I was wondering if the main mosfet voltage goes also to the single JP11 vcore jumper and the different position increase more or less voltage to the cpu, if the voltage is read 2,43v without that jumper what would happen theorically (!) with two jumpers installed? More or less voltage or maybe not even designed for it?

From the manual: the cpu voltage core jumper is the JP11 (the single one on that multiple jumper couples of pins close to the mosfet). Behind the mosfet there's a Bus Voltage jumper (I/O) (1-2 or 2-3 position) that seems like 3,5v or 3,3v. The other four red jumpers that are seen above the right corner socket are again for the Bus with those four jumpers to 1-2 for the newer cpu (dual voltage I suppose) or all four to 2-3 for the older Pentium/K5.
What about the bios, considering is a middle 1997 bios, would recognize a K6-2 or K6-3 without having a bios update maybe reading some generic K6 processor?

Also there're two jumpers that are factory reserved:

"JP36, JP37 - Reserved Jumpers
Reserved jumpers are pre-installed in the factory. They should NOT be altered by the users."

Sometimes one of the non listed positions activate a lower voltage tier.

You would normally have a jumper position for +0.1v, +0.2v, +0.4v, +0.8v

Usually the mmx setting is the +0.8

But obviously, your board is not like this

Adding more than one jumper can get you combos.

If you have a lower tier setting sometimes +0.1 becomes +0.05, +0.2 becomes +0.1 and so on (50%)

Usually they are all in a neat little row.

Doesn’t mean yours is the same. Yours could be very different.

Sphere478 wrote on 2022-01-30, 12:35:

Sometimes one of the non listed positions activate a lower voltage tier. […]
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Sometimes one of the non listed positions activate a lower voltage tier.

You would normally have a jumper position for +0.1v, +0.2v, +0.4v, +0.8v

Usually the mmx setting is the +0.8

But obviously, your board is not like this

Adding more than one jumper can get you combos.

If you have a lower tier setting sometimes +0.1 becomes +0.05, +0.2 becomes +0.1 and so on (50%)

Usually they are all in a neat little row.

Doesn’t mean yours is the same. Yours could be very different.

Understood, meanwhile I've seen there was another mosfet on the back of the heatsink I didn't notice before I suppose for the dual voltage P-MMX logic. I would measure what happen with adding another jumper but I would not like to break something, maybe the mosfet who knows. The other jumpers seems not to help, the JP6 doesn't change voltages only probably the multiplier. Those two reserved jumpers might be interesting but I don't know really what might happen changing it. Anyway with a minimun 2,42 volt (it'd be interesting under cpu load if the voltage changes, increase or decrease) which options I have, the K6-3 400 2.4v (that I have)?. But the bios how would work with it and its internal cache?

After the K6-3 I've found I also have a K6-2 450AHX with 2.4v voltage. Should I try these?

Update: the K6-2 450AHX without voltage jumper so it should work around its voltage 2,4v is seen as 486DX @ 66Mhz..on a Socket 7.. 😁

Why it even had the string 80486DX into the bios I don't know.. anyway I don't know how this is going to work if a K6-2 processor isn't even listed in the bios. I suppose it might need a patched bios to see any newer cpu, cause the K6-266 maybe might work with the JP6 multiplier but the +0,2 volts seems too much and I don't know..

Update2: The K6-3 400 2,4v is seen equally as 80486DX but the CPUid tool at cd boot see it as K6 3D+ Processor @ 400,898Mhz 256Kb cache and all the flags even the 3dnow. Are there any possibility that without the voltage vcore jumpers the PCI cards might work not correctly? Memtest also is running seeing the cpu as K6 3D+ 400,9Mhz and the L2 256k cache @ 104MB/s. The L3 cache of the mainboard is not seen probably I suppose it'd be even better to disable it by the bios.

Ok, the Win 98 o.s. see it as AuthenticAMD AMD K6(tm) 3D+ Processor / Intel MMX Technology.. some syntethic bench mostly similar result of the K6-2 400. Too bad for the inital cpu bios detect string but seems like it works even if maybe at this cores voltage limit. And the mosfet heatsink temp seems quite high. Power current at the wall also is a bit high closer to 90 watts totally.
I was thinking to see improvements with the Rage Pro PCI but seems mostly resulting with the same 3D speed.. I suppose is the video card that is slow cause the 3DMark99 CPU Marks are like 3 or 4 times the P-233 ones with the 3DNow! enabled.

386SX wrote on 2022-01-30, 13:10:

After the K6-3 I've found I also have a K6-2 450AHX with 2.4v voltage. Should I try these?

A k6-3 should be fine at 2.4v

Slowest clock per clock
K6-2
K6-2+
k6-3
k6-3+
Fastest clock per clock

Bios seeing it as a 486 is normal. Just means the bios isn’t up to date.
DIY Bios Modding guide Jan Steunebrink k6-2+/3+ 128gb

It’s normal for memtest to not show the mainboard cache when k63/+ is installed. It should be working though.

The K6-2 is gonna be at least a .5 multi behind the III, so really only run a 2 in favor of a III if you can get it running 100mhz faster... which does happen. However, you're unlikely to get a plain 2 running faster than a 2+ or 3+ unless you've got a spectacularly good one and a spectacularly bad one. 2+ is only a few percent behind a III or a 3+ so maybe favor those if they go 50Mhz faster... though at the top end some weird stuff happens with multis and bus speeds where you might get a better result a little slower. Might be due to kicking in more wait states or something. Need to mess around with various bus speeds and multis within the top 100 mhz of what it will do to figure it out. I don't actually know if it will be a different sweet spot for III, 2+ and 3+

Thanks, I'll try the bios modding eventually to make it dectect the right cpu at boot that it's not great to read and also the hard disk size patch, beside until now I'm still using a time correct 4,3GB IDE disk. It's impressive anyway how much could these board be upgraded. It's not like the P-MMX 233 isn't capable of running Win 98 at a good speed when instead probably after the patches and updates the ram size theorically is more limiting the speed with the 64MB I've got now while 128MB with double side DIMMs should be possible maybe, anyway 2x32MB PC66 seems like a more balanced amount even for the K6-III. I expected the Rage Pro PCI to be faster than it is, there's quite a difference from the same chip on the AGP bus of the "Turbo" model and I don't think the bus was a bottleneck.