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First post, by user33331

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For P5I430VX/250
What jumper settings for this board if I use:
-233 MMX.
-K6-1: 233,266,300mhz.
-Is any K6-II or III usable or only Super ?

http://www.elhvb.com/mobokive/Archive/Qdi%20- … ls/430vxe13.pdf
https://stason.org/TULARC/pc/motherboards/Q/Q … 0-EXPLORER.html

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Reply 1 of 4, by Doornkaat

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I can't say for sure unless I had seen the VRM on your board but I'm pretty sure without modifications it won't support anything above a K6 233MHz CPU, maybe less.
It should support the MMX 233 fine but I recommend a cooler that will create airflow over the heatsinked transistors.
Both P1 MMX and K6 will interpret a 1.5x multi as 3.5x so in order to run those at 233MHz use the Intel 100MHz settings (with voltage settings for your CPU of course).

Reply 2 of 4, by dionb

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You're forgetting the most relevant section, the voltages. According to TH99 the board has settings down to 2.5V. That's far too high for K6Plus CPUs, but fine for K6-3 (non-plus) and a bit high but not dangerous if your cooling is decent for K6-2.

If you're trying to use unsupported CPUs, first thing to do is to distill those silly "use these settings per CPU type" tables into the actual multiplier and bus speed settings. Look at P75, P90 and P100. All use 1.5x multiplier, so whatever stays the same across all three is the multiplier. The setting that changes is bus speed. In any event, you have two bits per setting, so BF0 and BF1 for multiplier and 2^2 (4) settings for bus. That's bad news as it means you have 50, 55, 60 and 66MHz only.

Now, all is not lost: K6-2 and -3 400 and higher interpret a 2x multiplier as 6x. So you could run a K6-2 or -3 at 66MHzx6=400MHz, with 2.5V. See TH99 for the voltage setting and see a CPU that does 2x66 in the table you posted for the bus and multiplier settings.

Last hurdle is BIOS. It is highly unlikely there is a BIOS for this board that officially supports K6-2. How non-supportive BIOS react can vary from a correct MHz indication with unknown CPU down to downright refusing to boot. YMMV, just one way to find out.

Reply 3 of 4, by user33331

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Now using P200 mmx. Guess I will settle for it.
- I see a "little foot" K6-I 233 has VCore=2.2V (This board does min.2.5V.)
- Only upgrade option would then be the not so creative solution= 233 mmx.
- If I'm not trying a K6-III 400 to this board.

Ok. At least I tried.
Hope that Matrox G550 32mb PCI will give it a little bit of boost instead of S3Trio64v+ 1\2mb.

Reply 4 of 4, by Doornkaat

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user33331 wrote on 2020-02-12, 05:20:
Now using P200 mmx. Guess I will settle for it. - I see a "little foot" K6-I 233 has VCore=2.2V (This board does min.2.5V.) - O […]
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Now using P200 mmx. Guess I will settle for it.
- I see a "little foot" K6-I 233 has VCore=2.2V (This board does min.2.5V.)
- Only upgrade option would then be the not so creative solution= 233 mmx.
- If I'm not trying a K6-III 400 to this board.

Ok. At least I tried.
Hope that Matrox G550 32mb PCI will give it a little bit of boost instead of S3Trio64v+ 1\2mb.

Don't worry about it, this computer is fine for a lot of DOS games. Being fast isn't all, being reliable and compatible (and in some cases actually being slow) are important virtues as well. For more demanding games I would generally choose another platform than Socket 7. (Even though there are obviously faster S7 configurations.)

The biggest problem shouldn't be voltages but amperage. Your voltage regulation transistor will probably be rated at ~5A. That means with sufficient cooling you may be able to pull a bit more than 7A but that's probably it.
This board has been designed around the power requirements of Pentium and K5 CPUs. With the more power hungry K6(-X) CPUs board manufacturers switched to switching power regulation that is capable of delivering higher currents with lower heat output.
Anyway if you can replace the transistor with a higher rated one and find the correct resistor value to replace the voltage selection jumper with you maybe able to run something like a K6-2 266 on this board.
That is a substantial upgrade over the 200MMX but again in the end you're probably better off running more demanding games on a Slot1 or SS7 based computer.