Fastest CPU without a heatsink/fan/cooler?

[JeremyF50]

After a previous thread I started I learned that after about the 486SX CPUs started including heatsinks, and later fans on those heatsinks.

From what I can tell, it seems the TDP limit for these heatsinkless processors is 3-4 watts. I'm not sure whether you can dissipate much more heat than this without a heatsink - I personally don't have much experience with such old tech.

I've seen a video of a Via C3 800Mhz running without a cooler on youtube supposedly playing quake 3 heatsinkless for 24 hours - but I don't know if this is true. It's an 8.3W 1.35W TDP chip. I have read a couple of reports online about the earlier/slower C3 chips being able to run without heatsinks - but they were higher volts than their successors around the same clock speed (1.6V vs 1.35V).

The 667mhz C3 has a TDP of 2.5W and the 733mhz has a TDP of 3W. These are the Max TDPs and not the 'typical use' TDPs apparently. I know these chips are slower than the equivalent Pentium 3 or Celeron, but surely these are faster than the 486SX without a heatsink.

The Pentium 75 and Pentium 90 might run cool enough to forego a heatsink - but again, the C3 would be faster.

I've also looked at AMD's offerings. There's 8-9 watt TDP chips at 1GHz single core Athlon 64s with 512kb cache. You could probably drop the multi from 5x to 4x (which i believe is the lowest) then drop the fsb down, then the voltage and run heatsinkless at 400-600mhz. Similar might be possible with a Pentium M. A Sempron might be better than the athlon due to less cache so less heat/power.

The Athlon64 seems to have a bigger IHS to absorb heat than the 478/775 chips - and mobile chips like the Pentium M have no IHS at all...

Not sure whether the ceramic packages will absorb more heat than the later metal IHS chips.

I'm just curious really. If you have anything to contribute, please chirp in!

 

[jaqie]

you can run a severely undervolted underclocked core2 duo 45nm wolfdale without a heatsink, but the thing runs like a slug, as you might expect.

486DX40 was the last intel cpu I know of to come without a heatsink. the DX50 (not the same as dx2/50) required one though not everyone used it, and the dx2/50 had one IIRC.

There was an IBM/cyrix processor known as the 486BL75 it was essentially a super hopped up 386 dx3 75MHz, it was in a tiny PLCC package and it ran without a heatsink sometimes as the dinky one that was glued onto it came off sometimes without knowledge of such.

Nowadays the only ones regularly running without heatsinks are the ones in routers, most commonly MIPS and older ARM architecture. Those MIPS get over 200MHz without a heatsink, some 400.

 

[JeremyF50]

you can run a severely undervolted underclocked core2 duo 45nm wolfdale without a heatsink, but the thing runs like a slug, as you might expect.

Have you actually done this with a wolfdale chip? I imagine a celeron would be better for this being one core and having less cache.

 

[jaqie]

wolfdale is a core revision/type, not a sell brand. I have had three wolfdales, all celeron subtype. E3200 was one of them. I dont remember the other two, but there was one 2.2ghz one 2.4ghz and one 2.5ghz all wolfdale core celerons.

 

[JeremyF50]

I was referencing the E8000 series. I was going to say Penryn as that's how Intel liked to reference 45nm but meh. I stand corrected though

 

[ShintaiDK]

You cant run Pentiums or above without heasinks. Basicly the only Intel CPUs that can do it without heatsinks is certain Atom CPUs today. Rest would throttle without a heatsink/fan, unless modified in speed.

 

[Insert_Nickname]

You cant run Pentiums or above without heasinks. Basicly the only Intel CPUs that can do it without heatsinks is certain Atom CPUs today. Rest would throttle without a heatsink/fan, unless modified in speed.

Considering how little power a Celeron/Pentium actually uses, it -could- properly run without a fan IF the heatsink is large enough and there is sufficient airflow in the case. My G465 rig has a max powerdraw of ~10-12W (according to HWmonitor), so it seems possible. Haven't tried running without the fan though. But it does run fine (e.g. no throttling) with a standard Intel heatsink with the fan at an absolute minimum RPM.

 

[Maximilian]

Well this is a 12 year old video but its relevant, unless something happened since 2001 then intel chips (probably AMD's too but until someone trys it....) should run without a heatsink without frying themselves.

http://www.youtube.com/watch?v=y39D4529FM4

Unless they ditched that rather impressive throttling technology after the pentium 4.

 

[Charles Kozierok]

Considering how little power a Celeron/Pentium actually uses, it -could- properly run without a fan IF the heatsink is large enough and there is sufficient airflow in the case.

Right. There's nothing magical about running without a fan, you just have to drop the power dissipation and use a good heatsink. Companies have done this with mobile and embedded devices for ages.

VIA has several chips designed to run without fans. Of course, they're really slow.

 

[86waterpumper]

the DX50 (not the same as dx2/50) required one though not everyone used it, and the dx2/50 had one IIRC

HAHA I remember where I work now, when I started there, everyone had just gotten pentium rigs, and they still had a old dx2/66 (overclocked to 80) 486 machine sitting around but it didn't get used for alot other than storing old files etc. We ran it for a long long while with just the heatsink, because the fan stopped working, and then one day someone stole the heatsink for a project or something else, and it kept running that way a long time with the bare chip! I'm sure it wasn't good for it, you def. couldn't hold your bare hand on it, but the computer did run without freezing or locking up etc.

Athlon thunderbirds with the exposed cores were the worst...those things would fry nearly instantly without a sink...

 

[dave_the_nerd]

I wouldn't WANT to run an older CPU without a heatsink, even if the thermals looked okay, because they didn't have the auto-throttling circuits that keep them from immolating themselves.

http://www.youtube.com/watch?v=vQG1Lr1DmZk

Newer chips (C2Ds for sure, I know) will slow down as needed.

www.youtube.com/watch?v=C4YPcDeyYd0

 

[Exophase]

What counts as a heatsink? My Exynos Chromebook has a heat spreader but people tend to refer to that separately from a heatsink.. and it's way more powerful than an old 800MHz C3.

Not sure how fast it could reliably run w/o the heat spreader and w/o throttling.

 

[kjknight]

There was a thread on XS quite a few years back about running a core solo at 1ghz and undervolted without a heatsink. I haven't seen anything recently doing the same thing.

 

[Shephard]

Well this is a 12 year old video but its relevant, unless something happened since 2001 then intel chips (probably AMD's too but until someone trys it....) should run without a heatsink without frying themselves.

http://www.youtube.com/watch?v=y39D4529FM4

Unless they ditched that rather impressive throttling technology after the pentium 4.

ah yes the classic video.

proof that Intel cpus are better quality than AMD.

 

[JeremyF50]

Thanks for the links and references guys. I checked them all out, including the XS article. I've got a fair idea of heatsinkless cpu operation now. Might come up with my own little project to try. If i do - I'll post my results

 

[Maximilian]

Newer chips (C2Ds for sure, I know) will slow down as needed.

www.youtube.com/watch?v=C4YPcDeyYd0

Looks like athlon X2's will do this as well:

http://www.youtube.com/watch?v=0gF3AkjYehI

I like how in both vids the guy pokes it to test the temperature, safety first :awe:

Well there you go OP, its likely the fastest CPU without a heatsink is the 3970X or one of the beastly 8 core xeon versions of it.