My thought is the following: if you want to make a build to install Windows 95 on which maintains ISA legacy compatibility, you will have to turn to platforms with Pentium 3 or Athlon (even XP) CPUs. If legacy ISA compatibility doesn't interest you, I believe you can go as far as late Pentium 4 and Athlon XP systems; besides I think not because the motherboard chipsets no longer had compatible drivers (therefore excluding the mod drivers). I hope I was helpful to you 😉

sliderider wrote on 2023-03-31, 11:02:

So, what's the most powerful system that you can build, basically, that will still run Windows 95?

For now it would be something in the realm of an Athlon T-Bird 1.4 GHz and Radeon 9800 Pro - something akin to this.

I did experiment with a ViA KT400 / AthlonXP-based platform and Windows 95 does run, but you're starting to run into the situation where features such as USB 2.0, sound cards, faster video cards etc. just won't have drivers. Edit: If you're willing to overlook not being able to utilize some advanced features on your system such as SATA (controller must be set to IDE-mode), USB 2.0, Gigabit-ethernet etc., then you can go 2 GHz+ AthlonXP and Radeon 9800 Pro, even - no problem by itself.

It's a tough question to answer because of a couple of major changes to PC interfaces over the years. You end up either prioritizing CPU performance or GPU performance. You have to pick one or the other to find a sweet spot.

For GPUs, the fastest/newest cards with Windows 95 Retail support were the Radeon 9000 series. I've had good luck getting a Radeon 9000 PCI and Radeon Mobility 9000 (AGP) working with Omega drivers on Win95 Retail. The fastest/newest for Windows 95 OSR2 are either the Radeon 9000 series or the GeForce FX series. The fastest cards for Windows 95 only use the AGP interface, though.

For CPUs, you can push Windows 95 pretty far. Personally, I run Windows 95 (both Retail and OSR2) on a Core i5-3570 (3.8 GHz Turbo) for my retro rocket. I'm thinking about testing Win95 on my Core i7-4790k (4.4 GHz Turbo), but I haven't gotten around to it. Still, many modern CPUs can still run Windows 95. But, here's the rub: these platforms offer PCI slots, not AGP slots.

If you want the fastest GPU with Win 95, then you need to use a CPU/motherboard with AGP slots unless you have a rare AGP-to-PCI adapter. That would limit you to a Core 2 Duo or Quad running around 3 GHz (not the fastest CPU possible). If you want the fastest CPU, you need to use a mainboard with PCI slots and a slower, budget PCI GPU. You have to compromise, unfortunately.

Personally, I go for the fastest CPU. A Radeon 9000 PCI offers performance close to a Radeon 7500, and it supports the DirectX 8.0 API. The GeForce FX 5200 PCI offers similar performance and likewise provides DirectX 8.0 support. The FX 5200 also supports table fog and palletized textures.

The bigger issue Windows 95 2.1GHZ flaw on intel and AMD's 350mhz error, both have fixes, one offical for the AMD, but the 2.1 fix came out alot later. Honestly I'd stick to something like Pentium II or AMD K6

candle_86 wrote on 2023-04-01, 03:05:

The bigger issue Windows 95 2.1GHZ flaw on intel and AMD's 350mhz error, both have fixes, one offical for the AMD, but the 2.1 fix came out alot later. Honestly I'd stick to something like Pentium II or AMD K6

It's a pretty easy fix, though. I run the "fix" floppy image from a bootable CD right after the first phase of the Windows 95 install. While I'm at it, I also edit the SYSTEM.INI to artificially limit the RAM to 768 MB to avoid the memory error as well. Win95 works like a charm after that.

I will say that I also have to manually install the PCI Bus from the New Hardware wizard on more modern platforms. The installer doesn't detect the PCI Bus automatically for some reason. Once I install the PCI Bus driver, Windows 95 does detect all of the connected devices.

Personally, I wouldn't expect the experience to improve enough relative to difficulty to achieve over 1.5Ghz or so to be worth the bother. Though trying to have newest rig that can do later OS stuff, and have win 95 would be desirable I guess. I think though the main problem is gonna come with using it for any gaming, if there's any speed tweaky windows games, it's the first crop of ddraw, up to dx5 stuff that can run on Win95. I would expect problems by 300Mhz with some of them, and most of them at 500Mhz plus.

BitWrangler wrote on 2023-04-01, 03:51:

Personally, I wouldn't expect the experience to improve enough relative to difficulty to achieve over 1.5Ghz or so to be worth the bother. Though trying to have newest rig that can do later OS stuff, and have win 95 would be desirable I guess. I think though the main problem is gonna come with using it for any gaming, if there's any speed tweaky windows games, it's the first crop of ddraw, up to dx5 stuff that can run on Win95. I would expect problems by 300Mhz with some of them, and most of them at 500Mhz plus.

This is generally true of all of the retro rockets. I doubt there's serious a use case for running Windows 3.0 at 3.0GHz or OS/2 Warp at 3.8GHz. The same goes for GPUs. A DirectX 9 class card can handle DirectX 5 games pretty well, but at some point you probably won't notice the difference between 300 FPS and 500 FPS in game.

On the other hand, the point of retro rockets is to try to push performance well beyond what the software designers intended. No one would have thought to run Windows 95 on a multi-core CPU running at 3GHz or more in August of 1995 or even August of 1999. Yet it works, and it works surprisingly well.

I personally haven't run into any "unanticipated" speed glitches that I couldn't fix during testing high-performance retro systems over the last 15 years. That actually says a lot about how robust some good programmers made their products from the 90's.

Regardless, the question that started this off had everything to do with maximum performance, not perceptible performance. I say the sky's the limit if that's the intent.

sliderider wrote on 2023-03-31, 11:02:

So, what's the most powerful system that you can build, basically, that will still run Windows 95?

So given the initial responses, I thought I'd ask the OP to clarify if is this a theoretical question or a practical one?

I would suggest a late PIII or Athlon-setup like the one I advertised is still realistically the fastest that makes sense, as most of the software or games that run on Windows 98 will also run on Windows 95 on this hardware (there are starting to be some exceptions, though) - meaning that it can actually be useful insofar as a retro-system ever really can be.

With faster-than-2 GHz CPUs you will quickly run into the issue that no software that runs on Windows 95 can realistically truly benefit from or use its full potential... and even if a Radeon 9800 Pro was an entrant into the DX9-age, no games will run on Windows 95 that require anything later than DirectX 8.0.

Part 1 / 3
I thought I’d experiment a bit by testing two Windows 95 retro rockets: 1) biased toward a fast GPU and 2) biased toward a fast CPU. Here are the results:

Overpowered GPU Configuration:
- Processor: Core 2 Extreme X6800 (2.93 GHz, 2 Core, 2 Thread)
- Motherboard: Asus P5PE-VM (Intel 865PE Chipset; SATA Ports in IDE Compatible Mode)
- RAM: 2GB DDR-400
- Graphics: Medion Radeon 9600 TX (AGP, 297 MHz GPU, 270 MHz DDR)
- Audio: Sound Blaster Live! 5.1
- Networking: Netgear FA310TX
- HD: Generic 128GB SATA SSD (2x 57GB Partitions)

- OS: Windows 95 OSR 2.5 (4.00.950 C) with Plus! 95 and DirectX 8.0
- Chipset Driver: Microsoft Windows PCI Drivers and IDE DMA Driver
- GPU Driver: ATI Catalyst Driver 3.0 and ATI Control Panel 3.0
- Memory: Rloew’s 4GB Memory Patch (PATCHMEM); Memory artificially limited to 1.7GB in SYSTEM.INI for stability (1.0GB for Sandra Tests)

Benchmark Results:
Final Reality (Default)
- 2D Image Processing: 68.06 Reality Marks
- 3D Performance: 14.22 Reality Marks
- Bus Transfer Rate: 5.17 Reality Marks
- Overall Score: 29.01 Reality Marks

3DMark 99 (Default)
- 19,786 3Dmarks
- 47,810 CPU 3DMarks

3DMark 00 (Default)
- 17,035 3DMarks

MDK 2 (1080p, 32-Bit Color, Trilinear Filtering)
- 101.297 Average FPS

RTCW (1280x1024 Max Details)
- 130.83 Average FPS

Sandra 98
- CPU: 7,893 MIPS
- FPU: 2,336 MFLOPS
- Memory: 1,616 MB/s
- Drive Index (C:): 64,893

Sandra 99 (CPU)
- CPU: 8,973 MIPS
- FPU: 4,479 MFLOPS
- Multi-media Integer MMX: 7,175 it/s
- Multi-media Floating-Point: 4,963 it/s
- CPU/Memory: 1,692 MB/s
- FPU/Memory: 1,585 MB/s
- Drive Index (C:): 90,592

Part 2 / 3
Note 1: I don’t have a PCI Readon 8500 or PCI Radeon 9000 (128-bit) for a proper comparison of fast PCI cards compatible with both Windows 95 Retail and Windows 95 OSR2. I used a PCI GeForce FX 5200 as a stand-in even though it is not compatible with Windows 95 Retail nor fully compatible with OSR 2. Its performance is roughly in line with the PCI Radeon 9x00 cards.
Note 2: I couldn’t get Windows to boot on this platform with my Sound Blaster Live! 5.1 for a true apples-to-apples comparison. I used an Ensoniq AudioPCI instead even though the benchmarks didn’t require a sound card.

Overpowered CPU Configuration
- Processor: Core i5-3570 (3.4 GHz Base, 3.8 GHz Turbo, 4 Core, 4 Thread)
- Motherboard: Asus P8B75-V (Intel B75 Chipset; SATA Ports in AHCI Mode)
- RAM: 8GB DDR3-1600 (XMP Enabled)
- Graphics: GeForce FX 5200 (PCI, 250 MHz GPU, 200 MHz DDR)
- Audio: Ensoniq AudioPCI (ES1370)
- Networking: Netgear FA310TX
- HD: Generic 128GB SATA SSD (2x 57GB Partitions)

- OS: Windows 95 OSR 2.5 (4.00.950 C) with Plus! 95 and DirectX 8.0
- Chipset Driver: Microsoft Windows PCI Drivers and Rloew’s AHCI Driver
- GPU Driver: Nvidia Driver 53.04
- Memory: Rloew’s 4GB Memory Patch (PATCHMEM); Memory artificially limited to 1.7GB in SYSTEM.INI for stability (1.0GB for Sandra Tests)

Benchmark Results”
Final Reality
- 2D Image Processing: 103.10
- 3D Performance: 15.39
- Bus Transfer Rate: 4.85
- Overall Score: 40.12

3DMark 99 (Default)
- 8,561 3Dmarks
- 65,774 CPU 3DMarks

3DMark 00 (Default)
- 7,085 3DMarks

MDK 2 (1080p, 32-Bit Color, Trilinear Filtering)
- 57.858 Average FPS

RTCW (1280x1024 Max Details)
- 38.3 Average FPS

Sandra 98
- CPU: 15,107 MIPS
- FPU: 3,182 MFLOPS
- Memory: 12,282 MB/s
- Drive Index (C:): 146,920

Sandra 99 (CPU)
- CPU: 15,626 MIPS
- FPU: 5,159 MFLOPS
- Multi-media Integer MMX: 7,554 it/s
- Multi-media Floating-Point: 5,914 it/s
- CPU/Memory: 13,985 MB/s
- FPU/Memory: 14,537 MB/s
- Drive Index (C:): 156,509

Part 3 / 3
Findings:
1) The Radeon AGP card massively outperformed the GeForce PCI card by about 100% in all 3D benchmarks except Final Reality. I think the faster CPU aided the GeForce card in that benchmark.

2) The Core i5 outscored the Core 2 Extreme by as little as 5.3% and as much as 91.4% in the synthetic integer and floating-point CPU benchmarks. The Core i5 also had memory throughput nearly 8 times greater than the Core 2 Extreme which likely aided its huge wins in raw integer and floating-point performance.

3) The SSD performed nearly twice as fast on a SATA3 port in AHCI mode as it did on SATA1 port in IDE compatibility mode. This is roughly in line with the performance jump from SATA1 to SATA2, and it wouldn’t surprise me if the cheap SSD I used (it costs about $11 US on amazon) is a SATA2 drive.

4) Both systems feel very responsive overall. It’s hard to tell the difference between the two systems while navigating around Windows and running programs. Programs did seem to install a little faster on the Core i5 platform, though.

5) On the other hand, the AGP Radeon ran much better at demanding resolutions and newer games. I generally had no problem pushing Return to Castle Wolfenstein and Jedi Knight 2 to a constant framerate cap with the AGP card. The FX 5200 could play most games around the 60 FPS mark, and would definitely run at 60 FPS with lower resolutions and quality settings in many games. I’d call that playable.

Conclusion:
I don’t think you can go wrong with either build. If you care about game framerates in Windows 95, you’ll definitely want an AGP graphics card. ATI just didn’t bother making PCI versions of their high-end DX8-compatible cards after the Radeon 8500, and Nvidia seems to have skipped PCI cards entirely for the DX8 generation.

If you have a favorite PCI graphics card (or a PCI 3D accelerator), then you can definitely push CPU performance past systems with the AGP bus by using platforms nearly 10-years newer.

I do have to say that I had a good amount of fun with the AGP build. I used a Radeon 7500 as my daily driver for about 4 years back in the day. I would have loved to run a mid-range Radeon 9000-series card back then, but I waited several generations to upgrade. Now I know what I missed-out on.