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First post, by C0deHunter

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Hello all,
I have an ASUS P5A Super7 Motherboard, and recently acquired an odd Pentium 75MHz CPU (A5013718CB - A80502-75 SX969). I am attempting to set the correct jumpers for the Front side, BUS , and Voltage, therefore I need your assistance:

- According to CPU-WORLD.COM, the Intel 75MHz seem to support 3.135V (MIN) / 3.3 V / 3.6 V (MAX) voltage

- It also seems to have a 1.5X Clock Multiplier

https://www.cpu-world.com/sspec/SX/SX969.html
https://www.cpu-world.com/CPUs/Pentium/Intel- … 0A80502-75.html

Other option (if I can not set the exact settings for 75MHZ frequency / 50MHz BUS), would be to maybe down-clock it to a 60 / 66MHz speeds?

Many thanks in advance!

PIII-800E | Abit BH-6 | GeForce FX 5200 | 64MB SD-RAM PC100 | AWE64 Gold | Sound Canvas 55 MKII | SoftMPU | 16GBGB Transcend CF as C:\ and 64GB Transcend CF D:\ (Games) | OS: MS-DOS 7.1-Win98SE-WinME-Win2K Pro (multi-OS menu Using System Commander 2K)

Reply 1 of 6, by melbar

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C0deHunter wrote on 2021-05-29, 11:20:

Other option (if I can not set the exact settings for 75MHZ frequency / 50MHz BUS), would be to maybe down-clock it to a 60 / 66MHz speeds?

60 / 66MHz speeds means overclocking , not downclocking.

This super socket 7 board is quite new compared the "old" pentium 75.

Yes, socket 7 boards are backward compatible to run a socket 5 also.

In this case, you can clock to a P90 (1,5 multi , 60 FSB) so it's overclocked.

See here the link to toms hardware:
They say: "P75 most of them run at least flawlessly at 90 @ 1.5 x 60 MHz, many of them at 100 @ 1.5 x 66 MHz."

Overclocking The Intel Pentium

But i would take care with the heat and would use a better cooler...

Last edited by melbar on 2021-05-29, 11:40. Edited 1 time in total.

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Reply 2 of 6, by C0deHunter

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I see, thanks for the comments. So apparently there is no way that I can get to its manufactured 50MHz BUS speeds, it seems. 🙁

So for the jumper settings, I would set them like these then? (please see attached images)

PIII-800E | Abit BH-6 | GeForce FX 5200 | 64MB SD-RAM PC100 | AWE64 Gold | Sound Canvas 55 MKII | SoftMPU | 16GBGB Transcend CF as C:\ and 64GB Transcend CF D:\ (Games) | OS: MS-DOS 7.1-Win98SE-WinME-Win2K Pro (multi-OS menu Using System Commander 2K)

Reply 3 of 6, by melbar

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Yes , this is the correct setting at pentium P54C 90Mhz.

You can set the vcore to 3.3 , 3.4 or 3.5 volt.
I would start with 3.3V and then have a look if everything is stable. Also take care to the cooling.

EDIT:
Anyway, you can try different speed levels with L1 and /or L2 cache disable setting.

#1 K6-2/500, #2 Athlon1200, #3 Celeron1000A, #4 A64-3700, #5 P4HT-3200, #6 P4-2800, #7 Am486DX2-66

Reply 4 of 6, by BitWrangler

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melbar wrote on 2021-05-29, 11:36:
See here the link to toms hardware: They say: "P75 most of them run at least flawlessly at 90 @ 1.5 x 60 MHz, many of them […]
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See here the link to toms hardware:
They say: "P75 most of them run at least flawlessly at 90 @ 1.5 x 60 MHz, many of them at 100 @ 1.5 x 66 MHz."

Overclocking The Intel Pentium

But i would take care with the heat and would use a better cooler...

Every C2 stepping I've had would at least do 120, E0 are solid at 133, hot at 150 and you can find some that do 166, provided you're using a K6-2 sized heatsink and not one of those little pathetic 1cm high ones that P75s might have been blessed cursed with "stock"

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Reply 5 of 6, by C0deHunter

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Thank you so much for informative responses! OK, I managed to change the jumpers and everything seems to be working great, *except* that I get an error during BIOS boot, stating that there is voltage issue:

Per your suggestions, I am using the middle-ground 3.3 V VID, and the CPU came with a very large passive heath-sink, so I know it stays cool enough.

Please see the attached image.

PIII-800E | Abit BH-6 | GeForce FX 5200 | 64MB SD-RAM PC100 | AWE64 Gold | Sound Canvas 55 MKII | SoftMPU | 16GBGB Transcend CF as C:\ and 64GB Transcend CF D:\ (Games) | OS: MS-DOS 7.1-Win98SE-WinME-Win2K Pro (multi-OS menu Using System Commander 2K)

Reply 6 of 6, by C0deHunter

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UPDATE:
I loaded up the BIOS default settings, and the error message is gone, as it turned OFF all the settings for the ** VOLTAGE Monitor ** entry!!!

PIII-800E | Abit BH-6 | GeForce FX 5200 | 64MB SD-RAM PC100 | AWE64 Gold | Sound Canvas 55 MKII | SoftMPU | 16GBGB Transcend CF as C:\ and 64GB Transcend CF D:\ (Games) | OS: MS-DOS 7.1-Win98SE-WinME-Win2K Pro (multi-OS menu Using System Commander 2K)