You don't need Thunderbird. Thouroughbred-B and Barton cores had completely unlocked multiplier up to a certain week of production. Desktop CPUs can go down to 5x multiplier and mobile or modded desktop CPUs (only Athlon XP) can go down to 3x multiplier. So 500 and 300 Mhz respectively. After that you can disable L2 cache and use the Throttle utility.

Disabling L1 cache is counterproductive, because performance drops all the way down to a 386SX 16-20 Mhz level, without any way to negate it.

The Serpent Rider wrote on 2020-01-09, 10:52:

You don't need Thunderbird. Thouroughbred-B and Barton cores had completely unlocked multiplier up to a certain week of production. Desktop CPUs can go down to 5x multiplier and mobile or modded desktop CPUs (only Athlon XP) can go down to 3x multiplier. So 500 and 300 Mhz respectively. After that you can disable L2 cache and use the Throttle utility.

Disabling L1 cache is counterproductive, because performance drops all the way down to a 386SX 16-20 Mhz level, without any way to negate it.

386SX-16/20 level is exactly where I want to go, as I want to build a Duron 1300 DOS PC that can also play speed sensitive games. I'm trying to understand how feasible this is.

The Serpent Rider wrote on 2020-01-09, 10:52:

You don't need Thunderbird. Thouroughbred-B and Barton cores had completely unlocked multiplier up to a certain week of production. Desktop CPUs can go down to 5x multiplier and mobile or modded desktop CPUs (only Athlon XP) can go down to 3x multiplier. So 500 and 300 Mhz respectively. After that you can disable L2 cache and use the Throttle utility.

Disabling L1 cache is counterproductive, because performance drops all the way down to a 386SX 16-20 Mhz level, without any way to negate it.

You can also use socket A Geode CPUs.

appiah4 wrote on 2020-01-09, 10:35:

I guess the answer to this can vary depending on the core in question, but if we stick to the original 100MHz Thunderbird Athlons and Spitfire/Morgan Durons for the sake of argument, how far can the Socket A CPUs be slowed down? How much of it has to be done through BIOS and how much of it can be achieved through software manipulation of the L1 cache etc?

I have had a board that could be slowed down to 50 MHz FSB in BIOS.
Side effect: Massive lower power consumption.

You can also use socket A Geode CPUs

Geode is Thoroughbred-B.

The Serpent Rider wrote on 2020-01-09, 16:07:

You can also use socket A Geode CPUs

Geode is Thoroughbred-B.

Unlocked.

Thoroughbreds are unlocked. It's not that hard to find Athlon XP 1700+ with unlocked multiplier. And most of them are capable to work at 2Ghz (real clock) with stock voltage or 1 Ghz at nearly 1 V.