I am sorry to say this but they are not intended for 486s, they seem north/south bridge cpu cooler sinks with retention metal clips.
They look like some intel chipset use them, i have one, take good notice to the retention ends that are curved to fit the round clamps that are soldered onto the mainboard itself.
These z clamps would have to be flat at the outer edges to grab those socket ends.
I made some from a 1mm thick paperclips and some hand tools to flatten them and reshape/ curve them to fit the socket, this works fine, no pressure needed only to keep the heatsink on its place.

Check

And for northbridge:
http://www.techwarelabs.com/reviews/motherboa … /epox/ep_4g4a+/

JaNoZ, do you have such a chipset cooler and clip to test on your socket 3 486? If you haven't tested it, I wonder if it still may work? I have sent the seller a message requesting dimensions and the spec sheet.

yep, those on the eBay auction do look like chipset coolers... my old intel atom and the older celeron mITX boards used similar hearsinks, that retention clip needs those 2 anchors on the mobo to fit

Hmmm, I'm not so sure - the eBay ones look a lot like passive sinks I remember seeing on some early Pentiums. They were the fin type too with some sort of wire retention system. I'd be inclined to think the same type of cooling device was used for multiple purposes and those used for chipsets have simply endured longer.

I picked up an early Pentium off eBay about 2 years ago in part because it was pictured with such a sink. Unfortunately the seller substituted another P2 style bar heat sink. I think the seller gave me a partial refund after I queried him.

EDIT: too far back in eBay archive history to still have a picture. It was a P-233 w/ sink for under $5 postage included - so I don't think I insisted or received any kind of refund 🤣.

I have a bunch of dead motherboards in a box. Haev to see, if there's anything in there that looks like the heatsink above.

With my local fry's electronics they still have 486 CPU coolers, 50cents each. Might grab four sometime, would love to see the face of the 20 something thinning at the checkout counter "what's he gonna do with these?" 🤣

Why not grab all of them at 50 cents each...?

Hi Guys,

Made some comparisations for a 486 board and the Norhtbridge heatsink with the clamp thingy's
Also you can make your own clamp with thick paperclip and some tools, like i did some ages ago with a smaller paperclip (although a thicker clip is stronger)

feipoa wrote:

JaNoZ, do you have such a chipset cooler and clip to test on your socket 3 486? If you haven't tested it, I wonder if it still may work? I have sent the seller a message requesting dimensions and the spec sheet.

I'm very certain the Ebay auction is for 486/Early Pentiums and not modern chipsets. They look exactly like the ones that are installed in my newly acquired IBM Servers (see other thread). Could be that these are old OEM IBM heatsinks.

wow Janoz; a paper clip and some pliers. looks like a really good job too 😀

that seller is a pain in the butt anyway, his comms are terrible and he thought he would sell 5 for 30 pound.

He also added a number of countries to postage but not mine 😜

I'm having issues with that seller as well. I'm trying to get him to measure the dimensions of the retaining clip.

Also, instead of my requested 15 pounds for 5, he put 30 pounds for 5 - a 100% mark-up.

Janoz, That looks like a M915 you have there. Does it work? Why does it hae two UM8886AF chips? I think the one with the sticker on it is really UM8881F.

vetz wrote:

I'm very certain the Ebay auction is for 486/Early Pentiums and not modern chipsets..

I agree...

I stumbled upon this webpage and was just amazed, i thought i had a collection but this guy most be a big spender.
And has a sh!t load of cpus to test.
Is he already at vogons.?
I first thought it was a gold scrap seller, and was already checking my wallet to get some cpu's i could use. 😊
Maybe he has a box or source for z clamps.
http://www.rarecpus.com/massquantities.html

wow what a mad hoarder 😀

doesn't look like anything is for sale but what a cool collection....

his last update was 2010 ...but it's worth a try!

I was informed by the seller of the z-clip that the end-to-end length is 6.6 cm. I measured my socket 3 tabs, they are 6.1 cm end-to-end.

I am not pleased with this sellers price for 5 units. Anyone in the UK want to buy in bulk and fan-out to the rest of us?

Yes it is a m915 and is working perfectly with a am5x86 at 150mhz.
The 2nd 8886af is actually a 8881 of course with a sticker on it, and is placed perfectly between cpu and cache to ram. 😀

Janoz, how much cache do you have installed and what cache timings are you using for 50 MHz operation? Have you tried 1024K in this motherboard?

I havent used the board for over 15 years now,a year ago i ditched the heavy server style at case it came in for pleasing my wife and quickly removed the board and the 250w enermax psu.

If i recall correctly i was using all tightest timings but it was only capable with this set of 2x8mb micron ram.
Any more or different type or brand ram would not work at that timings.
There is 16mb in total and 8x32k umc 15ns cache that makes only 256kb, i do have some 8x64k i could give a try but i do not have 128k cache ic's.
The board ran ok with quake and team Fortress for quake, also win95c.

I will give it a try soon and show some screeny's

Janoz, I am very interested if you can run this board with 1024K, the tightest cache/memory timings, and 2x64MB FPM memory. If it is not too much to ask, a test with an AMD X5-133 and AMD X5-160 would be appreciated. L2 set to WB mode. I have a dead one of these boards, but I am using it as part of a reverse engineering process to add 1024K to my MB8433-UUD board. Please use HIMEM and Memtest 4.0, test #6 as a means to gauge stability. You can select just test #6 from within Memtest to speed up the process. Press 'C' when memtest starts to bring up the configuration menu.

The M915 uses a 22-ohm resistor pack between the cache addresses and the TAG addresses. The MB8433 has no resistor between these addresses. The DTK-PKM-0033S uses a 72F244 buffer between each, while the HOT-433 uses some unknown UM8002 chip. While I can route the MB8433-UUD to use 1024K cache with 0-ohms between cache and TAG addresses very easily, I cannot use 2-1-1-1 cache timings with an X5-133. I need to reduce the speed to 3-1-1-1 with 2x64 MB of RAM, however I can use 2-1-1-1 with 512K, single-banked, and 2x64MB of RAM. Naturally, I want to use the fastest timings. The DTK-PKM board, though based on the SiS496/497 chipset, can use 1024K, 2x64MB, X5-160, all on the fastest timings. That design uses the buffers between each cache address and the TAG address. Basically, if your M915, which is based on the UMC chipset like the MB8433, can get away with just a 22 ohm resistor pack between the cache and TAG address and works on the fastest settings w/1024K and 2x64 MB RAM, then that is the simpler design I will use on my modified MB8433.

Thanks a lot!

I want to test the board no problem, and i have 2x64mb several sets more of them actually samsung chipped.
But i do not have any 128k srams, i wanted to buy some at ebay last week but they turned out to be some 64K caches which i already have.