1.5 GHz too fast for Windows 95?

[CamTron]

I had an extra 160 GB hard drive lying around, so I decided to install Windows 95 (original RTM version) on my Dell Dimension 4300 just for kicks. This computer has a 1.5 GHz Pentium 4 (Willamette), and 512 GB of PC133 RAM. I was able to install Windows 95 okay, but when I booted it up, I got the dreaded "Windows protection error. You need to restart your computer." message. However, my BIOS has a way to lower the CPU speed, so I changed that setting from "normal" to "compatible", and it was able to boot Windows 95. The only problem is that it runs very slow like that, and I'd like to be able to use the full speed of the CPU. I've installed Windows 95 in virtual machines on 3.4 GHz processors, so I'm not sure why it has trouble with a 1.5 GHz Pentium 4.

[ppgrainbow]

Officially, "Windows Protection Error" referencing to either NDIS or IOS occurs when CPU speeds greater than 2.15 GHz (or 2,147,483,647 hertz) is too fast for Windows 95. This issue also affects users of the original release of Windows 98 (v4.10.1998).

Here's the original article on why Microsoft never provided a fix for Windows 95 or Windows 98 operating systems: https://web.archive.org/web/20120315005614/http://support.microsoft.com/kb/312108

You will need to download the patch to overcome this limitation: http://lonecrusader.x10host.com/fix95cpu.html

Users on Windows 98 Second Edition or Windows Millennium Edition don't need the patch.

Edited August 19, 2017 by ppgrainbow

[rloew]

Windows 95 RTM cannot handle CPU speeds higher than 350MHz. The FIX95CPU Patches, linked by ppgrainbow above, will fix this as well.

[LoneCrusader]

2 hours ago, CamTron said:

I had an extra 160 GB hard drive lying around, so I decided to install Windows 95 (original RTM version) on my Dell Dimension 4300 just for kicks. This computer has a 1.5 GHz Pentium 4 (Willamette), and 512 GB of PC133 RAM. I was able to install Windows 95 okay, but when I booted it up, I got the dreaded "Windows protection error. You need to restart your computer." message. However, my BIOS has a way to lower the CPU speed, so I changed that setting from "normal" to "compatible", and it was able to boot Windows 95. The only problem is that it runs very slow like that, and I'd like to be able to use the full speed of the CPU. I've installed Windows 95 in virtual machines on 3.4 GHz processors, so I'm not sure why it has trouble with a 1.5 GHz Pentium 4.

The actual speed limit that causes the error varies between AMD and Intel CPU's. There are two different errors each with different speeds.
The first problem (Windows Protection Error in IOS.VXD) occurs at around 350MHz on AMD and somewhere around 1000MHz on Intel (I used to know the Intel limit more specifically, but it's been a long time.)
The second problem (Windows Protection Error in NDIS.VXD) occurs at 2.1GHz on Intel and I'm not sure of the limit on AMD; rloew may know this.

Both of these are fixed for all versions of Windows 95 by my FIX95CPU v3 patch. More info here if you want.

59 minutes ago, ppgrainbow said:

Officially, "Windows Protection Error" referencing to either NDIS or IOS occurs when CPU speeds greater than 2.15 GHz (or 2,147,483,647 hertz) is too fast for Windows 95. This issue also affects users of the original release of Windows 98 (v4.10.1998).

Here's the original article on why Microsoft never provided a fix for Windows 95 or Windows 98 operating systems: https://web.archive.org/web/20120315005614/http://support.microsoft.com/kb/312108

You will need to download the patch to overcome this limitation: http://lonecrusader.x10host.com/fix95cpu.html

Users on Windows 98 Second Edition or Windows Millennium Edition don't need the patch.

Microsoft did provide a HotFix solution for 98 First Edition. They later revised that KB article with a LIE that no fix was available. The HotFix can be found online. I think I gave MDGx a copy, so it should be there.

Microsoft also provided a solution for 95 OSR2 but they failed to make this known (intentionally, or just oversight?). NDIS.VXD 4.00.1113 from Dial-Up Networking 1.4 for Windows 95 contains updated code that fixes the issue.

All of this is covered at length in the thread I linked above.

[ppgrainbow]

Thank you so much for the information. I suspect that CPUs faster than 2.15 GHz weren't available until at least January 2002 when Intel released newer versions of the Pentium 4 processor to include speeds up to 2.2 GHz which at the time was untested on Windows 95.

Edited August 20, 2017 by ppgrainbow

[CamTron]

Thanks. That patch fixed it. I knew about the 2.1 GHz limit, but I didn't realize that it had problems with 1 GHz Intel chips. It's working fine, but the only piece on hardware I have drivers for is the Nvidia GeForce2 graphics card, so I can't do much else besides gaming without sound.

[LoneCrusader]

10 hours ago, CamTron said:

Thanks. That patch fixed it. I knew about the 2.1 GHz limit, but I didn't realize that it had problems with 1 GHz Intel chips. It's working fine, but the only piece on hardware I have drivers for is the Nvidia GeForce2 graphics card, so I can't do much else besides gaming without sound.

There may be more 95-compatible drivers available than you think. Post all the specs of the system here. Grab the SCANPCI tool rloew attached to ruthan's X99 chipset thread and run it in DOS before Windows loads. Post the output here so I can see what specific Device ID's are in your computer.