This board has an i440ZX chipset, which is a cut-down i440BX with half the memory capability. Otherwise it's the same.

For Slot 1 CPU support, three things are relevant:
- voltage support
- BIOS support
- FSB speed support

Multiplier is irrelevant as (unless you have an engineering sample) it's locked and the CPU will ignore whatever the motherboard does or doesn't indicate.

For voltage, and assuming 100MHz FSB P2/P3 CPUs are good, the distinction is between min 1.8V Deschutes/Katmai cores and min 1.6V Coppermine cores. Big question here is which P3-500 you have, a P3-500 (no additional letter), i.e. Katmai, or a P3-500E, i.e. Coppermine. If it's a Coppermine your board can deliver the correct voltage for with any Coppermine CPU up to 1100MHz. That does not tell you whether it can supply the required current for a faster CPU though. If it's Katmai, it might be able to do the voltage, but it might not. The manual is pretty useless to determine. What would be useful to find this out which voltage regulator chip your board has. Looking at this picture it's the little rectangular chip above the DIMM slots and to the right of the i443BX northbridge, just below two MOSFETs. Read the chip code of that regulator, and we can find out what voltages it supports and which current it is rated for.

If it can't do required voltage and current, you're out of luck.

If it can do the required current, but not the voltage, inserting an unmodified Slot 1 Coppermine CPU will result in no boot, as the VRM will not deliver any power if the CPU asks for a voltage it can't deliver. Instead you could consider an So370 Coppermine CPU on a Slocket Socket-to-slot converter with voltage jumpers. This does not actually change the voltage, but it instructs the board to deliver 1.8V, which is low enough it won't fry a Coppermine CPU.

If you're good for voltage and current of your chosen CPU or CPU+slocket combo, you're lucky, then move on to the next step - BIOS.

In terms of BIOS, if you're lucky your CPU is supported and all works well. If not, you can get one of three behaviours:
- not recognized, but behaves normally
- not regognized and performance or features compromised
- no boot at all (particularly prevalent on Intel OEM BIOS)

But it looks like you're in luck in terms of BIOS, as the link you give has multiple BIOS files. The latest, 1.17, comes with a whatsnew.txt file that says the following:

Verze 1.17 z 17.10.2000 ----------------------- [+] Pridana podpora Celeronu 633/66 az 766/66 [+] Pridana p […]
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Verze 1.17 z 17.10.2000
-----------------------
[+] Pridana podpora Celeronu 633/66 az 766/66
[+] Pridana podpora Celeronu 800/100 az 900/100
[+] Pridana podpora PIII 750, 800 a 850 MHz
[+] Pridana podpora VIA Cyrix III 500, 533, 550 a 600 MHz.
[!] Porad zde pretrvava chyba DMI BIOSu, kde se deska hlasi
jako typ "CreateBXi-ATX" (viz napr. program HWiNFO)

UPOZORNENI: BIOS 1.17 neoficialne podporuje Celerony az do 1.1 GHz.
Pripadnou problemovou funkci techto rychlych CPU vsak nelze uznat
jako vadu!

Now, my Czech isn't perfect, but this looks like full support for Celeron up to 900MHz, P3 up to 850MHz and C3 up to 600MHz, along with somehting about Celeron 1100 maybe working but not being recognized.

A word of warning:
The important factor in BIOS support isn't the number of MHz but is the stepping of the CPU. This BIOS is dated October 2000, so should be good with any P3/Celeron stepping up to that point. Now, there were four steppings of P3 CPUs, cA0, cB0, cC0 and cD0. CA0 were very early CPUs but are definitely supported, cB0 was released in mid 2000 so should be good too. cD0 was from 2001 and is definitely too late. I'm having trouble pinning down cC0, as it was probably somewhere in late 2000. To be on the safe side, only assume this BIOS supports cA0 and cB0 stepping P3 CPUs. You can identify the stepping by feeding the S-Spec number into the search engine at cpu-world.com. So for example if you want to max this out with P3-850, you can read that there are no cA0 CPUs at that speed and only S-Spec SL43H is cB0. Other S-Specs like SL49G, SL4CC, SL4MC and SL4Z2 are cC0 or cD0. So go for a P3-850 marked SL43H if you want that speed.

And then there's FSB support. You want a P3-733MHz. That's a 133MHz FSB CPU, running at 5.5x133MHz. As your board only does 100MHz unmodifiied, if it runs it will run at 5.5x100=550MHz. Now, possibly the PLL (clock generator) on your board could generate 133MHz, in which case you can try overclocking using software (SoftFSB, CPUFSB etc) - but no guarantees that all the bits if your board will be happy with that. So if you want to play it safe, choose a CPU with 100MHz FSB, i.e. a CPU with a model number ending in "E" instead of "EB" (the "B" implies 133MHz FSB)

Thank you for your reply.

The CPU i'm using is this one: https://www.cpu-world.com/sspec/SL/SL37D.html

Regarding the chip:

Vaylo wrote on 2024-11-19, 12:39:

Thank you for your reply.

The CPU i'm using is this one: https://www.cpu-world.com/sspec/SL/SL37D.html

Katmai. So doesn't say anything about Coppermine voltage.

Regarding the chip: […]
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Regarding the chip:

Datasheet: https://www.alldatasheet.com/datasheet-pdf/vi … /LX1665CDW.html

The main output is adjustable from 1.3V to 3.5V using a 5-bit code.

Looking good. Table 1 on page 4 corresponds exactly to Intel's VRM 8.3 spec.

So provided the board actually connects the VID 0, 1, 2 and 3 pins on the CPU to this chip, it should output whatever voltage is needed.

In terms of current the chip itself is fine, with an application example of a Pentium II CPU that needs 14.2A. Whether the board can deliver that depends on the circuitry around it. A p3-850E draws 25.7W at 1.65V-1.75V, so worst-case (1.65V) it needs 16.6A. If you want to stay under 14.2A for safety's sake and you have a 1.65V Coppermine CPU, you can draw max 23.43W, which means a P3-800E is the fastest safe P3. The same applies to Coppermine Celeron chips too, max 800MHz to stay under 14.2A.

Then again, that's just an example. The datasheet gives formulae to calculate what is needed for a given application, so by feeding in the component values you can determine exactly what your board can handle. But if you want 733MHz, you could do a P3-700E or P3-750E (or take a P3-933EB or P3-1000EB and run them at 100MHz FSB for the same effect).

Thank you very much for your comprehensive answer. Much appreciated 😀