VOGONS

Question about coprocessors

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First post, by kalgon

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I recently got myself an AST Bravo 386SX20 PC and noticed that there was an empty slot for a coprocessor.

386SX20.jpg

I found the following coprocessor in a pile of hardware but the big 25 on it seems to indicate that it is suitable for an SX25.

387SX25.jpg

Is it safe to use it on this PC or do the CPU and coprocessor frequencies have to be exactly the same?
I'm not very familiar with 386's because at the time I went straight from a 286 to a Pentium without going through the 386 and 486.

Thank you,
Xavier

Reply 1 of 3, by TrashPanda

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Since you already have it, give it a shot it wont hurt anything if it doesnt work, if it works you'll quickly know.

The question is, is its a 487 co processor or a 387 coprocessor, I dont believe a 486 co processor will work with a 386 but I dont have a ton of experience with this.

Last edited by TrashPanda on 2022-02-17, 08:42. Edited 1 time in total.

Reply 2 of 3, by weedeewee

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the computer is running at 20 MHz.
Placing an fpu or even replacing the cpu with one that is rated for a higher speed is no problem at all.

Right to repair is fundamental. You own it, you're allowed to fix it.
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Reply 3 of 3, by dionb

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Speed ratings are like speed signs on the road side: they don't determine how fast you drive, just how fast is safe to do so. Sometimes you can get away with more, but you risk crashing. Less is always safe - and unlike in real traffic there aren't frustrated drivers stuck behind you getting irritated if you go (way) below the limit 😉

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