I’m a bit torn over the P4 platform. I don’t think it deserves the hate, but I also don’t think it’s that great. I almost completely avoided the P4 generation back in the day. I got impatient waiting for the Core 2 Duo, so I bought a cheap Cedar Mill Celeron to pair with a 945P motherboard to later host a Conroe CPU. I ended up replacing both about a year later with a Wolfdale CPU and P45 motherboard. It didn't wow me at the time, but it did seem adequate for then-modern computing.
The P4 was clearly designed to operate at huge clock frequencies (5GHz +) due to the extremely long pipelines in the Netburst architecture. Unfortunately, its design arrived way ahead of its time. Intel’s manufacturing processes over that 6-year period just couldn’t handle that level of performance. The P4 ran too hot and at very high (for the time) power levels, and the branch misprediction rate at low speeds hurt overall performance.
These days, I find both issues quite quaint. Unless you plan to build a SFF system today, nobody seems to bat an eye at CPUs that dissipates 100W+ of power in Turbo mode (some over 200W) and tolerate nearly 100 degrees C during nominal operation now. Intel has also slowly extended the pipelines of modern performance cores to the same length as the Northwood cores, but they improved their branch prediction algorithms dramatically over time. Now that performance cores can operate at 5GHz+, nobody seems to care about either issue.
I actually think that P4s are decent processors in retrospect. My issue is that, outside of a few edge cases that I’ll cover below, they don’t represent the best of breed.
If you want a retro rocket for Win9x, you have plenty of choices that exceed the P4 in raw performance with both AGP and PCIE graphics support. If you want PCI graphics (say a Voodoo card), you also have plenty of better options than the P4. The same goes for Windows 2000, XP, Vista, 7, 10, and 11.
As for DOS, speed kills. Yes, you can slow a modern CPU (such as the P4) down, but you might feel better served with an older platform (386, 486, Pentium, etc.) than a P4. I can’t think of any DOS applications that truly benefit from the raw performance of a P4 that you couldn’t meet with a Pentium MMX 233MHz. I still have issues getting a P4 slow enough for some games even with CPUSPD. And if I want a superfast DOS machine, my Haswell i7 and Yamaha YMF744 can handle both quite well (amongst other fully DOS-compatible systems in my collection).
I do own a P4 system that I use as a retro rocket. In my case, I have a Pentium D 945 (2 core, 2 thread, 3.4GHz) on a DFI/Itox G7S620 to provide nearly the fastest platform possible with functional ISA slots for operating systems that require ISA peripherals to provide sound (Windows 3.0 MME, OS/2 2.x, NT 3.1, and early versions of x86 Solaris). I doubt many people would drop several hundred US Dollars for such a build, but I would. At the same time, I have other builds for different OS’s, and I would not have used a P4 for any of them.
All that said, the later socket 775 P4s on a motherboard with ISA slots do represent a kind of one size fits all system that can effectively handle every x86 and x64 OS from DOS 1.0 to Windows 10 x64 (and likely Windows 11 with mods). I just don't think the P4 platform would be the best for most of them.
