I don’t build retro rockets because I want the ultimate machine (there’s always a better component out there). I build them because they’re Awesome! This is the kind of performance I wish I had when I installed Windows 98 Beta 3 on a Pentium 133 in early 1998. I do it for myself (although I sometimes post here to show off, a bit). I don't see any issue if another enthusiast wants to replicate my projects or those of someone else.
I use modernish parts to get the best performance out of the components. I prefer to operate components at stock settings (I dabble with overclocking, but I don’t care for it), so I try to find excellent performance out of the box while maintaining maximum compatibility with key functions. Those functions for me include: high-speed data storage access, optical drive access for CD and DVD playback, stereo sound (ideally with advanced audio effects), high-resolution and high color-depth graphics (ideally with advanced 3D effects), a large pool of accessible memory, and high-speed networking.
I also try to balance power and volume requirements (I sometimes build in smaller cases), cost, and component quantity due to limited physical storage space.
Yes, modern, multi-core processors do waste silicon space on the die when using Windows 98 since it cannot handle more than one processor/core. On the flipside, many Intel and AMD processors boost a single core to full Turbo speed automatically (4 GHz on my Ivy Bridge system and 4.4 GHz on my Devil’s Canyon system). A single core operating at full speed also uses only a fraction of the maximum power rating for the CPU, so power delivery and cooling aren’t a serious concern as long as the cooler can handle the chip’s hotspots.
In addition, modern CPUs incorporated the RAM controller into the CPU itself which improves performance. That coupled with newer high-speed RAM boosts performance greatly compared to older architectures such as the Pentium 4 and Core 2 platforms (newer AMD architectures also benefit from this approach). RAM access is completely transparent to the OS, so Windows 98 benefits from faster RAM without any software modification. Some systems may require RLoew’s RAM patch due to non-standard memory maps, though.
Yes, the ATI R400-series doesn’t provide support for certain fog and palletized color effects. I consider this a matter of taste. I used ATI-based cards in the late 90s and early 2000s, so I never had these effects enabled for use in the games I played back then. While I’ve seen these effects more recently (and appreciate them), the fact of the matter is that those games look the way I remember them on my x800. I can live with that. I don’t have any serious issues with older DirectX/OpenGL titles that I own with this card. I can also run DirectX 9 games (such as Call of Duty) very well within Windows 9x and Me.
Yes, Nvidia and ATI/AMD cards don’t natively support the Glide API. I again consider this a matter of taste. Like above, I used DirectX and OpenGL for the games I played back then, and that’s how I remember them. I don’t own any 3DFX cards, so I’m really not a connoisseur of Glide effects.
Finally, I prefer to use Windows 9x for Windows software. DOS compatibility (including the DOS VM within Windows) is not a priority for my builds. I have other computer builds (both period correct and retro rockets) better suited for high-performance DOS. I will say my Win 9x retro rockets are more than fast enough to run DOSBox well for DOS games if I choose to play them.