Geforce 2070 RTX
SoundCard : Creative Sound Blaster E1
SSD : Samsung SSD 970 Evo Plus (PCIe NVMe)
Monitor : IIyama ProLite 32" 4k

Gfx bus-speeds : Some older games work better with different graphics card speeds, for example in DOS 6.22 i had some really old games that run fine in 8-bit or slow/fast 16-bit modes, in Windows 98SE with NeedForSpeed 2 Fast VLB/PCI setting seemed to work best.

Renderers : OpenGL 3.0 Renderer seems to work best and also lock to 60FPS? the other renderers are unlocked and peak out to 500fps on the pcem status page? even with forced vsync in pcem and in my nvidia control panel, did not seem to make a difference and the fps stayed unlocked.

Soundcards : Now the weird part, for some reason Sound Blaster AWE32 gives less stutter and glitches compared to other cards like Sound Blaster 16 or even PCI 128.
On AWE32 with a buffer of around 100-200 i get good results, however with the other ones i had to put it on 400 to even get close to a decent sound.

I could run a virtual system with Gigabyte GA-686BX 450 - 500mhz with almost no issues. I hope this helps.

I'm not technical at all when it comes to programming so forgive me if i say something silly.

1: Would Vulkan Api support make a difference compared to OpenGL 3.0 regarding performance?
2: I'm not sure if this emulator uses DirectSound or OpenAL, but i wonder if other api's (WASAPI, OpenAL, PortAudio, Asio etc) would make a difference in "sound performance"?
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Trackah123
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Re: Audio Glitches and Awkward Video Speed

Post by Trackah123 »

Small update on 3DFX Games, seems to require a bit of different configuration in order to make it work properly.

CPU Speed in Emulator sometimes have to be lowered in order to reduce stuttering, starting from 166mhz ~ 200mhz seems to work decent.
Render threads on the Voodoo settings should be either 1 or 2, 4 seems to be glitching (NFS2 SE Main Menu for example). Still using "Fast VLB/PCI".
OpenGL 3.0 Renderer didn't work well for 3DFX stuff (audio hiccups), any other renderer works fine.
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