It says the turbo button will not work in protected mode. The solution then is to use real mode applications when you want to activate the turbo button.

Interesting topic! I wonder if "protected mode" refers to 32bit protected mode only (with or without V86).
Or 286 protected mode also, as Windows 3.1 does in Standard Mode or OS/2 1.x..

I came up with this awhile back. Much of it is derived from slower or faster actual results, some of it is taken from Phil's VGA Database, and some of it is from my own actual results. It's not perfect, but it can give you a ballpark estimate.

If you run Doom, that will give you one more data point. But when you're trying to peg slowed-down performance, it's never going to be completely consistent. Some benchmarks will say it's much faster, others will say it's slower. You just have to play a few games and get a feel. Wing Commander plays perfectly on a 33Mhz 386, Ultima VII plays perfectly on a 486/33, so that might help you.

Regarding having to reboot for Turbo, that's not the case on my 486. I can turn it on and off while 3dbench (or any game) is running, and see it slow down and speed up.

There are many implementations of Turbo usage. It can be done realtime using the Turbo header or a keyboard combination if the board allows. Sometimes, the BIOS has this functionality, too. But this obviously requires a reboot.

I've seen the Real Mode requirement when a keyboard combination is required, but this didn't require a reboot. I don't have the OPs board, so it could be a specific implementation that adjusts a BIOS setting or something similar.

Finding out exactly what the Turbo implementation is doing can be difficult. And benchmarks can report unusual FSBs and clock speeds. I just use Norton Sys Info or Speedsys to give equivalent CPU speeds, but this can be slightly off.

It is also not limited to socket types, as it can be done even on Socket 7. I haven't seen an implementation on anything newer.

j^aws wrote:

There are many implementations of Turbo usage. It can be done realtime using the Turbo header or a keyboard combination if the board allows. Sometimes, the BIOS has this functionality, too. But this obviously requires a reboot

Actually, my board has all three. It has a BIOS option, a Turbo header and (according to manual) a shortcut. Ctrl+Alt-/+. However, while the turbo works (with a reboot), the shortcut doesn't seem to. Itried it in Wing Commander 1 (a real mode game, I believe). What would be a point of having a shortcut if there is no way to use it on a working machine?

^^ This behaviour doesn't seem right. Try changing the BIOS, either upgrading or downgrading it, and see if that changes how the Turbo works. I also have a board that has all three ways for Turbo activation, but only the BIOS option requires a reboot. The keyboard shortcut is realtime and only works in Real Mode, whilst the Turbo header works in all modes.

So, a quick update. First, I did not realise that the manual refered to + and - on a NumPad. I've launched Norton System Information 8.0 and tried pressing shortcuts. They produced two different kinds of beeps via PC speaker, and the score dropped for a second from 190 to almost 80. The shortcuts don't do anything in Wing Commander.