View Full Version : 486 cooling

September 6th, 2009, 05:18 PM
Okay, it's confirmed, the gray in my hair is DEFINITELY brain cells leaking out.

I used to know this!

Do 486's need heat sinks and cooling fans? Or is it semi-optional?

BTW, it's a 486-DX2-66

September 6th, 2009, 05:32 PM
There are 486's here that have heatsinks on them, so not sure if it's necessary, but it couldn't hurt. At 66mhz I would feel safer having one than not.

September 6th, 2009, 05:36 PM
All of the 486s I have seen had heat sinks including the DX2-66s. I think the lower power 25MHz and DX2-50 didn't require heat sinks but I would install one anyway.

Fans seemed to be a rare option only placed in systems with very poor airflow.

Anonymous Coward
September 6th, 2009, 05:56 PM
Every 486 over 50MHz should use a heatsink, unless it's some kind of low power version.

September 6th, 2009, 06:15 PM
Yeah, I agree with that. Never saw see any 50Mhz units in my day but as soon as the DX-2 66MHz CPU's showed up they exhibited problems if they did not have at least a passive heat sink.

Ole Juul
September 6th, 2009, 07:15 PM
Here are some relevant examples (including newer hotter chips) from my recent experience:

Someone just gave me a Leading Edge Winpro 486. It has a TI 486SLC/E CPU which has no heat sink or fan. There is no space or provision for either, so I assume it has been running like this for years.

I have a 486DX4-S/100 which does not have a fan. I don't want to open it up right now to see if it has a heat sink, but it might not.

I have a Pentium 60 gold top which runs hot without a fan. However a little fan and no heat sink works. I'm not even sure that it wouldn't be OK without the fan - I just didn't like it so hot.

I have recently run a Pentium Pro without either heat sink or fan, but I deliberately underclocked it for the purpose.

I run a Pentium 133 with only a heat sink. It has a fan, but I disconnected it to make the machine more quiet. This machine runs 24/7 without any problem whatsoever. I left the fan in place just in case I needed it in hot weather, but the need has never arisen.

Looking at my "old board inventory", some 486s have a heatsink, some have heatsink and fan, and some have none. Years ago I used to run a 486DX2-66 without a fan. In those days I had other 486 machines too, and never did I have such fancy equipment as a CPU fan - IIRC, those were just starting to come out then.

Presumably it depends a lot on how you drive them, as witnessed by my running a PPro w/o either heatsink or fan. Some cooling technology should probably be filed under "artistic enhancement". :)

To me it looks like your answer is "semi optional" just like you said.

September 6th, 2009, 07:34 PM
My Compaq 486\DX2-50 had a passive heat sink ,factory installed.I later upgraded it to a Heat sink\Fan combo.It seemed to run a bit faster,the cooler it was kept.

September 6th, 2009, 07:37 PM
It depends--there were so many variations on the 486.

I would not expect an "L" (486SLC, 486SXL, 486SL) to require a heat sink--these are the low-power versions.

On the other hand, a 486DX-50 running at 50 MHz runs as hot as a two-dollar pistol and needs the heat sink.

A 5V DX2 probably would benefit from a heat sink; most 3.3v 486 chips may not, with the possible exception of a DX4 run at top speed.

I used heat sinks (and CPU fans) on my DX4, Cyrix and Am5x86 motherboards.

September 15th, 2009, 04:13 PM
My friend has a Packard Bell with a SX in it that has no heatsync.

I was running a DX2 without a heatsync, and it got super hot, so I ordered a heatsync/fan.

September 15th, 2009, 05:19 PM
I seem to remember my 486DX-66 as having a passive heatsink.


September 15th, 2009, 05:33 PM
IIRC different manufacturers did different things on this count. Some had heat sinks only, some had both heat sinks and fans and some had neither. Very few I encountered had thermal grease.

Bottom line I think would be to say, it may not be required, but will never hurt and can only help. At the very least I would put a heat sink on any that I had.

Hope that helps.