JayPointSystems wrote on 2025-10-31, 14:05:

I’ve been building retro PCs for quite a while, and my project series was actually already wrapped up. But a year ago, I happene […]
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I’ve been building retro PCs for quite a while, and my project series was actually already wrapped up. But a year ago, I happened to stumble across an Intel Celeron 950 QHB6QS (Qualification Sample, Coppermine‑128) on eBay. That find immediately lit a spark, so I grabbed it right away. Not long after, I came across an ELSA GLoria II 32 (NVIDIA Quadro SDR, GeForce 256 / NV10GL) in the form of an engineering release - and of course, I had to pick that up too.

After a quick test run, though, the hardware went straight into a drawer. I knew I’d eventually do something with it, but the right idea just wasn’t there yet.

Some time later I ran into an online article about a leaked Half‑Life beta. From there I fell down the rabbit hole of unfinished games, which eventually led me to unreleased versions of Windows - another rabbit hole entirely. During those endless late‑night dives I came across the codename “Neptune” and that’s when the idea hit me: why not combine all this unfinished stuff and see if I could actually get it running? The timing lined up perfectly.

By the end of 1999, Intel’s new Coppermine architecture had just arrived, the GeForce 256 was shaking up 3D as the first true GPU, and Microsoft was experimenting with Neptune - all happening at once.

So, against my own expectations, I kicked off another project: I put everything together and installed Windows Neptune 5111 for the first time. Over the following weeks I kept working with the system - reinstalling, making backups, restoring them again. I went through every high and low until, after countless hours of trial and error, I finally got the system running stably, and in a form that, as far as I know, has never been documented before.

Real, hardware‑accelerated Direct3D and OpenGL under Windows Neptune 5111.

Something I could hardly believe myself after all those attempts. I installed and tested around two dozen games from that era - including the Half‑Life beta - and every single one ran consistently stable. Performance was surprisingly good. In 3DMark 99 Max the setup scored around 5,700 points - capped only by a VSync you can’t disable. What I ended up with wasn’t just another period‑correct high‑end build, but a Frankenstein that truly earns the name.

The entire project - from assembly to testing - is documented in the linked video:

https://www.youtube.com/watch?v=DxOB0AT9bPI

This video is also available on archive.org for historical reference and long‑term preservation.

cool build 😀 i first did a neptune build back in 2019, same 5111 version, from what i remember this one has a timebomb so you have to set the date accordingly in the bios, im pretty sure there is a fixed version or a way to bypass it but i forget now, i was using a 478 socket P4 with an intel 865 chipset + FX5200, the instability i think came from using the wrong drivers and there was a lot of trial an error finding the right ones, if i remember right i ended up using a mix of M.e and 2000/xp drivers, and eventually managed to have a stable system.

the system i had it on was running every os from dos to win7, as well as neptune and win96 nashville. ive also got whistler and longhorn i was planning to install but never got round to it.

also with 3dmark99 you need to use the patched version to unlock the framerate, and your score should then double.

Awesome build! I have thought about doing a build that involved any samples or early versions of devices that I have, but the thought never occurred to me to use a preview\beta\unreleased OS as well!

(Also, just curious, did you use some funky filters on those photos or did you use a period correct 1999 digital camera as well?)

DudeFace wrote on 2025-10-31, 15:59:

cool build 😀 i first did a neptune build back in 2019, same 5111 version, from what i remember this one has a timebomb so you have to set the date accordingly in the bios, im pretty sure there is a fixed version or a way to bypass it but i forget now, i was using a 478 socket P4 with an intel 865 chipset + FX5200, the instability i think came from using the wrong drivers and there was a lot of trial an error finding the right ones, if i remember right i ended up using a mix of M.e and 2000/xp drivers, and eventually managed to have a stable system.

the system i had it on was running every os from dos to win7, as well as neptune and win96 nashville. ive also got whistler and longhorn i was planning to install but never got round to it.

also with 3dmark99 you need to use the patched version to unlock the framerate, and your score should then double.

Yes, there are actually two builds floating around — one with a timebomb and one without. I went with the latter. 🙂

From my experience, stability isn’t really the issue out of the box — though of course that’s easy to say now, after sinking countless hours into it. In the end, the trick turned out to be surprisingly simple:

Windows Neptune runs best when you leave it alone! Stick to hardware it already has drivers for (that’s also the key to getting real hardware acceleration), don’t mess with the system components, drivers, or things like DirectX, and don’t start swapping hardware around afterwards. Even something as trivial as plugging in a USB stick once and later removing it can trigger a blue screen — I tested that so you don’t have to. 😀 You can install games and apps to your heart’s content, but otherwise just let Neptune be!

The only extras I’d recommend are the old Windows 2000 Application Compatibility Toolkit, which helps stubborn NT‑era games run, and disabling hibernation plus the Still Image service. Do that, and the whole setup turns out rock solid.

I also tried the whole setup under Windows ME with proper drivers (NVIDIA Detonator 7.76 and VIA chipset 4.35), but with roughly 6,100 points the score ended up only marginally higher. I then gave it another run with a GeForce2 GTS and got around 8,000 points in 3DMark99. So even with that card the numbers don’t really go much higher in my experience.

Ozzuneoj wrote on 2025-10-31, 16:26:

(Also, just curious, did you use some funky filters on those photos or did you use a period correct 1999 digital camera as well?)

Honestly, I have no idea why the photos look like that. Maybe HEIC images just get processed differently on the forum?! Otherwise I’d say it must be a secret VOGONS filter to make everything look period‑correct. 😀

JayPointSystems wrote on 2025-10-31, 16:52:

Ozzuneoj wrote on 2025-10-31, 16:26:

(Also, just curious, did you use some funky filters on those photos or did you use a period correct 1999 digital camera as well?)

Honestly, I have no idea why the photos look like that. Maybe HEIC images just get processed differently on the forum?! Otherwise I’d say it must be a secret VOGONS filter to make everything look period‑correct. 😀

Hmm... I'm thinking it must be HEIC since pictures don't normally look like that on here. To be honest, I've never used that format myself (though I understand it is superior). If you convert them to .jpg the forum should have no problem with them. 😀