Comment by soylentcola | Hacker News Reader

Comment by soylentcola | Hacker News Reader

The talk of older processors not needing heatsinks/fans reminded me of my first (and thankfully last) lesson on this matter back around 2001-ish.

In the past I'd assembled several PCs and my less-than-rigorous setup process typically involved slotting the CPU, RAM, and other cards, then plugging it into a monitor and powering up to run through a quick POST just to make sure nothing was misaligned or improperly seated. Then I'd power off, put down some thermal paste, mount the heatsink/fan, and connect any remaining cables for drives, etc.

Well, in the past, this was fine. Sure, I wouldn't want to run things without at least the crappy little Intel or AMD CPU fan but 5 or 10 seconds was no big deal. But this time I was building for a friend who had me order one of those fancy new 1GHz Athlon chips. I was psyched as well because the small markup I'd added for my time helped me afford my own fancy 1GHz CPU and new motherboard for my own PC.

So I followed my usual procedure and slotted everything for the initial POST (nothing worse than getting everything connected in one of those old PC cases with IDE cables and wires everywhere just to have to unhook it all because something wasn't seated properly) and powered on.

Blink.

Nothing.

Hmm...Did I not get the CPU seated properly? Let's pop it out and reseat it. OWW! Burned the crap out of my finger and got a blister!

Uh oh. It sorta smells like the magic smoke even though I don't see any. Well, eventually I realized what had happened and learned that even a few seconds without a heatsink/fan had been enough to fry that brand new 1GHz Athlon.

Thankfully I had the one I'd ordered for myself and I was able to finish the build that my friend had paid for. But it was a rather expensive (for me at the time at least) lesson in the need for proper cooling on these modern CPUs.

You were lucky that's all that happened. Athlon's ran notoriously hot to the point that they would literally catch fire after a few seconds if no cooling was applied.

I scorched at least two Athlon's back in the day. Those buggers ran crazy hot.

You're just not looking at Intel processors that are old enough :)

80286 needed no heat sinks, even 20-MHz models.

80386 used to do well without radiators, too, or with entirely passive cooling, even the faster DX variants.

Frankly, I don't remember low-power i486 (e.g. 40-MHz versions) to have heat sinks, too. You definitely wanted a heat sink, though usually a passive one, on a DX2 (66 MHz) or DX4 (100 MHz).

My 486/DX 33MHz didn't have a heat sink, and while it ran hot, it wasn't too hot to touch.

The column "The Hard Edge" in Computer Shopper magazine (Bill O'Brien and Alice Hill) teased Intel's heat output on the new "Pentium" chip by saying they'd get a tiny frying pan made to fry an egg on it. :-) (can't find the original article, but it's referred to in this 1997 article https://www.highbeam.com/doc/1G1-19334858.html )

Before then, I don't remember my IBM 386/75 or 486 needing fans ... but the 486DX2/50 had problems with RF emissions from the corners of motherboard traces (IIRC) so they left external clock speed lower for many moons ...

IIRC, my old 486SX at 25 MHz didn't use a heatsink.

I bought a desktop computer in ~2004 and as usual I just pick the best hardware I could afford back then.

I still feel cheated by Intel, because working on that crap was like working on an airplane turbine. The noise and the heat was impossible to tolerate to the point that some companies started to sell solutions for this thing back then, some even using water. I ended up buying a huge blue dissipator.

Intel used me to test their new Hyperthreading technology, the processor was called Prescott, a.k.a "Pres-Hot".

https://en.wikipedia.org/wiki/Pentium_4#Prescott

I remember those damn Prescott cores. I had one on a custom build I did for myself back in High School.

After setting that bad boy up, it ran so hot that my room was about 5 degrees hotter than the rest of the house. I finally started putting it to sleep for most of the day just to keep the heat down.

I actually applied an absolutely-final overkill solution to the noise&heat problem on my desktop - I run a full liquid cooling setup with a giant heatsink with three fans on it mounted fully outside the case. It's mounted on my desk. The noise is unnoticeable and cpu temp is 27C at idle, 60C at full burn.

I wonder if some processors like prescot actually need to run hot

I wonder if some processors like prescot actually need to run hot

Generally speaking, no. Some are more tolerant of high temperatures, but that's it. And higher temperatures in general will degrade the processor over time.

I wonder how much of that reputation is based on absolute power consumption, and how much comes from the relative huge jump from preceding Pentium III's. Checking from ARK, when looking at mainstream models the first gen P4's consumed 60ish watts which grew to 85ish watts in the end (precott). That sounds pretty much in line with all the CPUs that followed. But it was radical rise from the <30ish watts that PIIIs consumed. Of course the top of the line P4s were even more hotter (in the 115-130 watt range) but that is actually also still in line with more recent CPUs. It's just less visible as Intel in their great wisdom has limited the top models to server Xeons and thus out of the hands of consumers.

At the time water-based heatpipes weren't used for coolers, which made all coolers much, much less efficient. Today practically every CPU cooler uses 2-8 heatpipes and that's what makes all the difference. (Well that and not using top-blowers anymore).

>That sounds pretty much in line with all the CPUs that followed.

Because the Intel CPUs that followed actually had power saving features, previously found only on mobile versions.

Those P4 would just run hot all the time, not pleasant being in computer lab with two dozens of them + CRTs and AC that couldn't keep up.

Great story. When I upgraded from a 486DX2/50 to a Pentium 133, I thought for sure there was something wrong with the voltage regulator on the motherboard because the chip was throwing off so much heat. Spent hours on the phone with Tyan technical support (which was great) and a multimeter and even swapped out the motherboard at one point. Turned out the new chips just ran that hot!

Those Athlons make for a good cooking plate:

https://www.youtube.com/watch?v=atBb9JruXBw

Back when I was starting to build PCs, the heatsink application step was the scariest. I had read SO MANY horror stories. When it came around to actually doing it (on one of those naked die Athlons, no less), I made sure to read the instructions a few times. I didn't have to pray or sacrifice a goat, but I've never fried a CPU.

Story reminds me of the time that I literally squished a CPU with a fan. Being fairly inexperienced with those things, I had somehow managed to turn the fan 180 degrees before forcefully attaching it to the CPU. I even remember the hassle involved in making the little power wires extend all the way to the far side of the fan but at no time did my brain enter the loop.

Took the CPU back to the store the next day to complain that it didn't work and it took them about epsilon seconds to figure out what had happened. I bought a new CPU and hastily left the building. They must have been laughing at that for days.

This is partly why I had historically gotten everything else in place before messing with the heatsink/fan. Those older ones could be really touchy and I was petrified of crunching the exposed die of one of those older processors by having to remove or otherwise futz around with the mount after getting it attached.

One time I really did think I heard a crunching/grit type sound when mounting a heatsink and my stomach dropped out until I got the system powered on and verified that nothing was broken.

Seriously, these things were terrifying to mount a heatsink on back in the day with the way that thing sticks out, rubber pads be damned: https://i.imgur.com/6w1oVMS.jpg

My expensive cpu lesaon. The person that designed lga 2011 had the brilliant idea to make notches on the cpu almost symmetrical. So it is possible with juuuust a tiny bit of force to put it the opposite way.

Ah, you're the guy why newer LGA2011 caps come with a yellow-red warning sticker about "NOT USING ANY FORCE"? ;)

My parents used to have some "junk" computers out in the garage. One of them had a Cyrix 486 clone. These are the pins on that guy: http://www.amoretro.de/wp-content/uploads/cyrix_cx486dlc-40g...

While trying to get as many of those machines working as possible, I unseated the CPU (can't remember why), and I guessed the orientation wrong when putting it back into the machine. I don't remember seeing or smelling any literal magic smoke, but it must've gotten let out, because that machine never booted again.

Luckily, that wasn't any kind of new hardware. I've got an active imagination though, and it always comes to mind when I am working with new and expensive equipment.

I miss old PGA CPUs like that. They'd inevitably get bent, and you could almost always use the tip of a mechanical pencil (with the lead removed) to bend things back into almost exactly the right place and boot the machine. Nowadays everything is LGA and if you bend one of the tiny in-socket pins you're just sunk.

I liked clicking down the locking arm. It made a satisfying click, after an equally-satisfying increase in tension. A lot of the LGA ones now make a sickly-sounding "crinkle" that I've never liked much.

AMD is still old school and uses PGA sockets, at least for their desktop parts. I wish they would get with the program (they have for their server CPUs).

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