Well, I ran into VCACHE Windows protection error yesterday, after a BIOS upgrade on my Biostar X470 GTA/Ryzen 3900x/Vooodoo 3 PCI. Windows 95A, 98SE & Me all returned this error with no hardware change. As soon I reverted to the old BIOS all 9x systems worked great again...

So clearly something is breaking the compatibility with Windows 9x at BIOS level and it's not an actual hardware incompatibility...

Almost all consumer motherboards are running AMI BIOSes now. (Are there any new motherboards with Phoenix BIOS?)

The good part that there are official tools to fiddle with AMI BIOSes. AMIBCP to enable/disable menus and options and MMTool to insert/extract BIOS packages. Back to my motheboard, the old „PciBus” section had 79KB, but the latest version has only 75KB. Maybe I can reuse some old packages with a new BIOS release. In my case the reason for upgrade is Ryzen 5000 series compatibility.

Anyways, I'm almost sure that VCACHE error it has something to do with RAM, because I saw on a socket 1200 motherboard some legacy settings concerning the RAM operation. (unfortunately I don't have that board anymore)

Windows 9x has issues with more than 512MB or so of RAM in a machine.

You can limit available RAM seen by Windows by using Himemx and configuring for less RAM use (instead of using himem.sys), try some system.ini tweaks or use one of the patches available to address this issue .

Searching Vogons and Google for 512MB and Windows 98 should give you some useful info on the matter as this is has been known and documented for decades, so lots of testimonials and good info exist.

darry wrote on 2022-05-07, 15:38:

Windows 9x has issues with more than 512MB or so of RAM in a machine.
You can limit available RAM seen by Windows by using Himemx and configuring for less RAM use (instead of using himem.sys), try some system.ini tweaks or use one of the patches available to address this issue .

Yes, these tweaks is system.ini are working great when everything else is OK.

But on some newer motherboards I suspect that the BIOS itself may cause a Windows 9x protection error. I installed Windows 98SE on a Ryzen 3900X with 64GB (4x16) and Windows didn't care as long the available RAM was limited to 256MB in system.ini (MaxPhysPage=20000).

I blame it on BIOS because on my system AMD X470/Ryzen 3900x - all Windows 9X and NT systems are working great with the original and 2nd edition of the BIOS.

With the latest BIOS (06/2021) I get VCACHE error on Windows 95, 98 and Me.

Some newer motherboards came from the factory with this 9x unfriendly BIOS version (all BIOSes are made by AMI now for consumer boards) and people just assume that maybe the CPU, motherboard or memory are too new to run Windows 9x and give up... Actually might be just a stupid BIOS inconsistency regarding RAM or disk operation which trigger one of these situations:

If a real-mode driver and a protected-mode driver are in conflict. If the registry is damaged. If either the Win.com file or the […]
Show full quote

If a real-mode driver and a protected-mode driver are in conflict.
If the registry is damaged.
If either the Win.com file or the Command.com file are infected with a virus, or if either of the files are damaged.
If a protected-mode driver is loaded from the System.ini file and the driver is already initialized.
If there is a physical input/output (I/O) address conflict or a RAM address conflict.
If there are incorrect complementary metal oxide semiconductor (CMOS) settings for a built-in peripheral device (such as cache settings, CPU timing, hard disks, and so on).
If the Plug and Play feature of the computer’s basic input/output system (BIOS) isn’t working correctly.
If the computer contains a malfunctioning cache or malfunctioning memory.
If the computer’s motherboard isn’t working properly.

I limited ram to 512MB with my Athlon64 systemwith himemx, but I still get out of memory errors randomly in win98se just by opening normal file explorer windows and trying to copy files.

Baoran wrote on 2022-05-08, 18:59:

I limited ram to 512MB with my Athlon64 systemwith himemx, but I still get out of memory errors randomly in win98se just by opening normal file explorer windows and trying to copy files.

How about the original himem.sys? Right now, I run Windows 95/98/Me on a Ryzen3900x/32GB with no RAM issues. I just edited system.ini once and didn't think about RAM since then.

Good news! Now you can install Windows 98 even on Intel Raptor Lake configurations using a tiny patch named `cregfix`. (5 min video)

It looks like the solution was found by a guy "mintsuki" (probably him: https://github.com/mintsuki)

... after the page fault triggering the VCACHE issue, noticed that the cause of the page fault was a write to a non-writeable page while executing in ring 0. This behavior can either do nothing (if CR0.WP=0, which is the default setting outside of this OVMF/CSM version of legacy booting), or trigger a page fault if CR0.WP=1.

*A little more info on this blog.

The whole patch takes the form of a 33 bytes executable... which must be loaded in autoexec.bat

The rest of the Windows 98 installation is the same business as usually. On my test configuration (Asus H610 CSM/i3-13100F), everything was completely stable.

This is the assembly code:

1org 0x100
2 
3mov eax, 0x10
4mov cr0, eax
5 
6xor eax, eax
7mov cr2, eax
8mov cr3, eax
9mov cr4, eax
10 
11xor edx, edx
12mov ecx, 0xc0000080
13wrmsr
14 
15ret

How many of the device drivers are missing?

ElectroSoldier wrote on 2023-11-09, 07:30:

How many of the device drivers are missing?

For GPU there are PCI-E 9x compatible GPUs - NVIDIA 6000/7000 series and ATI x550/x700/x800/x850 series, or a PCI GPU, either via PCI slot on the mobo or through a PCI-E->PCI adapter
For USB Keyboard - CSM and Legacy USB options in UEFI take care of this.
For USB Mouse - you can use LMOUSE.DRV (renamed as MOUSE.DRV) from Win3.1 to get around the jumpy mouse issue. Or use a PCI-E x1 USB 2.0 card (which I use) and connect mouse there, or use a PS/2 Mouse.
For Audio - either a PCI sound card, the aliexpress c-media cmi8738 pci-e sound cards, a USB Sound Card (which I use), or the extremely janky and not recommended fan made hd audio driver for 3.1
For AHCI - 9x by default will use DOS mode disk access, to improve it, use the AHCI driver from the late R. Loew
For too much memory issue - PATCHMEM with /M switch from R. Loew (also takes care of any VCACHE issues, my vcache section in SYSTEM.INI is empty)
If the system hangs on the bootscreen - HIMEMX is required.
For LAN - depends on the motherboard, if Realtek chip - high changes that the DOS/NDIS2 drivers will work. If Intel - like in my case - not possible - too new of a chip. Older Intel chips might work with the DOS/NDIS2 drivers. There are of course options of using a PCI-E/PCI NICs. Are there any USB ethernet card compatible with 9x?

Rebooting will not work, but shutting down and using Ctrl+Alt+Del at the Safe to shutdown screen is an easy workaround.

I do not care about all the other devices with yellow question marks in the Device Manager, they are not required for operation.

Overall it's not as scary as you think, and not that unstable, 9x is always unstable, even on 440BX 😁

MrMateczko wrote on 2023-11-14, 14:13:

Rebooting will not work, but shutting down and using Ctrl+Alt+Del at the Safe to shutdown screen is an easy workaround.

It think this is an issue with your specific build/software, because I can restart and shutdown normally on my configuration: H610/i3-13100F/Radeon X300. BTW, Windows 95A is working smooth with this patch.

What nVidia drivers are you using? Can you leave a link? I use "Tweaked Unofficial NVIDIA Display Driver 82.69" (MDGx) but I get mixed results....

Are the devices without drives disabled in the hardware profile?

@MrMateczko
@ OMORES

Lmouse useful information, I will try it. A PS2 mouse works, but a USB one wouldn't hurt, the latter is ok under DOS, I also have a bug under Win98.
USB keyboard: indeed the legacy BIOS handles it well.
SATA AHCI: works fine with Loew drivers.
QFX3450/3500-7900GS-6800GS: also ok with the modded NV driver.
32GB RAM : Loew memdriver, no problem.
Audio: PCIe->PCI/SB060 - DOS/SBEMU - Win98: native driver from the CD.
VCache: it didn't appear for me, I have an old BIOS on the B450, but CRegfix may be useful for others.

@OMORES
I use these drivers http://web.archive.org/web/20150602212418/htt … iles/NV8269.ZIP
Also need the NVCORE.VXD shutdown fix from R. Loew's package of NVIDIA fixes. My 7900 GTX does have the 512MB VRAM BIOS fix applied as well.
Is PC Archive your second channel?

@ElectroSoldier
No, I do not disable anything or use hardware profiles, no need to do so.

@DarthSun
I used to have Ryzen 5 3600 on ROG STRIX B450-I GAMING motherboard in 2020/2021 and 98SE worked there fine
It wasn't until the 12th gen/ryzen 5000/am5/newer uefi bioses that vcache error issue got widespread.

It wasn't until the 12th gen/ryzen 5000/am5/newer uefi bioses that vcache error issue got widespread.

Yes, this is typical, but some people have the problem even on B450 motherboards that are later than mine.