Difference between Pentium 2 and Pentium 3

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Joined: Apr 22 2004
Posts: 379

Just a stupid question - what's the difference between these two chips?

I have a PC with a Slot 1 motherboard and a Pentium 2-450mhz processor.
I also have a Pentium 3-500mhz processor that won't fit due to the proximity of the capacitors to the CPU slot. The pins holding the heat sink/fan on the P3-500 chip come in contact with the capacitors.

What am I missing out on (if anything) by not trying to add a Pentium 3 processor to the board?

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Joined: Sep 23 2005
Posts: 316
well...

1st of all your most likely "missing out" on a board that supports the P3's architecure for 1.....

Eudimorphodon's picture
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Re: Difference between Pentium 2 and Pentium 3

bfutrel wrote:

What am I missing out on (if anything) by not trying to add a Pentium 3 processor to the board?

Not a whole lot. The Pentium III heralded the debut of the "SSE" multimedia instruction extensions, which basically allow the floating-point hardware of the CPU to be exploited more easily for certain more "generalized" computational tasks. Other then that PIII is essentially identical to the PII, and the lack of SSE has very few real-world implications. (Most programs which support the use the optimized media instruction sets like SSE/SSE2/SSE3 or 3DNow! check for the presence/lack of of them and fall back to using good old Pentium/PentiumII MMX+387 floating point libraries if it's missing.)

It is odd you're having a physical interference issue. By any chance does your PIII say "500E" on it anywhere? There are two kinds of PIIIs, the "Katmai" models with external L2 cache chips (like the Pentium II), and "Coppermine" (E) models with on-die cache. The heatsink/fan arrangement is *slightly* different on the two models, with the Katmai's of course being identical to PIIs. If you have a Coppermine CPU that could explain the fit problem. (The board manufacturer must of *slavishly* followed the physical dimensions of the original PII package when designing the board.)

--Peace

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Joined: Apr 22 2004
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I'll have to look at the processor

It's at home and I'm at work right now.

As far as I know it has the external cache chips on it. The motherboard may have not been designed for a P3 chip, but it has a 440BX chipset on it so it can run one if I can get it to fit. It originally came with a P2-400.

The PC is a Micron Millenia XI. While the case is almost exactly like the Dell Dimension mid-towers made at the time, the front is slightly different. At least the motherboard is 'generic'.

Coming down from a Sempron 2200, it's not as slow as I thought it would be. At least after adding the ATA-133 raid card - ATA-33 crawls. Smile

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uh...

I thought P II's were not socketed, but rather in "Slots"

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They came in both slot and so

They came in both slot and sockety flavours.

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Eudimorphodon's picture
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Or...

To clarify, Pentium IIIs came in both slot and socket flavors. All "real" Pentium IIs are slot packaged.

("Dixon" Mobile Pentium IIs came in special laptop-size socket form, but they're also arguably not "real" Pentium IIs. They're more like Mendocino Celerons with 256k instead of 128k onboard cache.)

--Peace

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And it's worth mentioning tha

And it's worth mentioning that the 66MHz bus Celerons were fantastic overclockers. Not like an extra 100MHz will get you very far these days, though.

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Re: Difference between Pentium 2 and Pentium 3

Eudimorphodon wrote:

If you have a Coppermine CPU that could explain the fit problem. (The board manufacturer must of *slavishly* followed the physical dimensions of the original PII package when designing the board.)
--Peace

I found a way to put a PIII processor in the board. If you find one from a Dell from that era, it has a heat sink with mounts that don't project through the plastic shell of the package.

The only problem would be cooling - the processors from Dell at the time did not have fans on them. They had a cowl mounted over the exhaust fan that allowed air to pass through the fins on the heat sink.

I got a shell of a Dell Dimension for $15 to replace the power supply in my Dimension XPS T550 (power glitch took it out). While I was at it I swapped the P3-550 from the intact one with the P3-450 from the shell. It's only used for iTunes serving, so being slower doesn't matter too much.

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So far so good

It's now running a P3-550. Since there is no fan on the heatsink, I had to make a custom cowl to direct the air over the heatsink and out of the case. It's running cooler than the P2-450 it replaced.

CPUID recognizes it as a P3-550. BIOS recognizes it as a Pentium Pro 500. (????)