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Windows 95 2.1GHz CPU Limit BROKEN!

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***UPDATED 06-10-2013***

I have managed to fix the 2.1GHz CPU limit of Windows 95. :o

Completely with updates from Microsoft... when they claimed there was no fix for this.

Here's a link to the MSKB article on this issue.

Q312108 - Windows Protection Error in NDIS With a CPU That Is Faster Than 2.1 GHz


Version 3.0 Released 06-10-2013

New or otherwise significant in this version:

- Version 3.0 can be used on all Windows 95 versions. (RTM\OSR2) (95\95A\95B\95C)

- Version 3.0 addresses specific issues with and better supports Windows 95 RTM. (95\95A)

- Version 3.0 makes the proper registry entries that would be made if AMDK6UPD.EXE and the other updates were installed under Windows 95.

- Version 3.0 includes a Processor-specific HotFix for Windows 95B OSR2. It is not needed on other versions of 95.

- Version 3.0 no longer includes or mandates the installation of DUN14-95.EXE. Still "recommended."

- Version 3.0 can be installed before or after the "Windows Protection Error in IOS" has been displayed. (Before is still the preferred method.)

- Version 3.0 can patch a Windows 95 installation in directories other than C:\WINDOWS.

- Version 3.0 includes further updated versions of some system files contained in the AMDK6UPD.EXE patch, rendering AMDK6UPD.EXE obsolete.

- Version 3.0 includes PTCHCDFS, a free update by Rudolph Loew that corrects the displayed size of DVD media.


The README.TXT from FIX95CPU_V3_FINAL.ZIP, provides a detailed overview of this project, this issues it addresses, and the instructions for getting it to work. I will post it here:


Windows 95 High-Speed Processor Support v. 3.0 By LoneCrusader


README.TXT - Self Explanatory.

FIX95CPU.EXE - Self-Extracting Bootable Floppy Disk image.

FIX95CPU.IMA - A standard image of the Bootable Floppy.

(For Virtual Machines.)

FIX95CPU.ISO - A standard Bootable CD image.

(For Virtual Machines, or systems without a floppy drive.)

VMM2XUPD.EXE - HotFix with updated VMM.VXD's for Windows 95 B OSR2.

(Install in Windows 95 B OSR2 after Setup has completed.)



The first section of this README will explain the issues addressed

by this patch. If you are familiar with these issues, you may skip to

the second section for step-by-step instructions.


Windows 95 has two specific errors when dealing with processors

with speeds higher than 350 MHz. With a little patience however,

both of these errors are fixable.

The first error occurs with processors greater than 350 MHz.

Microsoft released a patch for this error, AMDK6UPD.EXE. This

patch IS NOT just for AMD processors. It will work for Intel

Pentium 4 processors as well. The problem with Microsoft's patch

is that it must be run from within Windows. When your system

encounters this error, you will not be able to boot into Windows.

This error will be displayed on the first reboot during the

installation process.

Here is the text of the error:

While initializing device IOS:

Windows Protection Error. You need to restart your computer.

The only way to fix this error is to manually install the files

contained in the Microsoft AMDK6UPD.EXE patch. This package automates

the process for you, so I will not go into further detail on that

issue here.

The second error occurs with processors greater than 2.1 GHz.

This problem also affected Windows 98 (First Edition), and Microsoft

issued a HotFix for Windows 98, but not for Windows 95. According to

Microsoft, there is no fix for this problem in Windows 95... WRONG!

This error is very similar to the previous one, and it will also be

displayed on the first reboot of the install process, after you have

fixed the previous error.

Here is the text of the error:

While initializing device NDIS:

Windows Protection Error. You need to restart your computer.

This error is corrected by an updated file contained in the DUN14-95.EXE

Dial-Up Networking 1.4 Update for Windows 95. This package automates

the process for you, so I will not go into further detail on that

issue here.


This update renders the AMDK6UPD.EXE patch OBSOLETE, as it

installs newer versions of some system files contained within

AMDK6UPD.EXE. While the main purpose of this update is to

enable the use of High-Speed Processors, I decided to include

any available newer versions of the system files already

contained in this patch.

List of Issues (MSKB Articles) FIXED by this update:

Q192841 - Difficulties Using AMD K6-2 or Athlon Central Processing Unit

Q234259 - Revision to AMD K6-2/350 Central Processing Unit Update

Q312108 - Windows Protection Error in NDIS with CPU Faster Than 2.1 GHz

Q231942 - Cannot Undock Notebook Computer with LS-120 Removable Drive

Q175629 - Large IDE Hard Disk May Run In Compatibility Mode

Q274175 - Error Opening/Copying File/Folder Eight Levels Deep on CD-ROM

Q159153 - Error Messages While Backing Up to Some Floppy Disk Drives

This update also includes a patched version of CDFS.VXD using PTCHCDFS,

a free update by Rudolph Loew (rloew) to fix the incorrect size value

(1.99GB) reported by Windows 9X for DVD's.

A separate bug exists in Windows 95 RTM/A that causes DVD sizes over

4GB to not have their byte counts displayed properly, showing "---"

instead, but the correct total size of the DVD will still be displayed.

Installing other update packages for Windows 95 RTM/A may yield a

solution to this, but has not been tested.

Also included in this version is a HotFix, VMM2XUPD.EXE, which installs

the latest version of VMM.VXD for Windows 95 B OSR2. This package should

be installed when Windows 95 B OSR2 Setup has completed. This update will

not run on Windows 95 RTM/A and is not required on Windows 95 C OSR2.5.

Credits & Other Information:

Rudolph Loew has also created a free UDF filesystem driver for reading

UDF formatted CD's/DVD's in Windows 95. It can be obtained from his site

at: http://rloew1.no-ip.com or mirror at: http://rloew.limewebs.com

Many thanks go out to Rudolph Loew for his assistance with this project!

Credit also goes to Petr at MSFN for providing patched files for 95 RTM.

And finally credit to Queue at MSFN for creating the ANSI Windows Logo.

For further information and updates, visit this topic at MSFN Forums:


This package makes use of the General Replace (GR) text replace utility

created by Andrew Sharrad, which can be found at:



Follow these Instructions to get Windows 95 up and running.

You Will Need:

Blank Floppy Disk or Blank CD

Files Contained In FIX95CPU.ZIP


If your system does not have a floppy drive, the FIX95CPU.ISO

Bootable CD image in this package can be used (with Nero or

a similar CD burning program) to create a bootable CD that can

be used instead of a floppy.


These instructions and the FIX95CPU installer assume that

you are installing Windows 95 to C:\ Drive, however you can

use a directory other than C:\WINDOWS.

1. On another computer, use the self-extracting Floppy Disk image

(FIX95CPU.EXE) or the Bootable CD image (FIX95CPU.ISO)

provided in FIX95CPU.ZIP to create a custom Boot Disk

that will contain this patch.

2. Prepare your system and run Windows 95 Setup.

3. When Windows 95 asks you to Restart, insert the Boot Disk or

Boot CD that you created with the enclosed image, and click

Finish. You should have the Boot Disk or Boot CD inserted

BEFORE Windows Setup continues and the IOS error is displayed

in order to speed up the boot process by combining .VXD's

with WININIT.EXE, but this version allows for installation

after the IOS error has been displayed.

4. The Boot Disk will start your computer in DOS mode. Press SPACE and

you will be given an opportunity to view this README file.

Choose Y or N, and then all you need to do is press SPACE again

to bring up the next page of the README, or to apply the patch.

The program will output its actions to the screen so you can see

what is being done.

Pressing CTRL-C at any time will terminate the FIX95CPU program.

5. When finished, press SPACE to reboot your system, then remove the

Boot Disk or Boot CD so Windows 95 Setup can continue normally.

If you are installing Windows 95 RTM/A or C OSR2.5, you are finished.

For Windows 95 B OSR2 ONLY:

6. When Setup is complete and your Windows Desktop loads, run

VMM2XUPD.EXE to update VMM.VXD to the latest version, and you

will be prompted to restart.

This update is not necessary on Windows 95 C OSR2.5.

If you have Windows 95 RTM/A or C OSR2.5, skip this step.

The VMM2XUPD.EXE will not install on Windows 95 RTM/A.

The VMM2XUPD.EXE update addresses the following issue:

Q179897 - Memory Management Problems with Pentium Processors

You have successfully completed all steps.

Install the drivers for your hardware and your programs.

Have Fun!



1. If you plan to install the Microsoft USB Supplement to Windows

95 OSR2 (USBSUPP.EXE), be aware that this update will sometimes

overwrite the file C:\WINDOWS\SYSTEM\VMM32\NTKERN.VXD without

prompting you to keep the newer file already installed by this

patch. If this occurs, the following error will be displayed:

While initializing device NTKERN:

Windows Protection Error. You need to restart your computer.

This can be corrected by recopying the NTKERN.VXD contained in

this patch to your system.












This software brought to you by Conner McCoy (LoneCrusader) with

assistance from Rudolph Loew (rloew).



***UPDATE 12-18-2010***

Slipstreaming instructions added Here.

Microsoft issued a Hotfix for this problem in Windows 98 FE. It contains an updated version of NDIS.VXD

that only works in 98. Apparently they forgot (intentionally? :ph34r: ) or never realized that the

updated version of NDIS.VXD in the DUN14-95 update solves this problem as well.

Of course this isn't going to do you much good if Windows 95 drivers do not exist for your hardware. If

you have version 3.40.1001 of the Intel Chipset INF Installation Utility, it still contains 95 Drivers

covering the 845 chipset, which I know was used on motherboards supporting up to 3.06GHz processors.

The system used for this test:


Motherboard: Soyo SY-P4I845PE

Processor: 3.06GHz Intel Pentium 4 w/ Hyper Threading

Memory: 512MB Kingston DDR 333

Video Card: ATI Radeon 8500 LE 128MB

Audio & LAN: Onboard


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Nice. But why are you installing the AMDK6 patch twice? (once manually, once automatically)

**EDIT 2-10-2010**

It does not appear to be necessary to do this. I have changed the instructions to reflect that.

win95 working fine!

AMD Atlhon 64 processor 4000+ 2.40 ghz

mobo asus av8

512 ram

thanks LoneCrusader :thumbup


Congrats, I'm glad someone else is interested and can confirm my results. :thumbup

I might have to try my hand at making a "patch" that would automate some of this if people are interested.

Now if only RLoew's RAM patch worked in 95 :whistle:

Edited by LoneCrusader
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Can you just copy ndis.vxd at the same time the files from the K6-2 patch are copied over?

I'd test it, but I don't have access to a PC with a CPU over 2.1 GHz to run in Virtual PC.

**EDIT 2-10-2010**

Incorrect information removed.

This is possible if you allow the IOS error to be displayed and allow VMM32.VXD to be compressed before copying the K62 patch + NIDS.VXD. (See instructions above.)

I strongly recommend installing DUN14-95.EXE normally when Setup is complete however, it contains several other updated system files related to Networking, whether you use Dial-Up Internet or not.

Great work, LoneCrusader! :thumbup

This thread is now added to the Important "Stickified" [Pinned] 95/98/98 SE/ME Topics.

Wow :w00t:

I never thought I would be worthy of that list. Thanks guys! :thumbup

Edited by LoneCrusader
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I've uploaded the file here [2.78 MB]:


[re-ZIPped using 7-zip, "shaved off" a few more bytes = smaller file size. ;)]


Thanks MDGx :thumbup

@everyone else:

I'm open to suggestions on how this "patch" might be improved, If some of you get to test it, please give me some feedback.

Good Luck!

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Nice. But .... (once manually, once automatically)

"Nice" that's all you have to say Ben?

I expected you to be more enthousiastic.... :unsure:

Well, I'm not affected by the 2.1 Ghz limitation, and don't plan on getting a faster processor or another computer any timle soon.

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Hi LoneCrusader, MDGx, Dencorso

I built a Slipstreamer to implement this project automatically installing Windows 95.

"Folders iosubsys and vmm32"; Moved to CPUFIX.CAB all new files (*. VXD, *. PDR) and extracted from this, not the original Win95 .CAB's

"Ndis.vxd"; the script extracts the "net.inf" and changes, and "Ndis.vxd" is not copied during the installation, is also removed part of the REGISTRY, no more error: "Ndis.vxd missing...". :rolleyes:

PS: DUP14-95 correct these changes after ...

"Client for NetWare Networks"; With a change in the "Netcli.inf", let the installation proceed without disabling this service...

"DUP14-95.exe"; Added in the Session "RunOnce" from "SETUPC.INF" (HKLM,Software\Microsoft\Windows\CurrentVersion\Run,Dun14-95,"c:\win95\Dun14-95.exe /q")

DUP14-95.exe is installed in unattended mode with Windows 95 Setup :thumbup

will install the Windows 95 now? :sneaky:

prepare the hard disk

copy the "WIN95" folder from Windows 95 cdrom to "C:\"

copy CPUFIX.BAT, CPUFIX.CAB and DUP14-95.exe to the "C:\WIN95"

From the "c:\WIN95" type "cpufix.bat" and wait for the complete installation

Yes, restart






Download CPUFIX: http://www.sendspace.com/file/enw21a

Download DUN14-95: http://download.microsoft.com/download/win...us/dun14-95.exe

give me some feedback

My System

Windows 95 4.00.950 B (Portuguese Brazil)

AMD Atlhon 64 Processor 4000+ 2.41GHZ

Mobo Asus A8v Deluxe

512 MB

Gforce 5200

Edited by BeatZero
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I don't have Win95 installed anymore so I can't actually test your scripts, but I took a look at the BAT file, and looks like it should do what it claims.

Good work.

Pls let me know if you want this new version uploaded at my site, eventually to replace the older one.

Until then, the new one is here [2.54 MB]:


(also contains DUN14-95.EXE + your old README.txt).

You just need to update your ReadMe text file now. ;)


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