hi, I have a system with socket 478 3.4ghz Northwood so am I better off with a socket 775 system for speedstep feature to make this truly useful?

zapbuzz wrote on 2026-08-19, 17:31:

hi, I have a system with socket 478 3.4ghz Northwood so am I better off with a socket 775 system for speedstep feature to make this truly useful?

It would help, but not significantly; for the Pentium 4 / Pentium D CPU lines, multipliers range roughly from 12× to 23× depending on the model, and the dynamic reduction via EIST is typically in the 25–40% range.

For Core 2 Duo / Core 2 Quad, the minimum multiplier is typically 6× against a maximum of roughly 10× to 13× (depending on the model), allowing for a reduction of about 40–55%.

The downside is that these CPU families are so fast that a 50% reduction alone won't be enough to make speed-sensitive games—especially DOS titles—run correctly.

In my opinion, the ideal CPU is a Northwood-core Pentium 4 running between 2 GHz and 2.8 GHz; using *p4tool*, you can achieve speeds comparable to 286, 386, 486, Pentium, or Pentium II systems by combining various throttling options—specifically CD, DS, and DSBTS, along with settings O1 through O8 for fine-tuning.

OttoPS wrote on 2026-08-22, 11:55:

It would help, but not significantly; for the Pentium 4 / Pentium D CPU lines, multipliers range roughly from 12× to 23× dependi […]
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zapbuzz wrote on 2026-08-19, 17:31:

hi, I have a system with socket 478 3.4ghz Northwood so am I better off with a socket 775 system for speedstep feature to make this truly useful?

It would help, but not significantly; for the Pentium 4 / Pentium D CPU lines, multipliers range roughly from 12× to 23× depending on the model, and the dynamic reduction via EIST is typically in the 25–40% range.

For Core 2 Duo / Core 2 Quad, the minimum multiplier is typically 6× against a maximum of roughly 10× to 13× (depending on the model), allowing for a reduction of about 40–55%.

The downside is that these CPU families are so fast that a 50% reduction alone won't be enough to make speed-sensitive games—especially DOS titles—run correctly.

In my opinion, the ideal CPU is a Northwood-core Pentium 4 running between 2 GHz and 2.8 GHz; using *p4tool*, you can achieve speeds comparable to 286, 386, 486, Pentium, or Pentium II systems by combining various throttling options—specifically CD, DS, and DSBTS, along with settings O1 through O8 for fine-tuning.

Thanks I thought my CPU would be a bit fast I do however have slower ones too.

zapbuzz wrote on 2026-08-19, 17:31:

hi, I have a system with socket 478 3.4ghz Northwood so am I better off with a socket 775 system for speedstep feature to make this truly useful?

I've done a bunch of testing with both Northwood and Cedar Mill processors (the latter with Speedstep).

While the Speedstep feature is handy for fine-tuning speeds in conjunction with other throttling methods, it's not required. With a combination of cache disabling and other methods, it's possible to hit varying levels of performance approximating 386, 486 and Pentium class systems.

It also depends on the specific speed-sensitive games you are running and how they behave with different types of throttling.

Hello! I really liked the p4tool; it allowed me to reduce my Pentium 4's performance to a level sufficient for comfortable playing Jazz Jackrabbit (which was unachievable with ODCM). One problem: I can't get p4tool to run with EMM386. It hangs with this memory manager in any mode - RAM or NOEMS. And I need it to launch SBEINIT (DOS Audigy driver). Please tell me if there are memory managers that work correctly with p4tool (it doesn't freeze on startup). I would be very grateful for working lines with parameters from your files autoexec.bat and config.sys.

Yuriy_X wrote on 2026-08-22, 14:41:

Hello! I really liked the p4tool; it allowed me to reduce my Pentium 4's performance to a level sufficient for comfortable playing Jazz Jackrabbit (which was unachievable with ODCM). One problem: I can't get p4tool to run with EMM386. It hangs with this memory manager in any mode - RAM or NOEMS. And I need it to launch SBEINIT (DOS Audigy driver). Please tell me if there are memory managers that work correctly with p4tool (it doesn't freeze on startup). I would be very grateful for working lines with parameters from your files autoexec.bat and config.sys.

Hi!

To use p4tool with protected-mode memory managers, the manager must pass through certain CPU privileged instructions; unfortunately, EMM386 does not do this.
Fortunately, however, JEMM386 does support this. It is a fantastic upgrade over EMM386 for DOS—faster and the most compatible of all the alternative memory managers.

Give it a try; it will undoubtedly yield great results.

Unfortunately, I'm having another problem with the Jemm386: SBEINIT.COM saying error "Could not allocate code/patch RAM. Creative SB16 Emulation Driver NOT loading". I can't figure out why it initializes fine with the EMM386, but won't with the Jemm386.

Creative's Sound Blaster compatibility driver for DOS depends on EMM386 specifically, it uses undocumented functions to capture and redirect writes to the DMA controller. It won't work with JEMM. You can try SBEMUL or VSBHDA instead, both can work with the Live but use their own memory managers.

But Adlib emulation in software requires more CPU power so you won't be able to slow it down to 386 levels without causing the sound to skip or break entirely. That's the Catch-22 of DOS gaming with PCI sound.

onethirdxcubed wrote on 2026-08-22, 20:21:

Creative's Sound Blaster compatibility driver for DOS depends on EMM386 specifically, it uses undocumented functions to capture and redirect writes to the DMA controller. It won't work with JEMM...

For me the Creative drivers work with JEMM386. If I remember correctly there are even command line arguments for this purpose.

Yuriy_X wrote on 2026-08-22, 18:21:

Unfortunately, I'm having another problem with the Jemm386: SBEINIT.COM saying error "Could not allocate code/patch RAM. Creative SB16 Emulation Driver NOT loading". I can't figure out why it initializes fine with the EMM386, but won't with the Jemm386.

jemm386 has a specific command-line option for sbinit/sbeinit compatibility: `sb`.

You can find it here: https://github.com/FDOS/emm386
In the "Commandline options" section.

I'm interested to know if it works for your case.

OttoPS wrote on 2026-08-22, 20:48:

jemm386 has a specific command-line option for sbinit/sbeinit compatibility: `sb`.

Unfortunately, the SB parameter had no effect.

Yuriy_X wrote on 2026-08-22, 21:36:

OttoPS wrote on 2026-08-22, 20:48:

jemm386 has a specific command-line option for sbinit/sbeinit compatibility: `sb`.

Unfortunately, the SB parameter had no effect.

It's a very strange problem. Have you tried `sbemu`? You might be able to use your PCI sound card that way.

OttoPS wrote on 2026-08-22, 21:57:

It's a very strange problem. Have you tried `sbemu`? You might be able to use your PCI sound card that way.

Thanks for the recommendations. I'll try to find ways to use the Yamaha 724 (which I also have) under DOS. I know this will require a different motherboard (not Intel) with DDMA support, which can be used by PCI sound cards.

OttoPS wrote on 2026-08-22, 21:57:

Have you tried `sbemu`? You might be able to use your PCI sound card that way.

I tried it, but I really didn't like the results. Bugs, sound lag, and it doesn't play MIDI (SF2).

Yuriy_X wrote on 2026-08-23, 09:22:

OttoPS wrote on 2026-08-22, 21:57:

Have you tried `sbemu`? You might be able to use your PCI sound card that way.

I tried it, but I really didn't like the results. Bugs, sound lag, and it doesn't play MIDI (SF2).

Then try VSBHDA. It can also play MIDI (SF2).

I still managed to get P4TOOL and SBEINIT to work together. I just added QEMM after HIMEM.SYS instead of EMM386 in the following way: DEVICE=C:\QEMM\QEMM.SYS. As a result, SBEINIT starts successfully, and P4TOOL executes all commands without freezing. I’ve already tested several games in DS mode, namely: WarCraft II, Blackthorne, and Jazz Jackrabbit. The first one works without errors and has smooth scrolling; in the second one, music plays during the intro (as it should on a Pentium‑level system); the third one starts without Runtime Error 200 and works without the speed jumps typical of ODCM and throttling. I hope this information will be useful for those who also have problems with P4TOOL with EMM386 and JEMM386. Thanks to the author of this program for a great tool!

I’m working on new features for p4tool and would like to know if I can count on you for beta testing and to suggest new ideas for implementation.

For now, the new features I’m considering are:

* EMM386 compatibility via VCPI.

* Windows 9x/ME compatibility by modifying the IDT and accessing Ring 0.

* Consolidation of new slowdown modes based on BTS (e.g., using MMIO buffers, unaligned pointers, and others you might suggest).

* Extending p4tool to other CPU families; I believe support up to Intel Panther Lake is possible.

* Forking the VSBHDA project: I’ve found that some of its incompatibilities stem from the CPU's effective speed—since emulation consumes CPU resources, it conflicts with throttling systems. My idea is to create a fork that temporarily disables throttling whenever VSBHDA needs to process sound buffers, access hardware, etc., and restores it afterward.

Many of these approaches are unorthodox but effective—please spare me the "engineering monocle" complaints. 😉

I'd be happy to help out with more testing. I've been impressed with being able to hit 386 DX-33 levels of performance without needing ODCM throttling thanks to P4Tool.

I've got my P4 test bench set up again, and I'm also interested in the possibility of EMM386 compatibility.

And been meaning to try QEMM as well.

I'd also be happy to help you out with testing - my system is an Ipox 4GVI83 motherboard with 1x1024 MB DDR-333 CL2.5, A P4 Northwood with 533 FSB and HT disabled in the BIOS, as well as 3 sound cards: an Opti/AD1845/OPL3 based card, a Guillemot Maxi Sound 64 Dynamic 3D (ESS Audiodrive 1868F + Dream SAM 9407) plus a Creative CT1920 Goldfinch (only the EMU8000 portion of the AWE series, bug free, with expansion memory, needs no IRQ or DMA).
The ISA slots have fully working DMA mechanics because of the great PCI IDE bridge chip on this amazing industrial board.
I happened to get it for free because someone threw it away, believing it was defective when no AGP graphics card would work in its ADD slot... anyway it works just fine with PCI or ISA graphics cards, so I'm using a Geforce FX 5200 128 MB 64bit PCI since sadly my Axle Geforce FX 5500 256 MB 128bit died. With a 128 bit memory bandwidth, these entry level Geforce FX cards are just perfect for W9x gaming at enhanced resolutions with AA or even Glide games via a wrapper.

OttoPS wrote on 2026-09-02, 22:38:

* Extending p4tool to other CPU families; I believe support up to Intel Panther Lake is possible.

Panther lake is the just released Core Series 3, so the implication is that it basically works on all Intel mainline consumer processors from Willamette to now?