I did a little test with my Cyrix 5x86-133 to verify the CLK register selection. I used chkcpu (16-bit) to verify the core frequency and Maxspeed as a secondary backup.
I was able to switch from 4x to 2x to 1x, then back to 2x, 1x and 4x, however, when I set it from 1x to 3x, the frequency actually only went to 2x according to chkcpu.
The wording of the cyrix literature is a little ambiguous, but it that seems after you boot-up and if you start out at 4x, for example, you can switch between 1x, 2x, and 4x. If you start out at 3x, you can switch between 1x and 3x. If you start out at 2x you can switch between 2x and 1x. If you start out at 1x you can transition to either 2x or 3x, but once you go up to 3x, you can only go back down to 1x, and if you decide initially to bump up to 2x, you cannot go to 3x until you reboot with 1x.
FYI, chkcpu tends to thinks the multiplier is still at 4x when I dropped the multiplier 2x and incorrectly reports, for example, 67 Mhz, 4x, 16.7 FSB.
For your case then, you'd want to start out at 1x, and once booted, set the register to 3x. The problem you may run into is that your BIOS/motherboard may only have a 1-bit CLKMUL, meaning that if you set it to 1x, the Cyrix will want to run at 3x, and if set to 2x, the Cyrix will run at 2x.
Have you been able to boot with a 1x setting at 33 MHz?
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