Is that Win98SE ? Which games ? and what resolutions are you trying to play at ? Mixing VXD and WDM drivers can cause issues. If the Turtle Beach is VXD and the newer Video driver is WDM it could part of the issue but could also be something else...
Only other thing is your video driver is quite old even for Win9x: https://www.nvidia.com/en-gb/drivers/win9x-archive/ and this is the last one: https://www.nvidia.com/en-us/drivers/win9x-8198/

Horun wrote on 2021-08-16, 00:47:

Mixing VXD and WDM drivers can cause issues. If the Turtle Beach is VXD and the newer Video driver is WDM it could part of the issue but could also be something else...

Mixing VXD and WDM drivers could have never been the issues on Win98/SE/ME. It is a perfectly legit use case for different hardware to use different driver models supported by the OS, but not both at the same time by the same hardware.

It's possible that the sound card is using WDM instead of VXD. Some WDM audio drivers have issues that are not present on their VXD counterparts on Windows 9x.

can I play the bad guy and blame it all on the P4? Have you checked your mounting pressure with that CPU cooler on the CPU? your problems sound a lot like thermal throttling to me. Could also be that you installed unofficial SP3 that thing is trash.

Don't use the unofficial SP3 patch it's garbage.

An overheating CPU or GPU could perhaps explain it, depending on the game. You can also try a later driver version.

kjliew wrote on 2021-08-16, 01:40:

Horun wrote on 2021-08-16, 00:47:

Mixing VXD and WDM drivers can cause issues. If the Turtle Beach is VXD and the newer Video driver is WDM it could part of the issue but could also be something else...

Mixing VXD and WDM drivers could have never been the issues on Win98/SE/ME. It is a perfectly legit use case for different hardware to use different driver models supported by the OS, but not both at the same time by the same hardware.

I've gone much further than this back then. 😁
On Win 9x, I've mixed in Windows 3.x drivers, both 16-Bit *.DRV and 32-Bit *.386 (early VXD) types.

What kind of monitor are you using?
Are you using DVI or VGA?
I had an issue where I used a flatscreen monitor over VGA, where the gpu sent out 75Hz signals, while the monitor was only 60 Hz (but did accept 75 Hz input).
This caused a big amount of stuttering, manually adjusting the monitor settings in Windows 98 to 60 Hz or using DVI fixed the issue for me.

I had a similar issue with my Athlon System. Could solve it by disabling the network card (intel PCI). Afterwards i switched out the network card. Cannot explain it or figure out the root cause.

Okay guys, I gave up with troubleshooting the issue. I'm pretty sure that the cause of the issue was something i had installed with the Unofficial SP3. I have noticed this same issue on a p3 build with a via chipset and i thought it was the issue. I'm not going to be using the USP3 anymore with my builds. I cant say for sure what package caused this issue. I did a clean install last night and configured all my hardware, and the system is running smooth now. I'm going to also do a clean install on the p3 build with the via chipset and I'm going to delete my copies of the USP3 from my server so i never run into this issue again.

Great ! Glad you figured it out. Thought maybe it was a driver issue and now will never install the U-SP3 !

I personally prefer to use SP2 instead of SP3 for Windows 98.
It already contains all patches for 98 and I don't need any of the newer functions SP3 provides.
Haven't had any problems with that version so far.

Limpem wrote on 2021-08-17, 07:16:

I personally prefer to use SP2 instead of SP3 for Windows 98.
It already contains all patches for 98 and I don't need any of the newer functions SP3 provides.
Haven't had any problems with that version so far.

+1

SP2 works without issues..

PC-Engineer wrote on 2021-08-16, 12:39:

I had a similar issue with my Athlon System. Could solve it by disabling the network card (intel PCI). Afterwards i switched out the network card. Cannot explain it or figure out the root cause.

Sorry to bump an old post, but I figured something out and thought I would share if anyone else has this issue in the future. I was messing around with a p4 3ghz intel 865 chipset. I had a Radeon x850 pro installed and I was noticing the same stuttering issue that I had ran into before.
It was like clockwork every 3-4 seconds every 3d game or benchmark I was playing would just stutter for a few split seconds and then go back to normal. I noticed fps dipping hard when I was in a game with fraps on. I knew the specs of that machine was crazy high, so there should be no reason for the stutter. I removed the Radeon x850 pro and installed a GeForce fx5700ve 256mb. The stutter was still there. On the win98se desktop I was just messing around and started spinning an opened explorer window in circles and that too was getting that weird stutter.
I then loaded up process explorer and watched the services and noticed 1 of the services would jump to around 50% CPU usage for a couple seconds and then back to 0%. It would do this over and over. The process was ssdpsrv.exe.
I looked into it, and it seems it's a UPnP process. Not sure what I had installed to install or enable that service but as soon as I killed the process the stutter was gone. I disabled that service from startup and the system has been rocking full speed for the past couple days.
I remembered your reply about disabling the network card and that fixed your issue. Maybe you too had UPnP enabled. I read that ICS had a security bug back in the day and it was recommended to disable ICS. It may be some network setting that enables this process.