One guess is you could have kept all your childhood viruses on there, kudos, not many people go for that level of authenticity. 🤣

BitWrangler wrote on 2026-10-02, 22:00:

One guess is you could have kept all your childhood viruses on there, kudos, not many people go for that level of authenticity. 🤣

Unfortunately, original HDD was wiped or swapped, so this is a modern install of WinXP. My main suspect is that OneCoreApi may have left something even after uninstallation. Probably I'll have to reinstall clean WinXP SP3 again, this time without OCA and LegacyUpdate updates.

Or might it be because of USB mouse (Microsoft wheel mouse optical) or some hidden IRQ conflict? Maybe the GPU is somehow too fast for this? There was an Ati Radeon 9600 128mb agp that I was blaming first, then I added RAM to 768mb, changed CPU from Willamente 1.8 to Northwood 2.0 (twice the cache), but upgrade improved almost nothing.

Caps around CPU VRM are just a little bulging and there are some neutralized (by me) corrosion from cat urine (not capacitor acid), but in theory this shouldn't affect performance untill it breaks afaik.

Combining a Pentium 4 with SDR SDRAM was never a good idea and was only done out of desperation. If it were me, I'd install Windows 2000 or XP SP1 to try and lighten the load the OS adds.

It definitely should be faster for Warcraft 3 with that CPU and that video card. My instinct makes me think there's an AGP speed issue from a misconfigured/absent chipset driver.

Unfortunately, original HDD was wiped or swapped, so this is a modern install of WinXP.
My main suspect is that OneCoreApi may have left something even after uninstallation.
Probably I'll have to reinstall clean WinXP SP3 again, this time without OCA and LegacyUpdate updates.

I've never had such issues with OneCoreAPI, though I also never used it on a Pentium IV.
Speaking of the Pentium IV, I had a Prescott once and it ran Windows XP SP2 very well at the time.
I remember that HyperThreading was enabled in CMOS Setup and that Task-Manager showed two CPUs.
I wonder if the Northwood can do HT, too, maybe it would help performance wise.

crapasanya wrote on 2026-10-02, 21:03:

and what are the chances of fixing it without reinstalling the OS?

In those cases the pretty obvious way is to do a second parallel installation, and dual boot with it

So you can compare them and you haven't to waste tons of your time reinstalling things each time.

If the problem persist on the fresh install it's a HW/BIOS problem

If the problem goes away, you have all the time to try to fix the old install, or keep the new one as the main.

Whatever the result a second install is obviously a life saver in case of serious problems on the first one.

Having a single install is just stupid, no matter if it works correctly or not, no matter if we are talking about DOS, XP or W10/11

I’ve heard that not updating the chipset drivers for NetBurst platforms can cause performance issues, but that was primarily in reference to Willamette and possibly pre-Windows XP (but I could be misremembering). Worth a shot, maybe?

I have some captures from a Northwood 2.4 GHz computer on my YT channel that might help you out, to get a reference for how a Northwood system should roughly perform. At least for games like Mafia, UT2003, Postal 2, Doom 3, Butcher Bay and Morrowind (etc.).

Warcraft 3 was good on a Pentium III 600MHz. Maybe running some benchmarks would help to find out what is holding back your P4. Detailed results from 3dmark01 or 3dmark03 would be illuminating, or perhaps SuperPi or CPU-Z.

bakemono wrote on 2026-10-03, 22:58:

Warcraft 3 was good on a Pentium III 600MHz. Maybe running some benchmarks would help to find out what is holding back your P4. […]

Yeah, benchmarks of the same CPU from back then would be helpful for troubleshooting performance. This old Anandtech article should provide some good referential numbers for Northwood 2.0 (and 2.2) GHz: https://web.archive.org/web/20021115032647/ht … tml?i=1574&p=12
The URL is set to the 3D gaming performance page, but you can browse to a different page via the drop-down index menu in the article, in case you want productivity numbers.

SP3 for XP can hurt performance quite a bit in certain areas.

I would get the WSUS offline package for XP from archive.org, wipe it and do a clean install and only use WSUS offline to do the updates... even with SP3.

You can also disable quite a few unneeded services in XP.

cyclone3d wrote on 2026-10-04, 06:30:

SP3 for XP can hurt performance quite a bit in certain areas.

I would get the WSUS offline package for XP from archive.org, wipe it and do a clean install and only use WSUS offline to do the updates... even with SP3.

You can also disable quite a few unneeded services in XP.

Wiping is a shortcut useful to reach the result (wasting a ton of time), but has 2 important side effects.

1) 99% of the time you loose something of valuable, package that is not available anymore, a custom setting on what you spent days of tests and tweaking, a passwrord stored in the browser, whatever else.

2) you learn nothing.

Most of the skill working on PCs comes from fixing an installation that doesn't work as you expect.

In two words formatting / wiping is for loosers.

If you want to start a clean install you don't need to format anything, just shrink the main partition, and install a parallel installation.

Since Win7 you don't even need that, thanks to the marvel of native vhds.

Once you have a fresh/clean/parallel installation you can start to import copy things from the old one/ including the whole user profile, in minutes not hours or days.

Then you can install the few programs that really needs a proper installation process (say Microsoft office), which are a tiny minority in 2026.

3) Often, like in the case above, You can't even know if the problem you're facing is because the SW, if the problem comes from HW, wiping is 100% wasted time, you have lost your beloved system, you have wasted time reinstalling, and your problem is still there, which is pure masochism.

The Solutor wrote on 2026-10-04, 07:42:

Wiping is a shortcut useful to reach the result (wasting a ton of time), but has 2 important side effects. […]
Show full quote

cyclone3d wrote on 2026-10-04, 06:30:

SP3 for XP can hurt performance quite a bit in certain areas.

I would get the WSUS offline package for XP from archive.org, wipe it and do a clean install and only use WSUS offline to do the updates... even with SP3.

You can also disable quite a few unneeded services in XP.

Wiping is a shortcut useful to reach the result (wasting a ton of time), but has 2 important side effects.

1) 99% of the time you loose something of valuable, package that is not available anymore, a custom setting on what you spent days of tests and tweaking, a passwrord stored in the browser, whatever else.

2) you learn nothing.

Most of the skill working on PCs comes from fixing an installation that doesn't work as you expect.

In two words formatting / wiping is for loosers.

If you want to start a clean install you don't need to format anything, just shrink the main partition, and install a parallel installation.

Since Win7 you don't even need that, thanks to the marvel of native vhds.

Once you have a fresh/clean/parallel installation you can start to import copy things from the old one/ including the whole user profile, in minutes not hours or days.

Then you can install the few programs that really needs a proper installation process (say Microsoft office), which are a tiny minority in 2026.

3) Often, like in the case above, You can't even know if the problem you're facing is because the SW, if the problem comes from HW, wiping is 100% wasted time, you have lost your beloved system, you have wasted time reinstalling, and your problem is still there, which is pure masochism.

Guess you missed the post where this was already a clean install but with what I am pretty sure are some quarionable 3rd party update packages.

I've been doing IT for way too long to bother with trying to fix a messed up clean install. Started doing it related things in 1993.

XP is pretty fast to install and update, compared to chasing weird performance issues for hours and possibly days due to a messed up install.

I like starting from a known good configuration and not with some 3,rd party update packages and poor performance

The Win 98 unofficial SP3 is also trash and causes all sorts of problems. It was fine when it was mainly just packaged official updates, but then other stuff got added to it, including things from newer Windows OSes and it became a horribly unstable mess.

In that case, my advice would be the same... Start fresh.

cyclone3d wrote on 2026-10-04, 08:44:

Guess you missed the post where this was already a clean install but with what I am pretty sure are some quarionable 3rd party update packages.

These days legacyupdate works pretty well no need to resort to amateurish premade packages, assuming that updating makes sense, and often the answer is just NO.

I've been doing IT for way too long to bother with trying to fix a messed up clean install. Started doing it related things in 1993.

My first Computer was from '82, but I started playing with IBM compatibles seriously in 93 as well, before that what we call now just "PC" were pretty boring and useless for a kid.

That said, I don't dare to suggest you to change your habits, you're grown up enough to have learnt everything you had to learn.

My point is that something that MAY be valid for you and me, could be a bad suggestion for a 2026's kid

XP is pretty fast to install and update, compared to chasing weird performance issues for hours and possibly days due to a messed up install.

A parallel installation is meant exactly to prevent that.

The Win 98 unofficial SP3 is also trash and causes all sorts of problems.

9x is usually a different matter, there the first thing to do is an in place upgrade, something that usually works pretty well also in 2000+

In that case, my advice would be the same... Start fresh.

That's the point start fresh != wipe/format.