VOGONS


First post, by squareguy

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Well I like messing with various CPU's, kind of a hobby in and of itself. Anyways would like to hear some feedback on this idea.

I crunched some numbers and here is what I came up with. I do not have this CPU in my possession yet, just thinking out loud but it seems interesting to me.

Intel Pentium III 533EB, 4x133, 256k Cache, 1.65V, 14W TDP. Undesirable CPU that is cheap on ebay,

OEM high quality BX boards are cheap or free and still 'findable' locally, here at least. Gateway, Dell, etc. Stable but no real features. Do not 'need' features since 533EB is locked. These boards will not post with a 133FSB CPU installed. I doubt it has anything to do with CPU ID and simply a matter of the presence of BSEL1. BSEL0 defines 66/100FSB and BSEL0 in combination with BSEL1 defines 100/133FSB, for lack of better words.

Modify 533EB PCB by replacing 4 resistors with 4 shunts. That will set 66FSB and should allow it to function @ 266 (4x66) on any board including finicky OEM boards. This is easy enough.

OK, so why?

Running @ 266 the 533EB roughly will have a TDP of 7-Watts. Can you say completely silent passively cooled?

OK, so what?

Well, it just so happens that 266-MHz is a magic number of sorts. I'll explain.

Using Throttle http://www.oldskool.org/pc/throttle/DOS/ which I have had a lot of luck with on BX boards we get hardware speed reductions ranging from none to 87.5% in 12.5% increments. OK, so look at how these numbers lineup.

Percentages of full speed, rounded off to nearest whole number +-1 for ease of comparison.

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So, do you think this is worth pursuing?

I will probably grab a 533EB soon.

Gateway 2000 Case and 200-Watt PSU
Intel SE440BX-2 Motherboard
Intel Pentium III 450 CPU
Micron 384MB SDRAM (3x128)
Compaq Voodoo3 3500 TV Graphics Card
Turtle Beach Santa Cruz Sound Card
Western Digital 7200-RPM, 8MB-Cache, 160GB Hard Drive
Windows 98 SE

Reply 1 of 9, by squareguy

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I forgot to mention. These boards need to be a new enough revision to support the Coppermine CPU's. I have several Intel SE440BX-2's that do and I have several OEM boards that I can test as well.

A Deschutes 266 would be a pretty good substitution.

SL2K9, SL2QE, SL2W7, SL33D with a TDP of about 17-Watts.

Gateway 2000 Case and 200-Watt PSU
Intel SE440BX-2 Motherboard
Intel Pentium III 450 CPU
Micron 384MB SDRAM (3x128)
Compaq Voodoo3 3500 TV Graphics Card
Turtle Beach Santa Cruz Sound Card
Western Digital 7200-RPM, 8MB-Cache, 160GB Hard Drive
Windows 98 SE

Reply 2 of 9, by squareguy

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I am going to try to test the theory with a Pentium II 333 @ 266 and run speed tests. Might take a few days. Out of all the tests done before what are 'we' considering the most desirable now.

3DBENCH
PCPBench
Speedsys
Doom
Quake @ what res? 320x200, 320x240?

Gateway 2000 Case and 200-Watt PSU
Intel SE440BX-2 Motherboard
Intel Pentium III 450 CPU
Micron 384MB SDRAM (3x128)
Compaq Voodoo3 3500 TV Graphics Card
Turtle Beach Santa Cruz Sound Card
Western Digital 7200-RPM, 8MB-Cache, 160GB Hard Drive
Windows 98 SE

Reply 3 of 9, by gerwin

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squareguy wrote:

Modify 533EB PCB by replacing 4 resistors with 4 shunts. That will set 66FSB and should allow it to function @ 266 (4x66) on any board including finicky OEM boards. This is easy enough.

Watch out for what can happen!
My tinkering with an Intel SR440BX motherboard
... OK, so nothing really happens, it works as intended. 😀
You can even downvolt to 1,3Volt or something, which substantially decreases Wattage and tends to work fine in this case.
The Socket 370 Version of the 533EB a bit more mod-friendly in combination with a slotket.

Last edited by gerwin on 2018-11-11, 19:18. Edited 1 time in total.

--> ISA Soundcard Overview // Doom MBF 2.04 // SetMul

Reply 4 of 9, by The Serpent Rider

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A Deschutes 266 would be a pretty good substitution.

Hardly, those are more power hungry and limited to Slot 1.

So, do you think this is worth pursuing?

It should be considered as an alternative to the VIA C3 series, though latter could go slower or even faster.

Quake @ what res? 320x200, 320x240?

Default is 320x200, 2 HUD bars (health, ammo + weapons, keys)

Last edited by The Serpent Rider on 2018-11-11, 21:27. Edited 2 times in total.

Get up, come on get down with the sickness
Open up your hate, and let it flow into me

Reply 5 of 9, by squareguy

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Another side note.

Just in case you didn't know, SE440BX-2's and their OEM counterparts do in fact have a jumper setting to allow you to configure the CPU multiplier in BIOS (softmenu) if the CPU is unlocked. Once set you power off machine, return jumper to normal operation, then configure/reconfigure standard BIOS settings then you are good to go. I have a Gateway board that actually allows choosing 233-533 with a 333 installed, of course there is no option for FSB. That has to be handled with B21 trick or modding BSEL on CPU PCB.

Gateway 2000 Case and 200-Watt PSU
Intel SE440BX-2 Motherboard
Intel Pentium III 450 CPU
Micron 384MB SDRAM (3x128)
Compaq Voodoo3 3500 TV Graphics Card
Turtle Beach Santa Cruz Sound Card
Western Digital 7200-RPM, 8MB-Cache, 160GB Hard Drive
Windows 98 SE

Reply 7 of 9, by gerwin

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squareguy wrote:

Using Throttle http://www.oldskool.org/pc/throttle/DOS/ which I have had a lot of luck with on BX boards we get hardware speed reductions ranging from none to 87.5% in 12.5% increments. OK, so look at how these numbers lineup.

Throttle is a nice option on the side. But there are plenty games that are not running smooth with it. Slower but not smooth. This is not just me. But I cannot say now what the percentage is or anything. Contrary to throttle, actual downclocking and cache disabling works pretty reliable.

--> ISA Soundcard Overview // Doom MBF 2.04 // SetMul

Reply 8 of 9, by The Serpent Rider

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Contrary to throttle, actual downclocking and cache disabling works pretty reliable.

Nothing to see here, folks, back to VIA C3 discussion 🤣

Get up, come on get down with the sickness
Open up your hate, and let it flow into me

Reply 9 of 9, by squareguy

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Thanks for replies.

Gerwin,

I thought about undervolting but I'm really glad you have some info!

my limited amount of time with throttle suggests to me that it is much more useful on a slower than a faster CPU. Talking about smoothness, I may be wrong.

Serpent,

I am only keeping my SE440BX-2's and OEM boards. I am selling all my others. I am also tired of trying to track down an Ezra CPU. It's like a unicorn or something. At least with my searching on ebay. I can never say for sure if that's what it is before purchasing based on the package, voltage, speed, etc. Not gonna but a bunch and test.

Gateway 2000 Case and 200-Watt PSU
Intel SE440BX-2 Motherboard
Intel Pentium III 450 CPU
Micron 384MB SDRAM (3x128)
Compaq Voodoo3 3500 TV Graphics Card
Turtle Beach Santa Cruz Sound Card
Western Digital 7200-RPM, 8MB-Cache, 160GB Hard Drive
Windows 98 SE