bloodem wrote on 2025-05-20, 13:12:

PARKE wrote on 2025-05-20, 08:13:

There is one aspect that could be causing problems with this sort of set up. The high-end Coppermines and Tualatins may draw more power (in amps) than what the 8.4 vrm of the motherboard can handle. You can read about it in the second part of this article:
http://www.duhvoodooman.com/powrleap/LFL/Slot-T_1.htm

I confirm, I had the same issue with an Amptron PII-3100 board which refused to work with power hungry Katmai or Coppermine CPUs.
After I replaced the CEB603AL MOSFETs with CEB703AL, the board now works perfectly with any CPU I throw at it, including a P3 Coppermine 1 GHz or a Tualatin 1.4 GHz. So I'm 99.9999% sure that this is also OP's problem.

I appreciate both of you. That may be beyond my abilities at the moment.

What do you suppose the highest I could go without replacing that component would be? Would a slot 1 850MHz Pentium III work without trouble?

Matt The Cat wrote on 2025-05-23, 03:05:

I appreciate both of you. That may be beyond my abilities at the moment.

What do you suppose the highest I could go without replacing that component would be? Would a slot 1 850MHz Pentium III work without trouble?

Very hard to say. Trial and error is the only way to know for sure (as long as you have multiple CPUs to test, which I realize is not the case for many people).
I would first start with a CPU that has a TDP below 20W (something like a Coppermine 650 / 700) and go from there. These CPUs only came in "FSB100 flavor", so you should have some room for overclocking, allowing you to see how far you can go.

I know the voltage question about the LX1664CD has already been resolved, but for what it's worth:
Don't trust the specs you see on 3rd party sites like digikey. They have errors all the time. AI is worse.
In this case, the stated max of 2.8V is clearly bad data, because Intel's spec dictates VRMs of this era should support up to 3.5V.

At the bottom of the 1st page of the "LX1664/LX1664A" datasheet, it shows a list of part number variants which includes the "CD" suffix as one of the options, so that datasheet is correct for the LX1664CD.
It appears that the "C" probably means Commercial temperature range (0-70C), and the "D" refers to the packaging type (16-pin SOIC).

So the LX1664CD is an "LX1664"(non-A) with the "CD" suffix to denote it's temperature range and packaging type.

shamino wrote on 2025-05-23, 08:33:

I know the voltage question about the LX1664CD has already been resolved, but for what it's worth: Don't trust the specs you see […]
Show full quote

I know the voltage question about the LX1664CD has already been resolved, but for what it's worth:
Don't trust the specs you see on 3rd party sites like digikey. They have errors all the time. AI is worse.
In this case, the stated max of 2.8V is clearly bad data, because Intel's spec dictates VRMs of this era should support up to 3.5V.

At the bottom of the 1st page of the "LX1664/LX1664A" datasheet, it shows a list of part number variants which includes the "CD" suffix as one of the options, so that datasheet is correct for the LX1664CD.
It appears that the "C" probably means Commercial temperature range (0-70C), and the "D" refers to the packaging type (16-pin SOIC).

So the LX1664CD is an "LX1664"(non-A) with the "CD" suffix to denote it's temperature range and packaging type.

As unreliable as AI can be, it did tell me about what the CD suffex meant. Thank you for clarifying some things.

Matt The Cat wrote on 2025-05-23, 03:05:

What do you suppose the highest I could go without replacing that component would be? Would a slot 1 850MHz Pentium III work without trouble?

Intel used these classifications for PentiumII/III VRM's:
VRM 8.2 1.30-2.05, 2.1-3.5 volts 16.1 amps (Pentium II =>PIII Katmai 500)
VRM 8.4 1.30-2.05 volts 22.8 amps (Coppermine)
VRM 8.5 1.050-1.825 volts 28.0 amps (Tualatin)
Assuming that your Biostar board's VRM section (thus not only the LX1664 chip) was properly updated you seem to be safe with the P3 850's current draw of 16.2 amps and it should still be in range (more or less) if your board's VRM was not updated from VRM 8.2.

PARKE wrote on 2025-05-23, 12:43:

Intel used these classifications for PentiumII/III VRM's: VRM 8.2 1.30-2.05, 2.1-3.5 volts 16.1 amps (Pentium II =>PIII Kat […]
Show full quote

Matt The Cat wrote on 2025-05-23, 03:05:

What do you suppose the highest I could go without replacing that component would be? Would a slot 1 850MHz Pentium III work without trouble?

Intel used these classifications for PentiumII/III VRM's:
VRM 8.2 1.30-2.05, 2.1-3.5 volts 16.1 amps (Pentium II =>PIII Katmai 500)
VRM 8.4 1.30-2.05 volts 22.8 amps (Coppermine)
VRM 8.5 1.050-1.825 volts 28.0 amps (Tualatin)
Assuming that your Biostar board's VRM section (thus not only the LX1664 chip) was properly updated you seem to be safe with the P3 850's current draw of 16.2 amps and it should still be in range (more or less) if your board's VRM was not updated from VRM 8.2.

I will have to consider this. Expect more to come in some number of months.

PARKE wrote on 2025-05-23, 12:43:

Intel used these classifications for PentiumII/III VRM's: VRM 8.2 1.30-2.05, 2.1-3.5 volts 16.1 amps (Pentium II =>PIII Kat […]
Show full quote

Matt The Cat wrote on 2025-05-23, 03:05:

What do you suppose the highest I could go without replacing that component would be? Would a slot 1 850MHz Pentium III work without trouble?

Intel used these classifications for PentiumII/III VRM's:
VRM 8.2 1.30-2.05, 2.1-3.5 volts 16.1 amps (Pentium II =>PIII Katmai 500)
VRM 8.4 1.30-2.05 volts 22.8 amps (Coppermine)
VRM 8.5 1.050-1.825 volts 28.0 amps (Tualatin)
Assuming that your Biostar board's VRM section (thus not only the LX1664 chip) was properly updated you seem to be safe with the P3 850's current draw of 16.2 amps and it should still be in range (more or less) if your board's VRM was not updated from VRM 8.2.

Would the 1.75 volts 1100MHz coppermine Celeron (SL5XU) have a usable amperage with the MSI slotket?

The 1100 Celeron draws the same amperage as the P3 1100 as far as I know and that falls in the 'probably not ok' category in the article I posted earlier.

PARKE wrote on 2025-05-23, 19:47:

The 1100 Celeron draws the same amperage as the P3 1100 as far as I know and that falls in the 'probably not ok' category in the article I posted earlier.

The attachment Copper.JPG is no longer available

Okay. I will have to save for an 850MHz Slot 1 P3. Do you know if there are ever faster Slot 1's available for sale?

PARKE wrote on 2025-05-23, 19:47:

The 1100 Celeron draws the same amperage as the P3 1100 as far as I know and that falls in the 'probably not ok' category in the article I posted earlier.

The attachment Copper.JPG is no longer available

Okay, I looked into the article.
I don't know how accurate it is, it would help if we knew the exact numbers, if this calculation method is true then the Celeron SL5XU 1100/128/100/1.75 has an 33w/1.75v~= 18.9A

So, that should be in the probably safe range eh?

Matt The Cat wrote on 2025-05-28, 18:55:

Okay, I looked into the article.
I don't know how accurate it is, it would help if we knew the exact numbers, if this calculation method is true then the Celeron SL5XU 1100/128/100/1.75 has an 33w/1.75v~= 18.9A
So, that should be in the probably safe range eh?

TDP is 33w, power is 39.6w - not the same thing.
The 22.6 amps for the Coppermine 1.1GHz is taken from the Intel datasheet. The Celeron datasheet does not mention current draw but the TDP of the 1100 Celeron is also 33w and we may assume that both the Pentium 1.1GHZ and the 1100 Celeron draw the same current.
Whether it is safe is up to you; your setup has a problem and you asked for info about a possible cause and that is what this is.

PARKE wrote on 2025-05-29, 00:29:

TDP is 33w, power is 39.6w - not the same thing. The 22.6 amps for the Coppermine 1.1GHz is taken from the Intel datasheet. The […]
Show full quote

Matt The Cat wrote on 2025-05-28, 18:55:

Okay, I looked into the article.
I don't know how accurate it is, it would help if we knew the exact numbers, if this calculation method is true then the Celeron SL5XU 1100/128/100/1.75 has an 33w/1.75v~= 18.9A
So, that should be in the probably safe range eh?

TDP is 33w, power is 39.6w - not the same thing.
The 22.6 amps for the Coppermine 1.1GHz is taken from the Intel datasheet. The Celeron datasheet does not mention current draw but the TDP of the 1100 Celeron is also 33w and we may assume that both the Pentium 1.1GHZ and the 1100 Celeron draw the same current.
Whether it is safe is up to you; your setup has a problem and you asked for info about a possible cause and that is what this is.

Thank you.