Modern CPUs that can be passively cooled?

greigmg

Member
Jan 14, 2005
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Hey, I'm a few years out of the loop and am wondering if there are any modern processors (AMD or Intel) that can be passively cooled without taking special steps. I've got a storage box running a PIII 450 with nothing but the heatsink on it, but wouldn't mind stepping up the speed a bit. I don't want to add some monster CPU cooler to the system, though, and am wondering what the ability is these days for passive cooling.

Thanks.
 

Lonyo

Lifer
Aug 10, 2002
21,939
6
81
If you underclock/volt and you use a big heatsink, and have a cool room/good airflow you might be able to get away with it.
Also, think about looking into A64 mobile chips (for Socket 754) or Pentium M (more expensive), because (obviously) they're lower power consumption processors which may fit the bill.
 

fbrdphreak

Lifer
Apr 17, 2004
17,556
1
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Wait until 2006 when dual core mobile chips come out. They'll be pricey, but run cool & pack some serious punch
 

Zap

Elite Member
Oct 13, 1999
22,377
2
81
Here's your solution: Get the cheapest setup you can find with AMD Cool and Quiet - this means the Sempron 3000+ CPU with an overclockable motherboard. Those boards should let you lower the multiplier - go all the way down to the minimum. Undervolt in BIOS if possible, otherwise use software in Windows to undervolt. Test stability with Prime95. You can run passive easily using any heatsink designed for it, such as the Scythe Ninja (or the older Heatlane models) or the Thermaltake Sonic Tower. Heck, with a 90nm Sempron underclocked and undervolted this much, may be able to get away with nearly anything. Still, this setup should outperform that old P2 of yours by 2-3x easily.
 

DrMrLordX

Lifer
Apr 27, 2000
21,596
10,791
136
ULV Xeons might work too, but I dunno for sure. You could also probably underclock a Sempron 3000+ or 3100+ by dropping the multi to 7x
 

bunnyfubbles

Lifer
Sep 3, 2001
12,248
3
0
No need for any exotic low voltage/wattage/mobile chips as some have been suggesting. Undervolting and underclocking would be your best bet. 90nm AMDs should be a great place to start, single or dual core, depending upon what you need you'd probably just want to stick with single. Since you have full access to multipliers with AMD chips under the stock multiplier, you can just pick up a low-end A64 or even Sempron, and simply drop the multiplier and voltage in the BIOS.

However that does require some work, and depending on how good your passive heatsink, you'd need to test for stability.

No matter how you look at it, you're going to have to do something out of the ordinary to get a modern CPU to work without active cooling - whether that be undervolting/clocking, or bothering with special low wattage/voltage sever/mobile chips, or opening up to the possiblity of using a "monster" heatsink.

A heatsink such as the Scythe Ninja should be enough to cool modern chips without a fan (it was designed to do so, but also accepts 120mm fans for some crazy cooling). But it is a "monster" heatsink. Something like an XP-90 and underclocking/undervolting should work well, but that would require "special steps" to make sure of stability (well any heatsink half decent heatsink should work, but obvioulsy the better the heatsink, the less trouble you'd have messing with it). If you really want to do it, you'd have to pick a lesser of evils - competition is simply to fierce these days to produce normal CPUs that do not require active cooling
 

jazzboy

Senior member
May 2, 2005
232
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Well i can tell you that I got my 3000+ Newcastle at stock 2GHz undervolted from 1.5 VID down to 1.25 VID (about 1.56v -> 1.30v actual).

So if you can grab hold of a A64 3000 - 3700 (venice/san diego) you should be able to undervolt from the default 1.4 / 1.35 down to at least 1.2, which would easily make that cool enough for passive cooling.
 

greigmg

Member
Jan 14, 2005
45
0
0
Yeah, I'm not into any extreme undervolting, etc. I don't mind a huge heatsink, but I want to stay away from the fan purely for noise issues (small house, this thing sits in my bedroom). I think the Turion might be the way I go - on a Newegg review of one of them (I think the 1.8ghz) a guy said he had it in a desktop that was passively cooled and it worked out well.

Is there anything special to look out for when putting a Turion on a desktop motherboard - this guy mentioned to make sure it supported all the speed-stepping and such the Turion does - will any ol' Socket 754 board do or is this something I should watch out for? Thanks for all the help.
 

thecoolnessrune

Diamond Member
Jun 8, 2005
9,671
574
126
As for the Turion. Its a mixed bag. I cant tell you which boards support a Turion. But I do know that not all of them support it. Also since the Turion is lidless, it may leave a gap between the heatsink and processor, which means you will have to modify the motherboard heatsink holder just enough to get the heatsink on contact with the core. But not too hard or you'll crack it.
 

Markfw

Moderator Emeritus, Elite Member
May 16, 2002
25,534
14,482
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Originally posted by: greigmg
Yeah, I'm not into any extreme undervolting, etc. I don't mind a huge heatsink, but I want to stay away from the fan purely for noise issues (small house, this thing sits in my bedroom). I think the Turion might be the way I go - on a Newegg review of one of them (I think the 1.8ghz) a guy said he had it in a desktop that was passively cooled and it worked out well.

Is there anything special to look out for when putting a Turion on a desktop motherboard - this guy mentioned to make sure it supported all the speed-stepping and such the Turion does - will any ol' Socket 754 board do or is this something I should watch out for? Thanks for all the help.

I have two X2's with XP 90's in my bedroom in Sonata cases. Can't even hear them. I went with fanless wimpy video cards, since these are for work though, and went with a big heat sink for the north bridge, and of course the Sonata is almost the quietest case made (arguably)
 

2kfire

Senior member
Nov 26, 2004
246
0
76
If you have a case with good cooling and a good heatsink, you should be able to run a pretty high-end CPU passively. I have a Sonata II (not the best case for cooling), a thermaltake Sonic tower, and I run my Athlon 64 at 2.43 GHz with no fan on the cooler. Here is a post I made when I first got the cooler: Thermaltake Sonic Tower
 

greigmg

Member
Jan 14, 2005
45
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0
Originally posted by: Markfw900

I have two X2's with XP 90's in my bedroom in Sonata cases. Can't even hear them. I went with fanless wimpy video cards, since these are for work though, and went with a big heat sink for the north bridge, and of course the Sonata is almost the quietest case made (arguably)

Originally posted by 2kfire

...and I run my Athlon 64 at 2.43 GHz with no fan on the cooler.

Hey Mark, any fans on the XP90s? These both sound like the type of setup I'm going for - I assumed the mobile chip might be the only thing cool enough to run passive, but after reading about the workhorse AMD 64 3000 (446 reviews on newegg!) it looks like I could go with that with one of these giant coolers. The processor won't be doing much at all to produce any heat.

Hoping to find a motherboard with onboard video (I usually use remote desktop to control the thing anyway, rarely ever run a monitor off of it). Guess I should've mentioned the case this all goes into - uATX Coolermaster w/ a 120mm front fan and 2 80mm rear fans - right now running just one 80mm rear, but willing to put in the rest and run all at low speed. Don't plan on overclocking.

I'm glad to see some of these midrange processors are still relatively efficient - last computer I put together was a socket A Athlon 1.2ghz, overclocked a tad, which had some loudass fan sitting on top of it. Was loud (cheap case, too).
 

Zap

Elite Member
Oct 13, 1999
22,377
2
81
What you may also want to try doing is along with the other suggestions regarding CPU and underclock/undervolt, try running a reasonable heatsink and a slow fan. A Panaflo "L" fan undervolted to 7v would be inaudible inside a case, let alone a case with 120mm front and 80mm rear. Those fans would be noisier than the Panaflo "L" undervolted, plus having a fan at all on a CPU cooler will increase cooling by quite a bit, unless you duct air to/from a case fan. That's also a thought, to make a duct from the heatsink to an existing fan such as your rear case fan or the PSU fan. Best bet would be a "tower heatpipe" style heatsink.
 

Markfw

Moderator Emeritus, Elite Member
May 16, 2002
25,534
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Originally posted by: greigmg
Originally posted by: Markfw900

I have two X2's with XP 90's in my bedroom in Sonata cases. Can't even hear them. I went with fanless wimpy video cards, since these are for work though, and went with a big heat sink for the north bridge, and of course the Sonata is almost the quietest case made (arguably)

Originally posted by 2kfire

...and I run my Athlon 64 at 2.43 GHz with no fan on the cooler.

Hey Mark, any fans on the XP90s? These both sound like the type of setup I'm going for - I assumed the mobile chip might be the only thing cool enough to run passive, but after reading about the workhorse AMD 64 3000 (446 reviews on newegg!) it looks like I could go with that with one of these giant coolers. The processor won't be doing much at all to produce any heat.

Hoping to find a motherboard with onboard video (I usually use remote desktop to control the thing anyway, rarely ever run a monitor off of it). Guess I should've mentioned the case this all goes into - uATX Coolermaster w/ a 120mm front fan and 2 80mm rear fans - right now running just one 80mm rear, but willing to put in the rest and run all at low speed. Don't plan on overclocking.

I'm glad to see some of these midrange processors are still relatively efficient - last computer I put together was a socket A Athlon 1.2ghz, overclocked a tad, which had some loudass fan sitting on top of it. Was loud (cheap case, too).


If you get an XP90 with a chaintech VNF4 util like I just did, even with a high speed fan, it is on auto, so the fan runs ar 900 rpm, and you just can't hear it ! And that is at 1.425 volt 2400. Right now I am at 2500 and 1500 rpm, and I still can't hear it over the sonata 1 case right beside it, and thats not as noisey as my Dell 270 at work ! At default vcore, it woud certainly run 900 rpm or less ! (maybe I will play with it )
 

2kfire

Senior member
Nov 26, 2004
246
0
76
Originally posted by: AkumaX
i ran a Sonic Tower on an 820D at 85*c, idle.

:Q
How was your case cooling? Also, for a Pentium-D, a fan (even a low speed one) would be highly recommended, unless you have REALLY good airflow in your case.
 

mindwreck

Golden Member
May 25, 2003
1,585
1
81
completely passive with just a heatsink i dont' think you should unless you good airflow. With my watercooling and everything fan off it gets pretty toasty at 55-60C
 

AkumaX

Lifer
Apr 20, 2000
12,642
3
81
haha, here's the rest of the story:

I only ran it at that temp for 3 hours (went to school and came back, then I realized :Q:Q:Q:Q

So I added a dinky little quiet 80mm fan in the center and now my idle temps are 44c, load 54c

Airflow you say? ummm... --- sure.... :D

edit: and just in case you missed it, Big Typhoon looked like this , with temps of 53c idle and 73c load