Hot CPU
 

It's been record-breaking hot here in our part of the world.

As having the a/c on all day dries our throats out, we occasionally switch it off whereupon the living room temperature rises to 30º.

I keep an eye on my CPU temp (AMD Athlon 64x2 dual core, ducted air cooling from outside the PC) and it gets to around 50º, maybe 52º on one core, the other a few degrees less, under these conditions.

I've tried all manner of additional cooling systems, some of such stupendious primitive construction (taking blanking plates off front of PC and fitting a 12v fan to blow air into the case) that I won't reproduce photographs here. None had any effect.

Putting the a/c on gets thr room down to 26ºc and the CPU drops to around 48º max.

Pending the usual autumnal rebuild (and cleaning of cooling fins !) are these temperature differentials between ambient air and CPU temps. normal ?

Depending on the processor, the manufacturer, how fast it runs, where the sensor is located, and what programs it is currently running will determine the temperature of what the processor should be. However, this document should give you a general idea of what the processor should be running at as well as what is acceptable and what is not.

The majority of today's desktop processors should not exceed temperatures of 95C and most will run between 70-90C.

Taken from: What temperature should my processor be running at?

Thanks GG. Next rebuild will include extra case fans, I have several salvaged from deceased PC's.

AMD 64 X2:

Maximum CPU Temperature | Hardware Secrets

Depending on the specific CPU, your limit will be from as low as 63 up to 72.

I've got three of these, all 89W units, usually in the 30-40 degree range, all with stock AMD cooler & fan. One PC CPU does tend to get noticeably hotter than the others in the summer - I'm not sure if this is an airflow or thermal paste problem - and the fans are definitely busier as a result. Still only gets up to 51-52, ambient around 28.

SD

Still only gets up to 51-52, ambient around 28.

Sounds like mine, time is 22:45 now, CPU is 51ºc, ambient is 30.3ºc.

(And five forest fires burning around us, normally you can rely on one wind direction at last being smoke-free, not tonight).

I wouldn't worry about it. If you have a decent CPU cooler, just let it do its job - if it's too hot, it will throttle or shut down. I have also yet to find a CPU (Pentium 2, 3, 4, Athlon XP, Pentium M, Core duo, Core 2) that cannot withstand temperatures of at least 80 degrees.
I run an AMD powered server in my loft and it is often 35 degrees in there in the summer - fans make a racket (can't be heard outside of the loft though!) but it continues to work just fine. No idea of CPU temps. :ok:

Celeron and Pentium "D" models were the main problem. They burnt so much electricity that there was little in the way of cooling overhead if the fans got clogged, and fried boards were a common result

The other ones to watch for were early Athlons as these had no thermal cutout built into the CPU. It was easily possible for them to catch fire

I took two blanking panels off the front of the PC, which obviously allows more air in, and the temperature has dropped about two degrees. I've got two spare fans here and Any Time Real Soon (tomorrow if I get bored) I'll fit 'em, probably one in the back sucking out and one in the front sucking in.

probably teaching you to suck eggs, but while you're at it make sure the airways through the PSU are clear. Vacuum them out

Computer back on line after check - not nearly as dusty inside as I thought it would be although leading edges of CPU cooler fan covered with a sort of greasy dust (!) that needed scraping off. Fitted an extra fan on the outside of the case to blow air into the CPU cooler duct, this fan runs all the time (very quiet 12v) so keeps a flow of external air to the CPU even after the off or standby switch is pushed and reduces the rise in CPU temperature as the internal CPU fan shuts down. Core temps now about 5º cooler although cooler weather is playing its part.

"sort of greasy dust"

any smokers in the house?
or possibly shed dog or cat skin /dander

both can cause that kind of effect. Together they're lethal for a PC

No smokers, no cat any more (sadly missed), kitchen is three rooms away and that has an extractor fan. But we do (aha !) have a woodstove in the living room.

BTW when I bolted the Machine back together I found I had one USB cable left over without a socket to plug it into. Highly mysterious. Are aliens stealing USB sockets ?

Off to PC Box on Monday to buy an additional USB card to fit into the rear.

Thanks for everyone's suggestions.

woodsmoke could well do it
And your comment about the kitchen is also: thats a real risk to laptops, which tend to get used on kitchen worktops. Hot airborne fat and grease can get everywhere inside

Not to be mentioned to the Mem'.

First consequence: "Are you saying I don't keep this house clean ?"

Second and far worse consequence: "I told you we need the living room (and..) redecorated."

Looked into water cooling for the new Draper home made super puter but they seem to be designed for tower cases and one built this one in a desktop case for a change.
:(

I have also looked at water cooling but wonder whether they ever leak, because if so the consequences would be serious

A question: every form of CPU cooler (air or water) relies on blowing ambient air over some form of cooling fins. There is obviously a limit to just how much coolth you get out of ambient air, and the hotter the ambient air is, the less CPU cooling you are going to get....I wonder what the lower limit is (i.e. the maxium cooling) you can get out of still air ?

Sure, magazines often publish tests as to which is the most efficient cooler, but there is always going to be a limit imposed by ambient air temperature.

Mr D: some months ago I accidently bought a "build your own PC" magazine intended for gamers. Inside was a mega test on CPU coolers. Surprisingly the water coolers didn't come out best. Considered pricey, cumbersome and not offering that much of an advantage if any over pure air coolers.

If I may beg indulgence from the Mods, the recommended best buys were as follows:

For the AMD and the Intel CPU, the Thermaltake Frio

For the Intel CPU and you want quietness, the Cogage Arrow

OFSO

you need one of these, although they don't seem to make them any more. :{

Thermaltake XPRESSAR RCS100 Micro Refrigeration Case at Xoxide!

But as competent shed owners, you could do this:

Extreme Water-Cooling Using Refrigeration | Overclockers

Yeah, GG, that's more like it and seems the only way to go with ambient air over 30ºc - in fact our swimming pool (no heating, the water is just lying there indoors but in the sun, big windows) is also over 30ºc.

I have a small solid-state cooler box (12v dc or 220v ac) which would be ideal, in fact I did consider taking the cooling unit out and fitting that in my ATX case, until I realised how much condensation water drips off the Peltier fins on humid days ! The ATX case and the cooler box are about the same size and beer gets VERY cold in the cooler box, so this would be ideal in the ATX, fitted with a drip tray and pipe to the outside. Maybe a brass pipe.....oak drip tray...brass header tank with nice analogue contents dial over it...rotary brass handle to top up water tank....I feel an attack of steampunk coming on.

I just disabled AMD's "cool 'n quiet" and can detect no difference to the cool or the quiet. Anyone else found this ?

re liquid cooling systems
I've seen several which leak, and all the rest seem to lose fluid through evaporation.
The leaks aren't helped by the fact that the cooling solution is usually a water / glycol mix and seems to find weak joints very easily.
Topping up the reservoir can be a right PITA, especially if (as on some) the system doesn't prime properly and you have to try to draw out the air locks by bending / twisting the pipes.
Not worth the grief in my opinion

I'm in an environment which appears to be vastly hotter than　OFSO's. The only thing I do is make sure a machine is not sitting on a hard surface: if you can space it a couple of cm above the hard deck, convection will take care of the rest.

I've also converted a couple of machines to liquid cooling. Only for the experience, I didn't think it had any absolute benefit until recently. Right now, I'd go for liquid cooling simply because it leaves the case generally uncluttered, and you get a good exhaust fan for free. I've never had a liquid system leak, even in the early days when I used them simply to say I had one. In my particular case, the graphics cards are a greater concern than the CPU. The CPU is the low-cost bit.

Finally, CPU's are cheap. Why not have one in stock?

The heat sink on my CPU (AMD Phenom 3.6 Ghz Quad Core) has a arrangement of copper pipes running through it,one assumes they has some kind of fluid in them in a closed system came with the CPU when I bought it,pretty heafty fan as well.
:)
Did install a couple of extra four inch fans as well,but it proved to be irritatingly noisy so I took em out,
Of course a lot of cooling is achieved by the case not having a lid,dont believe in lids, built a one that didn't have a case once,worked fine for years.
Behold :rolleyes:
http://i11.photobucket.com/albums/a1...0-42-05304.jpg

depends on the machine and case design, but leaving it open can actually impede the air flow and - counterintuitively - hinder coolng

PCs depend very much on a directional air flow, in through one vent, over the CPU/GP, then out via another. On older machines the PSU was the exit, newer ones via a rear vent. The actual internal routing depends on whether the system is ATX, mATX or BTX. But it all boils down to one thing - on a properly designed system taking the side panel off can actually make the machine run hotter

I notice in that photo that there appears to be no exhaust fan, and the CPU fan isn't ducted to the outside, so in your case, taking the side panel off may help.
As for those copper heatpipes - I think you'll find they're solid copper

Had a four inch fan on that side vent plus one on tother side when I first built it but as I said it sounded like a Phantom spooling up so I dumped em with no ill effects temperaturewise.
:)
Hmmm prompted to take a look due to this thread I reckon tiz time I unhooked the heat sink/fan and give em a good scrape out again.
:uhoh:

never a good idea to remove the heat sink unless you really need to, especially with AMD CPUs.
With the AMD designs theres too much chance of the thermal paste acting like glue, and ripping the CPU out of the socket - possibly killing the board.
Intel designs aren't so much of a problem, though some motherboards object to having the heat sink twistlocks removed and reseated too many times

Been building me own puters since the days of the 486 Mr Milo, I know how to remove and replace CPUs/heatsinks, the one in the photo has been yanked and cleaned twice since it was built.
Only ever had one CPU fry itself on a grossly overclocked pentium, fan was stalled by the IDE cable,mind you it did die very swiftly,spotted what had happened almost instantly and grabbed for it but too late.:(

Just a stray thought, unless you are running a dp center or doing heavily numerical finite element analysis, do you really need all that computing power?

I'm writing this on a teeny 7" mid tablet and it doesn't even get warm. Arm/risc/linux/android-gingerbread.

Micellaneous Cooling Issues

We used to have thick copper buses on all boards to conduct heat away from chips because there's no convection in zero-g and the fans might fail.

I dimly recall reading of piped sulfur as a cooling medium. Don't try this at home.

Coolth may best be found in your dungeon and accessed by airflow through donkey dick or piped liquid through car radiators with fans. Biggest problem is trapping condensation.

Aerospace parts may have wider temperature specs but they tend to lag behind domestic parts.

Milo
 

Not sure I understand your post:
Why would the Mboard be killed with no power?

Like Tony I've built (asembled I mean) computers from the 486 up. They are just a poor mans meccano set.


Regards
Exeng

socket physically fractured

seen it happen several times, with AMD chips, where the CPU is ripped from the socket even though the CPU retention clip arm is still down. Result is the socket can fracture, or in some cases be partially pulled from the board.
The heat transfer stuff (especially the silver colloid types) can simply stick too hard. One way round it is to release the tension clips on the heat sink, and then cut through the heat transfer medium by passing fishing line under the heat sink.
Can't happen with Intel CPUs because of the way they have a kind of retention "shield" over the socket, stopping the CPU pulling away.

Thats an AMD CPU he's got there

Milo,

More recent AMD Opteron CPUs have used LGA format (socket F, C32, G34) with similar CPU retention clips to intel - I expect that the next generation of AMD desktop chips will do the same. The socket AM2 / AM3 architecture seems to be nearing end of life.

I've had no problems with intel or AMD ZIF sockets over the last 15 years. I've occasionally had a CPU stick to the heatsink and pull out with the ZIF lever still locked, but never any damage to the mobo or socket - or the CPU or pins.

Maybe I've just been lucky, but I'm sure that the ZIF lever is designed to apply a much smaller retaining force than would damage the socket or CPU in the event of a tug of war. I am talking about a straight, vertical pull-out force, not a twisting or rotating force here, as I'm sure that either of these could indeed damage the CPU and / or socket.

SD

Tony, looks like you could get a Peltier cooler in there AND at least two cans of beer.....

Used to peruse a overclockers website a few years back,some of their home made cooling systems were a bit far out,this was before one could venture to the puter boutique and buy exotic cooling systems orf the shelf as it were
:)

To wind this thread up (and for the benefit of anyone else with CPU cooling problems in hot weather).

My extra fan blowing air into the CPU cooler duct shows:

a marginal reduction (2º) with an ambient temperature over 30ºc;

a significant reduction (5º) w.a.a.t. under 28ºc.

a probable reduction in CPU temperatures immediately after switch off (CPU fan stopped but extra fan still running).

Conclusion: if you are bored, and you've got the parts lying around in the shed/garage/bedroom, it's worth doing.

Liquid Cooling
 

The best to use for liquid cooled systems is cheap supermarket VODKA!

The alcohol prevents algae/mould growth within the pipes.

(and you can drink the rest)

That's a waste of booze.

I add no more than a teaspoonful of ordinary disinfectant to my 2L screen washer bottle to achieve the same effect.

as I mentioned earlier, most of the cooling system manufacturers recommend (or did the last time I looked) a glycol-water mix.
I suspect ethanol may be too agressive on the seals in some systems. It certainly may not mix too well if you already have glycol in the pipework