im not sure these boards did check the cpu on boot, you probably have to set it up correctly

Likely some jumpers that need to be configured on the motherboard to change multiplier and FSB. Your 120 is 60Mhz x 2; the 166 should be set to 66Mhz x 2.5. So there will probably be a group of jumpers that control the FSB that would have to be changed from 60 to 66, and a group of jumpers that control the multiplier that will need to be changed from 2.0 to 2.5.

You motherboard may have these settings screenprinted on, or if not, you'll have to find a manual for your specific model. If you need help, you can post the motherboard model here.

11justsomekid wrote:

Next, I decided to update my CPU, from 120mhz to 166 (the max for my motherboard).

Technically, both socket 5 and 7 motherboards can support all intel CPU frequencies as long as CPU fit the socket. You probably have a regular dual voltage socket 7 motherboard, which officially should take Pentium MMX 233MHz as max.

Original Pentium motherboards do not check the CPU themselves, the rely on jumpers to set the bus frequency, multiplier and voltage. Because of that, even a Pentium 200 can be run as Pentium 75 and will be "detected" as Pentium 75 by the BIOS.

In your case, Pentium 120 = 60x2 where 2 is the multiplier and 60 is the bus frequency. Pentium 166 = 66x2.5. The voltage should be the same.

So there are two ways to change the jumpers:

1) look up the manual for your board;
2) the proper settings are usually silkscreened on the board itself, and you should just look for the FSB and multiplier values I've mentioned.

Well, there were jumpers! I had the manual already, but the jumper diagrams were in the back, so I couldn't see them with the other installation stuff.

SSTV2 wrote:

11justsomekid wrote:

Next, I decided to update my CPU, from 120mhz to 166 (the max for my motherboard).

Technically, both socket 5 and 7 motherboards can support all intel CPU frequencies as long as CPU fit the socket. You probably have a regular dual voltage socket 7 motherboard, which officially should take Pentium MMX 233MHz as max.

Since it goes out of its way to say it has a max of 166 (no jumper settings above), and the MMX had already been introduced when the motherboard was released, I would rather have the max settings the computer was built for. I know that the 233 is about the same price as the 166, but I didn't know if it would like it being there. If it could take it, why set a maximum?

11justsomekid wrote:

Well, there were jumpers! I had the manual already, but the jumper diagrams were in the back, so I couldn't see them with the other installation stuff.

SSTV2 wrote:

11justsomekid wrote:

Next, I decided to update my CPU, from 120mhz to 166 (the max for my motherboard).

Technically, both socket 5 and 7 motherboards can support all intel CPU frequencies as long as CPU fit the socket. You probably have a regular dual voltage socket 7 motherboard, which officially should take Pentium MMX 233MHz as max.

Since it goes out of its way to say it has a max of 166 (no jumper settings above), and the MMX had already been introduced when the motherboard was released, I would rather have the max settings the computer was built for. I know that the 233 is about the same price as the 166, but I didn't know if it would like it being there. If it could take it, why set a maximum?

Which board (and revision) is it? And how many multiplier jumpers are there?

The very first So7 boards had a single jumper for 1.5x or 2x (so 75-133MHz), if you can set 2.5x (i.e. 166MHz) that means you have at least two jumpers, which gives you four options: 1.5x, 2x, 2.5x and 3x. So even if the 3x setting is not documented, it's there. For 3.5x, Intel recycled the 1.5x setting. The P54C (Pentium non-MMX) reads it as 1.5x, the P55C (Pentium MMX) reads it as 3.5x. In other words, any board that has a setting for 166MHz can also do 200 and 233MHz with a suitable CPU. With a third multiplier jumper, you can also set 4x, 4.5x, 5x and 5.5x. When AMD introduced the K6-2 they needed a 6x multiplier, but So7 only specifies 3 multiplier pins. So AMD recycled the 2x setting, with the K6-2/3(+) reading that as 6x. Consequence is that a K6-2 can run at 400MHz (6x66MHz) on any So7 board - providing the board can supply the correct voltage.

That - and not the multiplier setting - is the real challenge. If your board supports split voltage (3.3VIO, 2.8V or lower VCore) you can use the P55C (MMX) - at any speed - but if it's an old single voltage design you can't.

dionb wrote:

Which board (and revision) is it? And how many multiplier jumpers are there?

The very first So7 boards had a single jumper for 1.5x or 2x (so 75-133MHz), if you can set 2.5x (i.e. 166MHz) that means you have at least two jumpers, which gives you four options: 1.5x, 2x, 2.5x and 3x. So even if the 3x setting is not documented, it's there. For 3.5x, Intel recycled the 1.5x setting. The P54C (Pentium non-MMX) reads it as 1.5x, the P55C (Pentium MMX) reads it as 3.5x. In other words, any board that has a setting for 166MHz can also do 200 and 233MHz with a suitable CPU. With a third multiplier jumper, you can also set 4x, 4.5x, 5x and 5.5x. When AMD introduced the K6-2 they needed a 6x multiplier, but So7 only specifies 3 multiplier pins. So AMD recycled the 2x setting, with the K6-2/3(+) reading that as 6x. Consequence is that a K6-2 can run at 400MHz (6x66MHz) on any So7 board - providing the board can supply the correct voltage.

That - and not the multiplier setting - is the real challenge. If your board supports split voltage (3.3VIO, 2.8V or lower VCore) you can use the P55C (MMX) - at any speed - but if it's an old single voltage design you can't.

My motherboard is a P/I-p55tp4n. I didn't know what I was doing; still learning!

dionb wrote:

In other words, any board that has a setting for 166MHz can also do 200 and 233MHz with a suitable CPU.

Yes, except both the K6-2 or newer and the P55C require split plane I/O and core voltages. Older socket 7 boards sometimes used a common voltage for both.

FSB and multiplier jumpers

Unfortunately, this motherboard can only support a Pentium P54 core, not a Pentium MMX or an AMD k6-2. Anything more would require an on socket voltage adapter (including the Overdrive MMX) or motherboard surgery to install a switching regulator.

gdjacobs wrote:

dionb wrote:

In other words, any board that has a setting for 166MHz can also do 200 and 233MHz with a suitable CPU.

Yes, except both the K6-2 or newer and the P55C require split plane I/O and core voltages. Older socket 7 boards sometimes used a common voltage for both.

Which I already said was the bigger problem than the multipliers 😉

Single voltage means either P54C or overdrive-type stuff.

FSB and multiplier jumpers http://i.imgur.com/T8JUtlH.png […]
Show full quote

FSB and multiplier jumpers

Unfortunately, this motherboard can only support a Pentium P54 core, not a Pentium MMX or an AMD k6-2. Anything more would require an on socket voltage adapter (including the Overdrive MMX) or motherboard surgery to install a switching regulator.

Yep. This is a nice vintage i430FX board, great by 1996 standards, but it's not going to run the later So7 stuff.

The fastest non-MMX P54C runs at 200MHz, that would definitely be possible here. Making a single-voltage board split voltage would require more surgery than just a switching regulator - it would also require isolating core and IO sections from each other, which I'd generally consider hardly possible (unless it was designed split voltage in mind, which this board wasn't).

So your only faster options would be Overdrives or Evergreen or Powerleap's variants. Worth a laugh if you happen to find one, but given the other limitations of the board/chipset not really worth it. Better to just stick to P54C with this one and get something more 1998-ish if you want the later So7 stuff.

I run a Pentium Overdrive 200MMX in a Packard Bell that otherwise maxes out at P54C and it's a great cpu. It supports setmul's test register switches, so it is very configurable at various speeds. Including being able to run Ultima VII: The Black Gate. Normally, this game re-enables caches when disabled to slow down enough to play the game at a normal speed. But by using the DCD test register, the cpu runs at slow 486 speeds and makes the game very playable. And by disabling all caches, the cpu runs at 386DX-25 speeds, so games like Wing Commander run well too. If that sort of thing is important to you, as well as having a little extra speed from the MMX instructions for more demanding DOS games, it might be worth hunting one of these down.

*GULP*
https://www.ebay.ca/itm/New-Sealed-Intel-Pent … yvMAAOSwO9JZ~J1~

There's also this, although I'm not familiar enough with socket 7 voltage adapters to know if this particular design has any problems.
https://www.ebay.ca/itm/Vintage-Intel-Pentium … UEAAOSwTLxZh76E

gdjacobs wrote:

*GULP*
https://www.ebay.ca/itm/New-Sealed-Intel-Pent … yvMAAOSwO9JZ~J1~

If you're patient, you could get a much better deal. I got mine for around $30. The guy who was selling it wasn't sure exactly what speed it was, but the integrated HSF made it obvious it was a P55C overdrive. I took a chance and the rest is history.
Cheapest one I could find at the moment is $48US plus $13 shipping:
https://www.ebay.com/itm/Intel-SL2RM-Pentium- … hEAAOSw3R1XTzh2

That's a lot more like it!

dionb wrote:

Which I already said was the bigger problem than the multipliers ;) […]
Show full quote

gdjacobs wrote:

dionb wrote:

In other words, any board that has a setting for 166MHz can also do 200 and 233MHz with a suitable CPU.

Yes, except both the K6-2 or newer and the P55C require split plane I/O and core voltages. Older socket 7 boards sometimes used a common voltage for both.

Which I already said was the bigger problem than the multipliers 😉

Single voltage means either P54C or overdrive-type stuff.

FSB and multiplier jumpers http://i.imgur.com/T8JUtlH.png […]
Show full quote

FSB and multiplier jumpers

Unfortunately, this motherboard can only support a Pentium P54 core, not a Pentium MMX or an AMD k6-2. Anything more would require an on socket voltage adapter (including the Overdrive MMX) or motherboard surgery to install a switching regulator.

Yep. This is a nice vintage i430FX board, great by 1996 standards, but it's not going to run the later So7 stuff.

The fastest non-MMX P54C runs at 200MHz, that would definitely be possible here. Making a single-voltage board split voltage would require more surgery than just a switching regulator - it would also require isolating core and IO sections from each other, which I'd generally consider hardly possible (unless it was designed split voltage in mind, which this board wasn't).

So your only faster options would be Overdrives or Evergreen or Powerleap's variants. Worth a laugh if you happen to find one, but given the other limitations of the board/chipset not really worth it. Better to just stick to P54C with this one and get something more 1998-ish if you want the later So7 stuff.

I don't think I'll do any surgery anytime soon. I barely have soldering down, let alone with tiny components. I kind of wanted a nice maxed out 1996 PC. If I need later stuff, I'll go for a Pentium iii or something like that. By the way, what are the Evergreens and Powerleaps? I've never heard of them.

> what are the Evergreens and Powerleaps?

These are socket upgrade adapters. Make possible to run newer cpus on older motherboard.

kixs wrote:

> what are the Evergreens and Powerleaps?

These are socket upgrade adapters. Make possible to run newer cpus on older motherboard.

Woah, didn't even know that was possible! Is there a thread that discusses this somewhere?

Here's an interesting thread where someone used a socket adapter to make a particularly crazy machine.
WIP 2: The 6-in-1 Turbo-switched Socket 7 - from XT to 500MHz; dual Tseng powered...