Is my Turbo 040 33mhz or 40mhz?

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iamdigitalman's picture
Joined: Mar 2 2004
Posts: 629

Hi guys. In a recent conquest, I got a Mac II (regular II, no letter afterwords), and a Turbo '040 card. No adapter, so I can't test it. The chip is marked XC68040RC33M, and from what I have read, it's a full 040, running at 33mhz. However, it has a oscillator (silver rectangular object next to CPU), marked 20.000000mhz.

According to this, if it were running at 33mhz, it would have a 16.5mhz oscillator. They say a 20mhz one makes it run at 40mhz.

Just want to get my facts straight about it.

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Jon's picture
Joined: Dec 20 2003
Posts: 2804
There's a good chance it's a

There's a good chance it's a 33MHz part overclocked to 40MHz.


I am not in this world to live up to other people's expectations, nor do I feel that the world must live up to mine. - Fritz Perls

Joined: Jul 9 2006
Posts: 61
I think they just overclocked

I think they just overclocked 33's to 40 since the 40's were rare (only the 840av used them and Apple probably had 1st pick).