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My Pentium I Build Thread

hunterjwizzard

hunterjwizzard

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Mar 20, 2020
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So I finally pulled the trigger on a socket 7 motherboard. While I wait for it to arrive, its time to go over and find all my parts. My plan is to use a PCI SCSI card, zuluSCSI, and CDrom drive.

To that end, I must first choose between these SCSI cards. Which one is better?

1746987038403.png

1746987054069.png

My gut tells me that first one, but only because it has more things on it.
 
I have a 2940 and really like it. The differences are slight.
The 2940 has a traditional 50 pin external connector; the 2906 has the 25 pin (Mac) external connector. Depending on what devices you plan on connecting, one might be easier to swap out unneeded devices from the chain.
The 2906 lacks the ROM support to boot. I don't know if you plan on having any bootable SCSI devices.
 
Motherboard arrived today:
1747071155770.png

M535 Motherboard
  • Award Bios id string 10/16/96-i430X-10031996C-00
    • 4-72 pin SIMM slots (8-128meg FPM/EDO 60ns DRAM)
      • 2-168pin DIMM slot (16Mx4, 8Mx8, 4Mx16 SDRAM pc66)
        • 4-32bit PCI Bus slots
          • 3-16bit ISA slots
          • 256k or 512k Onboard Pipelined Burst synchronous L2 cache
          • 160pin upgrade cache module
          • PS/2 Mouse Connector + USB connectors
          • Intel i430VX Pentium PCI chipset
          • 321pin ZIF socket 7 which supports these processors:INTEL Pentium 75~200MHz P54C, P55C MMXCYRIX/IBM 6x86MX, and AMD K5 CPUs
          • Supports 50/60/66/75 MHz external clock speeds
          • Multi-I/O chip supports:2 PCI Enhanced IDE Ports (Supports 4 Devices PIO 0-4)2 High Speed Serial Ports (16550 UART Compatible)1 Enhanced Parallel Port (SPP, EPP, ECP capable)1 Floppy Drive Port (Supports 2 Floppy Drives)
          • Manufactured by: 1437 Hsing Tech Enterprise Co., LTD.
          • Sold as: Ability, Amptron, Aristo, Eurone/Matsonic, Houston Tech, PCWare(Alton), Protac, PcChips, and Sybercom
Whilst shopping I completely missed that this machine does not take a CR2032 BIOS battery. Should I be concerned about whatever is providing power for the BIOS?
 
The battery is probably dead. I suspect that the Houston real time is a Dallas chip knockoff with all the same problems.
 
The seller sold me the board as "tested, working". but it was only $40.

Will that Houston cube come off if I pull on it, or is it soldered to the board?
 
Now I remembered how it felt good to see that chip first time in person for my new computer :)
 
hunterjwizzard said:
The seller sold me the board as "tested, working". but it was only $40.

Will that Houston cube come off if I pull on it, or is it soldered to the board?
Click to expand...
The Dallas chips were soldered on. Houston? Got no idea. If you don't see a socket, flip the motherboard over and see if the pins are soldered.
 
Well the slightly more important question is do I need to be worried about this thing popping off like a varta battery or is it safe to leave where it is?
 
The batteries inside those potted modules can still leak, but the potting resin usually keeps it contained inside the package since the battery pins never leave it and just go to the RTC chip.
 
Be aware that when the battery inside those Dallas-style modules dies, sometimes Award BIOS will see the "dead battery" bit in the CMOS and reset it back to the defaults on every single boot. If the defaults are such that it's impossible to boot, you might be stuck booting only from a floppy, for example. If it forces you into SETUP every time, sometimes you can "exit without saving" and attempt to boot.

I have a similar board, an MB-8500TUR, with the soldered chip. I was able to remove it using an iron and one of the "Engineer" solder suckers (with the silicone tip) and I am not good at it, at all.
 
As my wife says, I have the confidence of a mediocre white man, so I do believe I can remove the chip and solder in a socket of needbe. For now I'm gonna see if it works.
 
Next question: the board came with an Intel SY016 166mhz Pentium 1. I thought I had a 233mhz CPU somewhere around here but it turned out to be a celeron.

So, my question is: is there a better CPU I should pick up? And please note that "better" does not explicitly mean "the one with the most mhz".
 
I'd go Intel 166 over Celeron 233 assuming they are from the same family. But there is no real need to commit, build the system, then benchmark the two CPUs and keep the one that works best for you. Oh, and keep in mind you can probably clock that Intel CPU up to 200Mhz without any issues, just keep it cool. Since that board can do a 75Mhz FSB, I'd try a 2.5 multiplier with the 75Mhz bus, clocking the CPU at 188Mhz.

RE: The Dallas/Houston module. You absolutely will need to replace that battery at some point soon, so if I were you I'd definitely take the time to remove it and add a socket if it's not allready socketed. Then look up how to hack in a CR2032 into a Dallas RTC. It's very easy to do.

RE: SCSI - Stick w/ the one that has a ROM, the 2940. I have 4 of those cards, interestingly some revision drop the ROM support.

The board looks good. Did you see that the Retro web has the manual and some Windows drivers?

What else are you building into the machine?
 
hunterjwizzard said:
So, my question is: is there a better CPU I should pick up? And please note that "better" does not explicitly mean "the one with the most mhz".
Click to expand...

Just generically speaking the P55C (IE, the Pentium MMX) is a "nicer" CPU than the non-MMX one; they made a number of tweaks that give it a slightly higher IPC, it has twice the onboard cache, and it runs cooler. The main gotchya is you need a motherboard that supports split core/IO voltages. (SY016 is straight 3.3v, an MMX CPU is 2.8/3.3v.) Most socket 7 boards support split voltages, you just need to make sure you rejumper it correctly if you switch.

That said, realistically you're probably not going to see the difference between the two. On a good day a 166Mhz MMX might run some software as fast as 200Mhz non-MMX, but that's the kind of difference you usually need a stopwatch to percieve. If you're happy with just having a "pentium class" system the CPU you have is a perfectly middle of the road example.
 
Eudimorphodon said:
That said, realistically you're probably not going to see the difference between the two. On a good day a 166Mhz MMX might run some software as fast as 200Mhz non-MMX, but that's the kind of difference you usually need a stopwatch to percieve. If you're happy with just having a "pentium class" system the CPU you have is a perfectly middle of the road example.
Click to expand...
So here's my logic and tell me if I'm wrong: anything benefiting from higher speeds is probably going run on my Pentium III. Ero, my goal in this space is compatibility with older-generation stuff. So yeah, probably that 166 is right where I need to be.

Dumb question: do I need to slap a heat sink on here?
 
hunterjwizzard said:
Dumb question: do I need to slap a heat sink on here?
Click to expand...

Yeah, you should. The non-DX2 486es were the last Intel desktop CPUs that were even remotely safe to run without a heat sink, and even that comes with an asterisk. That heat sink should also have a fan unless your case has a fan ducted specifically to blow over the CPU. (That was pretty common on "brand name" systems, not so much on generic cases and homebuilds.)

It's my vague memory that heat sinks for Socket 370 (Celeron/Pentium III) are about the same size and *can* work on a socket 7 Pentium, but you'll have to reshape the clip a little because those later CPUs are a little thinner than a ceramic Pentium and you'll risk breaking the plastic tabs off the socket trying to get the PIII clip to engage.
 
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