One thing you could try is chipset (northbridge) heatsinks. They are similar in size to 486 CPUs and dissipate similar amounts of heat (if not a bit more). You can get them with adhesive thermal tape, which should suffice.

That said, looking for those I came across perfectly reasonably priced 486 ones:
https://www.ebay.com/itm/Ever-Cool-EC-486-40m … VYAAOSwMNxXUIfs

USD 7 for the HSF combo. For me on the other side of the pond shipping would be steep, but if you're in USA as your profile suggests that shouldn't be a problem.

I am from denmark, and I do not think that shipping is that big an issue in this case.
I had stuff shipped from Germany, more exact an Amiga-to-vga adaptor, were shipping fee was higher.
When I think about it, I might have bought two of those coolers from the same seller at one point.

I managed to create my own Socket 3 heatsinks, or, in fact, heatsinks attached directly to the CPU (because that's the way it usually worked), you just need a piece of plastic and cut it in a way that is shown on the image, so it will clip the heatsink to the CPU. Put some cheap thermal grease between heatsink and the CPU, this adds some stickness and prevents the heatsink from moving. Later I printed such clips on 3D printer, using ABS plastic. I used cheap heatsinks from electronic store.

Anyway, that $6.49 heatsink looks nice.

dionb wrote:

One thing you could try is chipset (northbridge) heatsinks. They are similar in size to 486 CPUs and dissipate similar amounts o […]
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One thing you could try is chipset (northbridge) heatsinks. They are similar in size to 486 CPUs and dissipate similar amounts of heat (if not a bit more). You can get them with adhesive thermal tape, which should suffice.

That said, looking for those I came across perfectly reasonably priced 486 ones:
https://www.ebay.com/itm/Ever-Cool-EC-486-40m … VYAAOSwMNxXUIfs

USD 7 for the HSF combo. For me on the other side of the pond shipping would be steep, but if you're in USA as your profile suggests that shouldn't be a problem.

Meh, shipping for a single one is still $5.49. As an eBay seller, I know that those would not cost any more than about $2.00 to ship.

Guessing they are paying full price for shipping (not purchasing shipping through eBay) and also not offering first class shipping.

adalbert wrote:

I managed to create my own Socket 3 heatsinks, or, in fact, heatsinks attached directly to the CPU (because that's the way it usually worked), you just need a piece of plastic and cut it in a way that is shown on the image, so it will clip the heatsink to the CPU. Put some cheap thermal grease between heatsink and the CPU, this adds some stickness and prevents the heatsink from moving. Later I printed such clips on 3D printer, using ABS plastic. I used cheap heatsinks from electronic store.

Anyway, that $6.49 heatsink looks nice.

Ooohh, nice. Now if I only had a 3d printer.

What speed of 486 are you running and how warm/hot does the heatsink get under full load?

I made a "prototype" using some leftover plastic pieces, a knife and a file (white clip on the left photo). The tip of the clip needs to be made pretty accurately, but it's not too hard to make. A piece of ABS or polystyrene (DVD case) should be good to try. The plastic needs to have some elasticity. But running the strings under the CPU should also be fine.

cyclone3d wrote:

What speed of 486 are you running and how warm/hot does the heatsink get under full load?

The smaller heatsink is fine for Intel 486 DX2/66 running on stock settings, it's warm but not too hot. Stock heatsinks for this model were made in similar size: cdn.cpu-world.com/CPUs/80486/L_Intel-A8 ... tsink).jpg

Intel or AMD 486 DX4 100MHz are too hot for that small heatsink (too hot to touch after a while), the bigger one also gets pretty warm so installing a fan is advised. But they wouldn't probably get damaged while using the larger heatsink, even without a fan.

I also tried overclocking Intel and AMD 486 DX4 to 120MHz and they were working nicely with the larger heatsink and a fan installed (i even slowed down the fan with a resistor, because it was noisy).

Ok, great. I ended up ordering 5x 40x40x11mm heatsinks from China for $2.79 total shipped.

https://www.ebay.com/itm/5pcs-40x40x11mm-LED- … es/302300250759

At that price it is not even worth me messing with modifying larger ones to fit.

I'll probably just have an 80mm fan mounted somewhere to blow in the direction of the heatsink. I really despise those little junky fans that came with the 486 heatsinks as they always seemed to die pretty quickly.

The CPUs I have are both AMD. A DX2-80 and a DX4-100.

I've also got a Kingston 5x86 133 chip, but I don't know if it works. Arrived with bent legs on the CPU package itself as well as there being corrosion in between a lot of the legs. I got a refund. I may try to straiten out the legs and clean it off but not sure I want to chance frying a board with it.