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Pentium 90 (P54C) multiplier modification?

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#1 trodas


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Posted 27 February 2009 - 08:47 AM

An old Pentium 90 CPU (P54C) has internal multiplier x1.5 - so it make from the 60MHz FSB the 90MHz clock.

I do wonder, however, if that multiplier can be set to x1 :thumbsup:

Usually people want to overclock, however I would like to try underclocking and the x1.5 multiplier suxx. If I understand good the multiplier settings, for example for the Asus TXP4-X Socket 7 board: http://rapidshare.com/files/202992710/Asus_TXP4-X.pdf
( http://capsmod.net/forum/viewthread.php?tid=342 )
Then setting BF0, BF1 to 1-2, 1-2 (manual, page 17) let the CPU internal multiplier be used, so, if I can modify the multiplier somehow (burning internal path? connecting two pins?), then I got the underclocker dream machine.

Anyone know if that is possible or know someone who might know?

Another possibility is the Pentium Overdrive, but dunno where to obtain one and if it ever run at x1 multi. Any other ideas, beside rare 5V Pentium 60/66 witch use Socket 4 and hence are not very usufull as the nice underclocker board has Socket 7 (5) ...

Another idea pop into mind and that is the Mobile Pentium or Mobile Pentium MMX chips for laptops, but I have no idea either where to get one of these, besides I have no idea if they can run with the x1 multi... :flowers:

Anyone got some clues there?

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#2 dpunisher


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Posted 27 February 2009 - 10:13 AM

Can you change the jumpers for memory clock and underclock that way?

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#3 skiplc


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Posted 27 February 2009 - 03:25 PM

Is the Asus TXP4-X the motherboard you're using now? If not, what is the exact model and version of your motherboard?

I don't recall a Socket 7 board with a 1x multi as there was no need for 1x. The slowest Socket 7 chip I know of was a 75Mhz P54C running at 50x1.5.

Pentium Overdrive if you mean the POD or DXODP stuff were, afaik, all socket 1.2.3 and a few socket 4 chips.

I'll look through a stack of Socket 7 boards I'm tossing today and see if any offer 1x.

6:15 Edit

I looked over about a dozen Socket 7 boards this afternoon. Slowest FSB was 50Mhz and smallest multiplier was 1.5x.

Edited by skiplc, 27 February 2009 - 09:15 PM.

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