The last fanless CPU to be manufactured?

[Rancor]

I remember 386 and 468 processors from the 90s were fanless with puny heat sinks. I think their power draw was between 1- 6w depending on model. I am not sure if TDP was used as a metric at that time. Does anyone know the last desktop CPU to be made without a fan?

I am curious about its TDP and at what point intel/AMD started adding a fan to their processors heatsink.

Curiously the chipset on a modern A320 AM4 motherboard has a tiny (relative to old cpus) passive heatsink and uses 6.8w. Looks like the X370 chipset has the same power draw but a bigger heatsink. I guess the A320 isnt expected to reach the same wattage.

 

[whm1974]

Aren't the Atom base CPUs fanless? The last CPU I had that was fanless was an 486SX CPU which was a 486 with its FPU disabled.

 

[Rancor]

I have seen some Atom ITX boards that were fanless, but they had massive heatsinks on those boards. I am not sure what has appeared more recently. Looking at AM4 chipsets again, I see some B350 boards with itty bitty heatsinks. They seem to grow in size when the sink is shared with the M.2 SSD.

 

[Eug]

My 2017 MacBook is fanless. Not a desktop but it’s faster than most of the Atoms out there.

 

[dark zero]

And how about the heatsinkless?

 

[Fanatical Meat]

Every singe phone chip is fanless

 

[Eug]

Every singe phone chip is fanless

Indeed, and the current ones are fast enough to run a light desktop.

 

[SPBHM]

hmmm, with how well thermal throttling works, can't you run a x68 CPU without crashing without any heatsink?

specially those atoms that already run with just a thermal pad and no airflow

 

[Rancor]

hmmm, with how well thermal throttling works, can't you run a x68 CPU without crashing without any heatsink?

Interesting question and something I have wondered myself. This is an oldie but a goodie, from a time before AMD had thermal throttling. It would be fun to know just what we can get away with on modern CPUs. Imagine if you will, performing basic tasks such as web browsing and not significantly degrading the processor.

 

[mikeymikec]

Aren't the Atom base CPUs fanless? The last CPU I had that was fanless was an 486SX CPU which was a 486 with its FPU disabled.

Yup, I encountered a Celeron N4070 in a desktop of all places recently, no fan. The heatsink was about the size of a credit card with a 2-2.5cm depth I think.

Whether it could outrun a 486 is another question God I hate netbook-class processors. Even with a fresh install of Win10 and an 860 EVO, performance was still underwhelming.

 

[arandomguy]

And how about the heatsinkless?

The CPU itself is rather broad category, so in that sense there current CPUs that run without fans nor heatsinks.

In terms of maybe more along the lines of what the OP was asking historically some 486s (486 had a lot of chip variants eventually scaling up to 100mhz) had sections in their hardware manuals addressing configurations with no heatsinks (as in what airflow and ambient temperature conditions were required. The 486DX2 manual I believe specifically references having a heatsink.

So at the latest at least some 486s (they ranged form around 2w-5w average power consumption depending on the variant I think) in terms of official specifications were able to run heatsinkless depending on user conditions.

Roughly speaking I believe you're looking at about 2w-3w per 100mm^2 to run passively with no heatsink in typical home PC environments.

 

[epsilon84]

The Core m3 chip in my Surface Pro is fanless, I think the i5 model may be as well though I'm not entirely sure.

I think the way it is designed, the entire chassis of the tablet acts as a 'heatsink' of sorts.

 

[Topweasel]

Yeah I get the point of this but it doesn't really apply to reality. Back in the day CPU's had much high tolerances with the process being so large that they could get away with higher temps and in general used a lot less power then the potential on today's CPU's. But in theory every CPU is fanless. They have a max power usage that power usage determines how much thermal energy it needs to dissipate. If that can be done with just the heat-spreader than no heat-sink needed. All CPU's at any power level can go fanless by using a heatsink big enough to dissipate that much energy naturally without a fan.

 

[Eug]

The Core m3 chip in my Surface Pro is fanless, I think the i5 model may be as well though I'm not entirely sure.

I think the way it is designed, the entire chassis of the tablet acts as a 'heatsink' of sorts.

The MacBooks use Core m3, i5, and i7 Y-series all with TDP-up (so higher power usage than standard) and all are fanless.

That said, the real-world performance isn't always all that different between the various chips of the same Y generation, due to thermal throttling.

In this test, three of us in internet land ran Cinebench repeatedly for over half an hour to see the effect of thermal throttling. I had the m3, and others had the i5 and i7. "wood" is my Core m3 on a wood table, and "granite" is the same m3 on a granite counter that would wick heat better.

The x-axis is the Cinebench score, and the y-axis is the run number.

As you can see, my m3 on granite does better than the i5 on a regular table. Note though that the deltas look bigger than they really are, since my x-axis only spans 210-280.

If you start the x-axis at 0, then the performance difference looks much smaller.

That second graph goes past run 10 but for the first graph I chose to stop at run 10 because things happened at run 11. For example, the i7 owner got a call during run 11, which screwed up the test result for run 11. In my case in run 11 I moved the MacBook and just doing that meant a higher score the next run, because the new spot hadn't been heated up yet.

 

[John Carmack]

I remember 386 and 468 processors from the 90s were fanless with puny heat sinks. I think their power draw was between 1- 6w depending on model. I am not sure if TDP was used as a metric at that time. Does anyone know the last desktop CPU to be made without a fan?

I am curious about its TDP and at what point intel/AMD started adding a fan to their processors heatsink.

Curiously the chipset on a modern A320 AM4 motherboard has a tiny (relative to old cpus) passive heatsink and uses 6.8w. Looks like the X370 chipset has the same power draw but a bigger heatsink. I guess the A320 isnt expected to reach the same wattage.

I think they started adding them in the latter 486 days. I know Pentiums had fans and those were probably 10W and up.

Intel's Core M (Y series) are ~5W TDP capped big Core chips which can run fanless in small laptops and tablets. On desktops with large heatsinks you could passively operate one most likely if you capped clockspeeds low enough.

 

[arandomguy]

486s ranged from ~2w to 5w+. So the lower power/lower clocked ones were able to run even heatsinkless (bare) depending on other conditions.

 

[thecoolnessrune]

And how about the heatsinkless?

I would say it depends on the tier.

If you say solidly, you don't need one, I think the last tier was the low power (3.3V) Intel DX4 486's. Those ran up to 100Mhz and didn't need a fan or heatsink.

If you say, "well ignore what it might say on the chip", then VIA C3 667 Mhz chip had a TDP of only 2.5 Watts, and even though some variants said "heatsink and fan required" on the IHS, they were very often run in embedded applications without any sort of heatsink or fan.

If you grow the policy to any architecture, then there's plenty of chips running without a heatsink or fan to this day, one of the more obvious being the CPU used in the Rasperry Pi, with this year's quad core variant being the first to even add an Integrated Heat Spreader.

 

[LTC8K6]

I wonder what my 4790K would do with a big fanless heatsink and good case airflow?

Or maybe a 4790T?

 

[thecoolnessrune]

I wonder what my 4790K would do with a big fanless heatsink and good case airflow?

Or maybe a 4790T?

Even just a smidgeon of airflow from even the quietest fans can make a big difference. But that said, the Heligon HE02 v2 is good for up to 95 watt TDP fanless (and 150 watts+ with a fan). It's massive, but it shouldn't have any issues with a 4790K as long as it isn't overclocked, and it's been around for years.

 

[LTC8K6]

That's way too big and heavy. Far more than I imagined. A kilogram...

 

[thecoolnessrune]

That's way too big and heavy. Far more than I imagined. A kilogram...

From a pure physics standpoint, with some assumptions, it takes about 18 cubic meters of surface area to keep a 4790K at sustained wattage from overheating with no air flow. There's obviously reductions when adding airflow, and the fact that a CPU should not be at 95 watts all the time, but still, it takes some surface area!

 

[bbhaag]

I would say it depends on the tier.

If you say solidly, you don't need one, I think the last tier was the low power (3.3V) Intel DX4 486's. Those ran up to 100Mhz and didn't need a fan or heatsink.

If you say, "well ignore what it might say on the chip", then VIA C3 667 Mhz chip had a TDP of only 2.5 Watts, and even though some variants said "heatsink and fan required" on the IHS, they were very often run in embedded applications without any sort of heatsink or fan.

If you grow the policy to any architecture, then there's plenty of chips running without a heatsink or fan to this day, one of the more obvious being the CPU used in the Rasperry Pi, with this year's quad core variant being the first to even add an Integrated Heat Spreader.

I have an old DTK 486 system with an Intel dx4 100 in it. Its just has the ceramic lid no heatsink or fan to keep it cool. Even the case doesn't use any fans to help with venting heck the only fan in the system is the one in the psu.
If we are talking old school x86 then ya I think fanless ended with the 486. I know Pentiums needed a fan and sink to cool them. Even the Pentium Overdrive 83mhz cpus that converted your 486 based system to Pentium like system used an integrated sink and fan to cool them. I have one in my DEC system and love watching that POD fan spin up. haha

Anyway, getting a little nerdy but to get to the point. If we just stick to the x86 architecture then fanless ended with the 486 and began again with the Atom. If we want to open this up to any cpu that can run fanless then the list grows exponentially.

 

[DethGasp]

The last fanless CPU I had in a PC, was a Gateway 2000.
It came with a Pentium 233 MMX, 32MB RAM and a 1GB Quantum Fireball w/W95B.

 

[mikeymikec]

The last fanless CPU I had in a PC, was a Gateway 2000.
It came with a Pentium 233 MMX, 32MB RAM and a 1GB Quantum Fireball w/W95B.

Huh. The P166MMX I had with a HSF absolutely cooked (I didn't check temps but the heatsink was hot enough to burn if I left my finger on it), IIRC.

 

[DethGasp]

Huh. The P166MMX I had with a HSF absolutely cooked (I didn't check temps but the heatsink was hot enough to burn if I left my finger on it), IIRC.

Mine ran pretty cool until the PSU fan died (only fan in the system).
Than I had to zip-tie a fan on the HSF since the unit I bought to replace the old PSU had a 80MM exhaust and no intake. But now that I think about it, I use to get regular BSoD's before I put a fan on it. It was either overheating or W95 was just being itself.