i'd certainly put heatsinks on the pentiums and probably a cooler as well, the p120 of mine gets very hot and my p233mmx just freezed when the cooler died. CPU survived though, sturdy things 😀

Not sure about 40MHz, but 66MHz+ 486s always had heatsink and fan. Slower Pentiums may have only a heatsink and no fan if the power supply fan helps it. 33MHz and slower 486s had neither fan nor heatsink.

My 486 DX2 50 MHz system came with the CPU completely bare. There was heat there alright, but it worked fine for years.

I guess 486DX2 series onwards are preferred to have heatsinks on them. Most of the "classic" heatsinks have plastic brackets to hold the sink to the processor.

Thanks very much for your advice guys! 😁

I need to go look for some heatsinks which will properly "clip on" to my '66mhz 486' CPU, and both my Pentium I CPUs!

Edit:

Pardon me for being such a twit, but I found this item on ebay:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewIt … em=180198791014

and wondered if it would be suitable for either an Intel 486DX CPU, and/or an old Intel Pentium I CPU (such as a P133 or P200MMX)

It's described as a "PGA370 - SOCKET 7 HEATSINK & FAN"

Thanks for helping out a rather stupid person. I found building my new XP box quite easy, but this retro stuff is where the real hard work is! 🤣

That will cool a Pentium just fine.

For a 486 it is overkill (lose the fan).
If you want an indication of how big a heatsink is needed, have a look at the Intel Overdrive CPU.

http://cpu-museum.de/?m=Intel&f=Overdrive+CPUs

You can use thermalglue to glue a simple heatsink on a 486 (or any other cpu for that matter) instead of the plastic clips. That way you don't have to look for a heatsink of that age.

I like to epoxy the heatsink to the CPU, this avoids the usual hassle with the mounting clamps and thermal grease, while offering very good heat transfer and allowing for quick CPU swaps.

Of course this method is not recommended if you want to resell the CPU or look at the surface print ever again, because once the epoxy is set, there is no way to get the heatsink off without destroying the CPU.

Usually I try to find an aluminium heatsink which doesn't exceed the measurements of the CPU at the baseplate, but with the fins as high as possible.

If you have a high quality heatsink and the air flow in the case is good enough, a CPU fan is not necessary, even on faster processors (my K6-3+ works fine at 500 MHz without a CPU fan).

Pentium heatsinks are usually 50mm square - both heatsink and fan (and CPU, for that matter). I wanted to replace the fan on mine, but I can't find any 50-70 or 50-80mm fan adapters. Any heatsink bigger than 50mm for my motherboard would hit a nearby capacitor. A P166 may not need a fan, but I don't want to take the chance.

Bahh.. It'll get flaky before it cooks. Unless it scorches your finger, I wouldn't worry too much about running a P166 fanless as long as the heatsink isn't puny and there is some air movement in the case.

CPUs from those yonder years are really rather low on the heat output. According to Sandpile.org, it's only a ~15W CPU at max.

As always guys, your collective wisdom is invaluable. Thanks very much!! 😁

The fastest CPU I've ever seen without a fan was a 733MHz Intel P3.

what about dual 700mhz PIII celerons oc'd to 933mhz? That was a system I used ages ago and it never had heat issues, even when rendering in Max and AfterFX.

Yeah, i had a dual 866 p3 system, they only had heat sinks, though the case seemed chock full with of scsi drives, full length cards, and oem-ducting around the processors. Always felt the air flow must have been awful but never any overheating trouble An ibm workstation iirc.

Why does the yes/no heatsink issue always remain guessing in this mathematical IT area?

There must be a limit to the amount of Watt a heatsink can dissipate before the heatsink required becomes too big or the material used simply can not conduct the heat fast enough.

I found this http://www.novelconceptsinc.com/calculators-f … -resistance.cgi calculator, but those variables are only part of the answer.

Where on the web can be found the enlightened statement of an engineer showing the maximum amount of Watt that can be dissipated using a copper heatsink still small enough to fit inside a normal sized case?

There are passive Radeon HD4850 cards out there and those draw about 100W when peaked. That is way beyond what any retro hardware would draw.

My Voodoo3 2000 PCI card gives off the most amount of heat I've ever felt from any piece of computer hardware. So much heat in fact, that I've removed it from the machine it was in - I don't want it cooking the rest of my components. Can these cards be overclocked? If they can, that might explain why it's belching out so much heat.

We shouldn't let the human skin threshold for heat influence our decisions in machine part world.

I get the feeling all this heat is felt to be scary, but only because when people touch it it hurts.

If the cooling isn't modified and if you touch it and don't have an instant blister it is fine.

the voodoo3 (whatever bus/model) produces LOTS of heat. It will not break though, or break other components. I and many friends had it when it was new, we never even knew it was hot, and nothing ever happened. and we had countless gaming sessions as kids btw 🤣
Nowdays on all my voodoo3 cards, I add a small 40x40x10mm 4000-4500rpm fan on the heatsink, quiet and keeps the voodoo3 cool at all times 😀

Yeah there is no reason to need a fan in a retro system IMO. Socket A/370 heatsinks are compatible with Socket 7 (as long as the socket isn't surrounded by caps) and they also are designed for 30-80W CPUs so they often more than adequately passively cool a K5 and older.

The only fan you really need is the PSU fan. I am really against fans unless they are necessary. Fans usually fail eventually and they are noisy.

I think the only risk is instability because these systems are going to be in use by you when they're on and you're going to notice if its overheating and freezing up. With almost any Socket 370/A heatsink, I doubt a Pentium could hit even its max rated temp running 100%, let alone cook.