retropol wrote:

Hi,
question as in subject... do I need it for these processors.

what issues may occur (and what probability) if I will get rid of it.

Depends on how hard you want to run the CPU. And depends on how hot it runs. Back in 1995, I ran a fan on my DX2-66 with VLB VGA and VLB Controller. Just remember that heat are not good for electronics, so a well ventilated case will not be an issue.

I have a fan on my DX-33, just to be on the safe side.

Intel Overdrives come with heatsink permanently glued to the CPU - and that seems to be enough. So unless the case is a small, closed box with no room for airflow inside, that should be enough for DX2. At least for 66MHz, a Cyrix or AMD at 80MHz would run hotter than this.

In general these CPUs need a heatsink, will work for some time without one but probably not very long. With just the heatsink the temperature will reach high 60C, maybe even 70C, at this point silicon degradation is fast enough to consider it a problem - but still the CPU will last years of daily usage.

Many old AT cases were not exactly properly designed when it comes to cooling, most air was drawn in through floppy drives and all other small openings in the front. This alone, with all the cables inside blocking the air path as well, might not be enough. So for thoese original cases I'd recommend a fan on, or near the CPU. A slow 5V fan, doesn't even have to be attached, just blowing nearby. Simply put, any airflow over the heatsink will dramatically improve temperatures vs. no forced airflow.

DX2 66mhz is 5v CPU and most likely runs hotter than DX4 100mhz 3.45v.

All the computers i have seen from manufacture with a 486dx-66 install at least had a heat sink.
I would add a heat sink with fan on any cpu over 33mhz.
Take a heat gun to it and see how hot it gets ?
CPU’s and GPU’s run VERY HOT !
This is a major reason why they fail.

Let me repeat......

Every 486dx2-66 that I saw between 1993 and 1995, had a fan.

I got an fujitsu desktop dx2-66 just with a glued heatsink, no fan.
Also i could swear (which i won't do, as i could be wrong 😀) that my dx4-100 i got back in the day came without a fan.

Not really but to keep the processor "safe" it may be the best solution especially with the thin heatsinks that came with those cpus.

i'm literally working on a 486/66 right now, and it only has a heat-sink. it gets uncomfortably warm with the case open. With it closed, the fan in the PSU is enough to keep it in the "just fine" range.

that said, cooler is always better.

retropol wrote:

Hi,
question as in subject... do I need it for these processors.

what issues may occur (and what probability) if I will get rid of it.

I strongly recommend a heat sink for DX-40 and DX2-50.
You do not need a heat sink for DX-33 and anything slower.
I strongly recommand a heat sink and a fan for DX-50, DX2-66 and anything faster.

For old stuff even dont needing, better keeping cool.

Even an (Intel) 486/33 gets so hot when idling in DOS that one cannot touch it for long.
This indicates a ballpark temperature of somewhat over 60 C.
It definitely deserves a heat sink if you think conservative.

Other chips (mobo chipset! also GPU) should also get cooled if they get warm/hot.
If heatsinks get very hot they should get extra ventilation, too.
You don't want to have to replace your rare retro board too soon 😀

McBierle wrote:

I got an fujitsu desktop dx2-66 just with a glued heatsink, no fan.
Also i could swear (which i won't do, as i could be wrong 😀) that my dx4-100 i got back in the day came without a fan.

I bought one DX4 computer the other day that had even no heatsink 🤣

Looking at the CPU it self. The AMD 486 DX2 80 have "Heatsink and Fan required" written on top.
The AMD DX4-100 and 120 have it written as well.

EDIT:
Take a look at the AMD dx2-66 package here. It might not be written on all brands, yet this DX2-66 sure have it.
(Yet earlier AMD DX2-66 have nothing written on them. Intel I have no idea about.)
https://commons.wikimedia.org/wiki/File:AMD_A … X2_66_CPU_D.jpg

I guess they added it later, because some CPU's were used in poor ventilated machines, and they did
not want to be held reliable for machines cooking them self to death.

When I started studying computer technology in 1995, we were taught at school, that the DX2-66 was
able to run without any fan. Yet a heatsink was required. And you will be able to run it for a short time
without any heatsink and/or fan. Yet the teachers at school and the computer supporters and IT staff
at that school, all said that an SX25 or DX33 will run fine without anything. Yet they all said that you
need to run a DX2-66 with cooling.
They said that the DX2-66 were just too fast for what technology they are based on.

put a noctua NH-D15 on it

From the horse's mouth e.g. the Intel datasheet:

https://archive.org/details/bitsavers_intelda … tFeb92_14783795

So. You actually need 3 meter a second air flow inside the case, before it begins to be safe to run an Intel DX2-66 without heatsink? Below, you need heatsink or even heatsink and fan, or am I reading this correctly?

There is no mention of a fan but they mention fins on the sink. The key value in this sheet is max. 85 degrees celsius working temperature (which is enough to burn skin in a very short timespan). But I agree with the advise to put a fan on top because, Why not ? The question by OP was if it is needed.

If it's a 3.3V model (AMD, Cyrix etc.) you can get away without a heatsink. For the 5V Intel models if it's a regular ceramic cpu you need a fan inside the case or a heatsink; the overdrive intel cpus come with permanent heatsinks so those are just plug and play.

appiah4 wrote:

If it's a 3.3V model (AMD, Cyrix etc.) you can get away without a heatsink. For the 5V Intel models if it's a regular ceramic cpu you need a fan inside the case or a heatsink; the overdrive intel cpus come with permanent heatsinks so those are just plug and play.

Ohhh... That is right. Was there not something about them 5v AMD's frying them self to death?