bloodem wrote on 2024-05-11, 16:09:

Shponglefan wrote on 2024-05-11, 16:06:

With just L1 & L2 cache disabled it performs like a mid-range 486. With either ACPI or ODCM throttling, it can hit 386 speeds and lower.

ACPI throttling is quite problematic on most chipsets except for VIA. It apparently works, but when you test enough games you will find that it can cause stuttering and other weird behavior.
Either way, this is very interesting and I'll definitely have to test it out myself. Thanks 😀

Do you have any examples of games that cause stuttering or other issues with ACPI or ODCM throttling?

The only case I've run into so far is Ultima VII. If ACPI or ODCM is applied, the music will slow during the screen shake / earthquake effect. However, the game still playable just with L1 & L2 cache disabling and lower multiplier setting, so ACPI / ODCM throttling is a bit moot in that instance.

Other games I've tested like Descent and Dark Forces don't appear to have issues with ODCM or ACPI throttling. Neither does Police Quest II based on what I've tested so far.

There are also a lot of possible throttling combinations. On my setup between three cache options (both on, both off, or L1 off), six multiplier settings (12x to 17x), ODCM (1 to 8 ) and ACPI (1 to 8 ), there are over 1000 possible combinations.

Since ODCM and ACPI seem to throttle at slightly different rates, I'm curious if there might be certain combinations of those in conjunction with multiplier settings that might be run reliably. But with over 1000 combinations to test, that's a lot of testing. 😅

Shponglefan wrote on 2024-05-11, 16:36:

Do you have any examples of games that cause stuttering or other issues with ACPI or ODCM throttling?

About an year ago I did some testing about that, some of what I remember finding:

Weird waviness in speed, going from fast to slow to fast again:
- Syndicate (game not CPU speed sensitive so doesn't need ACPI throttling)
- The Incredible Machine
- Tyrian (game not CPU speed sensitive so doesn't need ACPI throttling)

Random stuttering:
- Doom (if throttled beyond certain point but not so much it otherwise affects game speed, also not CPU speed sensitive so doesn't need ACPI throttling)
- Mortal Kombat (IIRC only happened between fights when the next opponent was shown)

I feel like there were more. The games that had that odd waviness could be seen from a mile away, but the ones with random stutters weren't as easy. I remember listing games as being ok with ACPI throttling only to notice later they actually were not ok.

theelf wrote on 2024-05-04, 18:57:

A P4 is retro? exept very rare boards no P4+ boards have ISA, then not good for DOS

But okay, you no longer need ISA, PCI OK, SBEMU/VSBHDA.

Shponglefan wrote on 2024-05-04, 18:39:

The Pentium 4 seems to have a mixed rep. I've seen some folks straight-up swear off ever even looking at a Pentium 4, let alone […]
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The Pentium 4 seems to have a mixed rep. I've seen some folks straight-up swear off ever even looking at a Pentium 4, let alone creating a build based on one.

Though most of the negative rep stems from the under-performing Willamette processors and the power hungry Prescott lineup, but I feel like it's tarred the entire P4 lineup.

While there are some P4 builds I've dug through, I'm surprised we don't see more of them and wonder if the negative P4 rep has maybe steered people away from viable and versatile retro-gaming builds.

My own experience building a system around a Cedar Mill processor has been quite positive. I'm still waiting for the other shoe to drop, while continuously being impressed this processor and platform.

What is everyone's thoughts on the P4? Is it underrated? Is there potential for some amazing retro gaming builds that haven't been realized yet?

Good p4, percussion retro. Prescott is well chilled excellent, but it was a long time that he was running with a weak refrigerator/power/poor ventilation house. Excellent retro, I pressed the v2sli world records loosely.

Shagittarius wrote on 2024-05-05, 17:26:

Personally I think anything older than 64bit as far as CPUs go is retro.

+1

agent_x007 wrote on 2024-05-06, 17:17:

leileilol wrote on 2024-05-06, 02:13:

The Pentium 4 launched before 9/11 so I have a hard time being convinced it's not retro.

To be very clear about this : P4 is very much a retro CPU/platform in my point of view.

Completely retro, sure.

kolderman wrote on 2024-05-06, 22:45:

Shponglefan wrote on 2024-05-06, 12:39:

kolderman wrote on 2024-05-06, 02:43:

Forget ISA, this is not a DOS gaming machine.

But... what do I do with my ISA slots then? ¯\_(ツ)_/¯

P4 mobos with ISA a rarer than hens teeth, but practically they are not much use, although I suppose if you only play late DOS games that are not speed sensitive it might be a nice platform to get SPDIF out of say an Audigy2 and mix it with midi sound from a ISA card. Personally I just rely on my C3 and k63 for all DOS gaming needs.

But, even a Ryzen is a full -fledged DOS machine, compatibility is enormous on the X86/64 lines.

Shponglefan wrote on 2024-05-10, 22:26:

On a related note, I never intended for this thread to be a debate about whether the Pentium 4 is consider retro.

Rather, it was a question whether the Pentium 4 is underrated when used for retro computing. IOW, using it for software and games from the 80s and 90s.

Whether or not a platform is considered retro is different from what one uses it for.

Not undervalued, certain variations can only be achieved with this, and remains an evergreen retro.

Shponglefan wrote on 2024-05-11, 13:41:

There are chipsets used with socket 478 and LGA775 boards that also run Windows 98. I believe the fastest supported chipset / processor for Windows 98 would be the i865 / X6800 combination?

Win98SE runs flawlessly on P35, as well as on X58 (LGA1366).

The Serpent Rider wrote on 2024-05-11, 05:35:

Well, you're quite limited in GPU options without AGP.

No, 7900gs, GT, GTX also extends the Win98 area of operation on the PCIe slot.

The Serpent Rider wrote on 2024-05-11, 05:35:

Well, you're quite limited in GPU options without AGP.

You're right, but on the other hand PCI-E R300 and R400 Radeons combined with Win98SE and Catalyst 6.2 drivers are trouble-free.
Radeons X550 are dirt cheap and have enough power to run all Win9x games released up to 2001.

mln wrote on 2024-05-11, 20:58:

Shponglefan wrote on 2024-05-11, 13:41:

There are chipsets used with socket 478 and LGA775 boards that also run Windows 98. I believe the fastest supported chipset / processor for Windows 98 would be the i865 / X6800 combination?

Win98SE runs flawlessly on P35, as well as on X58 (LGA1366).

Those old machines for 98, runs great on the latest configurations 😀, I have a flawless at Ryzen, I wrote in many places and tossed pictures ...

Shponglefan wrote on 2024-05-11, 13:41:

pengan wrote on 2024-05-11, 12:58:

All DDR1 platforms seem a bit awkward to me, including the Pentium 4, Athlon XP and even the Pentium M.
- They don't have good Legacy DOS support like the Socket 370 platforms do

What do you mean by legacy DOS support?

If you are referring to ISA slots, there are socket 478 and LGA775 boards with ISA slots that can be used with ISA sound cards in DOS.

I actually don't think that ISA Pentium 4 motherboards are as rare as some other people in this thread, I'm on your side on this one. It's easy to find motherboards like MS-6555, MS-6571 under US $70 on Aliexpress. But the Socket 370 motherboard with ISA is still easier to find if you consider the local surplus and second hand markets.

My bad impression about Pentium 4 motherboards is mainly on AC97 sound cards
Except Intel 810/815, Socket 370 motherboards with VIA 686A/B, VT8231 or SIS 630 all offer somewhat decent DOS AC97 drivers.
The VT8235/8237 did not have Win95 VxD driver for a long time, and the WDM driver only works with Win98, but the VT8231 works fine with Win95. This problem was not alleviated until 2020 when Carlos S. M.'s modified driver came out: https://retrosystemsrevival.blogspot.com/2020 … 95-drivers.html

DarthSun wrote on 2024-05-11, 20:35:

theelf wrote on 2024-05-04, 18:57:

A P4 is retro? exept very rare boards no P4+ boards have ISA, then not good for DOS

But okay, you no longer need ISA, PCI OK, SBEMU/VSBHDA.

ISA is a must for DOS compatibility, even best PCI cards have much lower compatibility. Did not tested SB Link in my life yet

theelf wrote on 2024-05-11, 22:03:

DarthSun wrote on 2024-05-11, 20:35:

theelf wrote on 2024-05-04, 18:57:

A P4 is retro? exept very rare boards no P4+ boards have ISA, then not good for DOS

But okay, you no longer need ISA, PCI OK, SBEMU/VSBHDA.

ISA is a must for DOS compatibility

Modern drivers have already overwrote this. ETC, Sound - Sbemu/vsbhda.

DarthSun wrote on 2024-05-11, 22:07:

Modern drivers have already overwrote this. ETC, Sound - Sbemu/vsbhda.

No way, not even close. Sbemu/vsbhda are nice projects but compatibility very low and still full of problems

My experience with non-ISA sound devices in DOS is hit and miss.

Furthermore, SBEMU/VSBHDA requires EMM (specifically JEMM or QEMM) because of port trapping, making games using unreal mode and certain protected mode extenders being unable to run. Most won't notice it, but it will be impactful if they play one of these.

theelf wrote on 2024-05-11, 22:03:

ISA is a must for DOS compatibility, even best PCI cards have much lower compatibility. Did not tested SB Link in my life yet

I've done some testing with the ESS Solo-1 on a few platforms. It has generally good compatibility. Most of the issues I ran into are either with problematic games (e.g. Tyrian) or due to speed sensitivity which isn't exclusive to the Solo-1.

ESS Solo-1 DOS Compatibility Testing on Multiple Systems

Sombrero wrote on 2024-05-11, 17:06:

About an year ago I did some testing about that, some of what I remember finding: […]
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Shponglefan wrote on 2024-05-11, 16:36:

Do you have any examples of games that cause stuttering or other issues with ACPI or ODCM throttling?

About an year ago I did some testing about that, some of what I remember finding:

Weird waviness in speed, going from fast to slow to fast again:
- Syndicate (game not CPU speed sensitive so doesn't need ACPI throttling)
- The Incredible Machine
- Tyrian (game not CPU speed sensitive so doesn't need ACPI throttling)

Random stuttering:
- Doom (if throttled beyond certain point but not so much it otherwise affects game speed, also not CPU speed sensitive so doesn't need ACPI throttling)
- Mortal Kombat (IIRC only happened between fights when the next opponent was shown)

I feel like there were more. The games that had that odd waviness could be seen from a mile away, but the ones with random stutters weren't as easy. I remember listing games as being ok with ACPI throttling only to notice later they actually were not ok.

Interesting, I hadn't been testing any of these throttling methods on non-speed sensitive games. As you say, it's a bit moot if the game works without throttling to begin with.

I do plan to continue my testing and hopefully start a thread with some detailed reports on this.

Gmlb256 wrote on 2024-05-11, 22:11:

My experience with non-ISA sound devices in DOS is hit and miss.

Furthermore, SBEMU/VSBHDA requires EMM (specifically JEMM or QEMM) because of port trapping, making games using unreal mode and certain protected mode extenders being unable to run. Most won't notice it, but it will be impactful if they play one of these.

Oops, but you don't know my invention, the false EMS, starts as if it were there, but the full-time exit, as if it were XMS, behaves ... but the XMS/EMS specific code also runs.