VOGONS


486sx and 486dx

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Reply 20 of 27, by derSammler

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Yes, that would make sense. But then the jumper selects which CPU to use, and not really if an FPU is present. 😀

Reply 21 of 27, by Scali

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derSammler wrote:

Yes, that would make sense. But then the jumper selects which CPU to use, and not really if an FPU is present. 😀

Well, I think that's a given... The FPU is internal, so only the 486 chip used determines whether the FPU is present or not 😀
I don't think it's possible to disable the FPU in a 486DX externally.

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Reply 23 of 27, by RobertJ

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Scali wrote:
badmojo wrote:

Never heard if any game taking advantage of it, could you provide an example?

Falcon 3.0 had an enhanced mode if you had an FPU.

That's the one I was specifically thinking about. It was one of my favorite flight sims of that era, and the reason I upgraded to a DX at the time.

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Reply 24 of 27, by Baoran

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This is almost same as the motherboard I have: http://stason.org/TULARC/pc/motherboards/D/DT … -PKM-0037S.html

One of the differences is that one of the jumpers that is suppose to tell the cpu type to the motherboard is missing.

The attachment 20180202_153440.jpg is no longer available

As you can see where the JP27 is suppose to be, there is no jumper.
Another difference is that there is winbond chip where it says "real time clock" in the picture and there is a barrel battery next to the keyboard connector.

Reply 25 of 27, by vladstamate

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Another software I used a lot that required FPU was VistaPro. I still have that installed on all my retro PCs starting from 386 to Pentium III. Very fun software to play with.

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Reply 26 of 27, by Baoran

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Quake benchmark works 3.8 fps no matter how I set the jumpers, so no idea what the jumpers actually do.

Reply 27 of 27, by Scali

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Baoran wrote:

Quake benchmark works 3.8 fps no matter how I set the jumpers, so no idea what the jumpers actually do.

Perhaps it's just to set the correct CPU model at the BIOS POST screen?
Does it change from SX to DX?
Perhaps you could also try running some CPU info software from Norton or such, which try to determine the CPU type independently, and see if they change based on the jumpers?

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