Author Topic: Temperature and Performance (Read 829 times)

SilverFox · « **on:** November 10, 2004, 01:00:36 PM »

This is intended to seed a discussion on temperature and its impact on performance. I'm suggesting that not enough discussion occurs among AH pilots concerning this issue, while it gets much attention among other hard core gaming communities. Hey, we're gamers, we can talk temp too.

As I monitor my system temp in three ways I notice a definite and not surprizing increase in system temp during game play. I noticed a cpu heatsink temperature rise from an unloaded 80° F (26.6°C) to 91°F (32.7°C) after an hour of flying. A stick on termometer inside the case indicated a 5° increase. And the video card software shows an increase of 8°F The increase in temperature carries over into the inside the box (ambient) and other components contribute to the problem.

There are lots of solutions to temp buildup out there, some as simple as replacing the flat ribbon cables in your machine with round cables. Fans are cheap and most cases accomodate more fans than they come with. And as an extreme, to suggest how serious the gaming community at large is becoming, some folks have tried to submerse their mobo's in liquid nitrogen. (don't try this at home boys and girls) Its just to illustrate.

So I've included a couple links to provide a technical read on the subject, and welcome comments, on solutions people have found. One company for instance provides a unique video card solution that exhausts air through the case slot adjacent to the video card.

So my main point is this. Keeping the system cool will boost performance.

http://cache-www.intel.com/cd/00/00/06/20/62085_62085.pdf

http://www.amd.com/epd/processors/6.32bitproc/8.amdk6fami/26.amdk62e/21085/21085.pdf

indy007 · « **Reply #1 on:** November 10, 2004, 01:19:24 PM »

A couple of important factors in it to keep in mind.

I've personally found it better to create a negative pressure in the case, creating a vacuum effect. Simply, more exhaust fans with a higher CFM rating, and fewer intake fans. Wire management is also important to take the biggest advantage of this (remove unneccessary power wires, switch to rounded cables, sleeve every cable you can, keep everything nice & tidy).

The temperatures your motherboard and software tell you are not always right. They're measuring the temperature of the air moving over the thermometer, which is often under the processor itself. If you have replaced your standard cpu fan with a much higher rated one, you can get erroneous readings. It's best to use a case lcd thermometer with the lead directly next to (not touching, but almost) the CPU core. You'll get the most accurate readings this way.

The fan adapters are quite useful. http://www.frozencpu.com for everything case & cooling related. I switched the cheap 60mm fan on my athlon, to a vantec 80mm tornado. It's insanely loud, but I did have a significant temperature drop.

The colder your CPU is, the more you can overclock it. Just don't forget to beef up the cooling everywhere else (mobo chipset, video card) if you plan on overclocking, and make sure you have a high quality powersupply. Otherwise, you'll fry your components.

Copper heatsinks are your friend. They conduct heat far better than the aluminum pieces of junk people like to sell. The "heatpipes" that are now the trend actually do seem to have performance benefits. I've played with them for awhile, and wouldn't go back to a normal heatsink.

Lastly from me, if you upgrade your case fans, bite the tiny bullet, suffer the marginal air flow restriction, and invest in some filters. Otherwise you're going to be cleaning your case regularly with an air compressor. Learned my lesson on that one...

eagl · « **Reply #2 on:** November 10, 2004, 03:04:20 PM »

Underpressurizing your system with extra exhaust fans can lead to dust problems. You'll be sucking air in through every little opening in the computer including cdrom and floppy drives, etc. That means you'll get dust buildups everywhere air gets sucked into the case and that may kill things like your cdrom or floppy drive.

If you use filters on your intake fans and then overpressurize the system, you're blowing filtered air OUT of those openings instead of sucking dirty air in. It's still important to use exhaust fans correctly placed to allow air to flow past hot components and make sure you're exhausting hot air and not letting all the cool intake air just escape through little openings while the hot air stagnates near the cpu and video card however. Using a temperature probe taped to various places in your case can help you identify hot spots and then you can adjust the airflow by moving cables and wiring, adding or subtracting intake or exhaust fans, or even adding in some airflow deflectors and ducting to help the air move smoothly past hot components and out the exhausts.

The problem with overpressurizing the system is that sometimes it leads to areas of stagnant air more often than underpressurizing. If you underpressurize, you get cool air entering the case from all around the system, and that can help prevent hot spots from developing. That's good for cooling, bad for dust buildup. A good, deliberately planned airflow path can get you the best benefits of both approaches.

One tip - most case fan cutouts leave a lot of sheetmetal in the airflow. This disrupts airflow and causes noise. Use a dremel and remove the entire cutout area, then put on a standard wire fan guard. Some people have reported significant noise and temperature reductions with only this simple modification. Make sure you only do this to a completely empty case however since metal particles will kill your computer. Either take care of this during an intial build, or you'll have to completely gut and reassemble your computer to get it done. Or use plastic bags and lots of tape to mask everything off, and take your chances.

Don't assume you got it right the first time... Experiment a bit and see what works. Unless you're doing a lot of overclocking, you should be able to get a reasonably cool case without it sounding like a jet turbine.

Roscoroo · « **Reply #3 on:** November 10, 2004, 11:05:55 PM »

Dremel .. hell ,I just take the offending over heating case to work and either hole saw it , or drag out the plasma cutter and hack away

For air cooled a think air flow thru the case alittle more towards the pressure side is better then trying to vacumn/suck it out .

Ive tried bolth ways and this is what ive figured out that works best .(the cpu temp is 1-2 C lower )

the biggist mistack i see is 90% of all side panel case fans are mounted backwards and they are trying to suck the air off of the cpu fan .
this is a no no . they should be blowing directly on it and helping it out with fresh outside case air . Another trick is if your overclocking heavy on air cooling is to stack anouther fan on either the side or front case fan (just beshure it clears everything )

the lower front of the case is also a intake area and when it sits on the carpeted floor it gets restricted .(toss a board under it at least)

SilverFox · « **Reply #4 on:** November 11, 2004, 07:37:52 AM »

Here's a cheap experiment. Go to the auto section at your local superstore and buy a $1.50 stick on thermometer. Put it in the bottom of your case and close the box. After an hour of AH pull off the cover and note the ambient temp inside your box. If your system is well ventilated, you should see temps below 90°F. As a baseline, mine runs about 80°F.

Actually, Its important to bring cooler air across the CPU heat sink. The pressurized approach will not do this, since it keeps more air in the machine than it sends out.

Water cooling isn't for everyone, but its a viable alternative to pure air. The temps I noted in the first post were from a water cooled machine. Water is pumped through a radiator and across a heat sink on the CPU, Chipset, Video card and Hard Drive. Air cooled temps run significantly higher and that's where the problem lies.

Heat will transfer to the cooler medium. We all know how a heat sink works. However, the ambient temperature effects the efficientcy of the heat sink. The cooler the air flowing across the heat sink, the faster the heat sink will dissipate heat. Cooler air has to come in from outside the box. But according to the manufacturer info, the path the air takes through the box is also important. Both Intel and AMD (I'm not biased

) suggest air circulation strategies in their white papers. The links I provided on the first post offer some professional insight to system cooling requirements. A better understanding of the problem might lead to some innovative ways of thinking.

Ghosth · « **Reply #5 on:** November 11, 2004, 08:15:52 AM »

I cheated.

I had heat issues, tried replacing fans, reversing flow, all kinds of fun stuff.

Ended up with the side of the case off, a 8" fan blowing air in right at the cpu/video card.

It ain't purty but it works.

(If I need more cooling I just open the window behind my box a smidge.)

StarOfAfrica2 · « **Reply #6 on:** November 11, 2004, 02:14:05 PM »

I added a copper heatsink and a high rpm fan to my XP 2600+. Have an intake fan on the front bottom of the case and a home-made piece of plastic cut from a curved vacuum cleaner part that directs the air up toward the CPU. Then I have an exhaust fan pulling the air out just above the CPU. Right now while I'm in-game I run about 40C degrees at the processor. If it gets up to 48C a beeper goes off and warns me so I can shut down.

Roscoroo · « **Reply #7 on:** November 11, 2004, 03:06:05 PM »

thats were mines running 2500+ M barton on air oced @ 2.2ghz
39-41c at idle .. 46c gaming (its 70-75 deg F in the house)

indy007 · « **Reply #8 on:** November 11, 2004, 03:26:30 PM »

Quote

Originally posted by Ghosth
I cheated.

I had heat issues, tried replacing fans, reversing flow, all kinds of fun stuff.

Ended up with the side of the case off, a 8" fan blowing air in right at the cpu/video card.

It ain't purty but it works.

(If I need more cooling I just open the window behind my box a smidge.)

One of the most clever setups I've ever seen was a case made out of what looked like 2" sch 40 pvc, and metal straps that the drives were bolted to. The entire side panel of it was actually a normal, walmart bought box fan. He had pretty good temps

And my PC fans are entirely too loud as it is to take my side panel off

I have to turn it off before I go to bed.

edit -> Oh yeah, I pull 36 degrees idle, 39 gaming.

SilverFox · « **Reply #9 on:** November 12, 2004, 07:49:08 AM »

Some pretty good ideas here that I havn't seen before. I appreciate everyone keeping this light hearted and open. Ideas
come easier that way.

Here's a crazy idea I've got working in my head, the wife confirmed it when she felt my forehead

Clip the tube between the reservoir and the radiator and run the two ends through a gromet in the front of the case then fix a copper tube shaped to protrude down into a beaker. Ice water or dry ice or anything cold that fits can be placed into the beaker during a game session thus cooling the water down even further. If I can keep the condensation down, I think it will work. I'm pursuing the mythical 10°C mark.

If it condenses, maybe she'll let me buy a new system...

I was researching cooling materials on the internet and found these packs that are cold but absorb water and maintain a constant humidity. Better than dry ice they claim. Can't find the link. But I'm gonna put one in the bottom of my kids machine and see if it makes a diff.

boxboy28 · « **Reply #10 on:** November 12, 2004, 09:05:16 AM »

Great idea's guys!

After all my OC'ing and temp related research the general idea that i picked up is that the air flow in should equal air flow out!
air flow is rated in CFM cubic foot per minute(i think thats what its called) but in my case, the case i have has 6 case fans,
2 in front and 1 on the side all blowing into the case!
2 in back and 1 on top all blowing out of the case!

All these are set on 1 speed controller so i can adjust the CFM flowing thru the case.

As well i picked up one of the SLK's 947U Big copper heat sink and a 90mm tornado heat sink fan on a separate speed controller! Yes it can get loud at full speed but i keep it set at low unless its unusually hot inthe room!

My idle temps on the CPU are 36 degrees and max ive seen is like 40 degrees.

Mind you this is a AMDXP2500 OCed to 2.3 G:aok

indy007 · « **Reply #11 on:** November 12, 2004, 09:50:01 AM »

Quote

Originally posted by SilverFox
Some pretty good ideas here that I havn't seen before. I appreciate everyone keeping this light hearted and open. Ideas
come easier that way.

Here's a crazy idea I've got working in my head, the wife confirmed it when she felt my forehead Clip the tube between the reservoir and the radiator and run the two ends through a gromet in the front of the case then fix a copper tube shaped to protrude down into a beaker. Ice water or dry ice or anything cold that fits can be placed into the beaker during a game session thus cooling the water down even further. If I can keep the condensation down, I think it will work. I'm pursuing the mythical 10°C mark. If it condenses, maybe she'll let me buy a new system...

I was researching cooling materials on the internet and found these packs that are cold but absorb water and maintain a constant humidity. Better than dry ice they claim. Can't find the link. But I'm gonna put one in the bottom of my kids machine and see if it makes a diff.

I played with a chiller setup before, using an igloo cooler as the reservoir itself. Drilled 2 small holes in the side cooler, fed down the lines, sealed it with silicone, and dumped in ice when I started gaming. Was a bit more hastle than they're worth, and the results weren't spectacular. Then I realised to move my PC, I had to strap the cooler to it, so I dismantled the setup. Since the cooler was outside the PC, and the tubing was insulated with neoprene sleeves, condensation never posed a problem (and it's usually 90%+ humidity here). I also heavily insulated under the CPU, and on the back of the motherboard with more neoprene.

I'm about to order one of those Zalman fanless watercooler setups. Alittle pricey, not convenient to move at all either, but I'm trying to get my case noise to the obsolute minimum. I think to bring it in line with more effective, active radiator setups, I want to use a peltier chiller.

For those that don't know what they are, Peltier Coolers (or Thermal Electric Coolers, TECs for short), are small, very thin wafers. When you apply a DC current to them, one side becomes very very hot, one side becomes very very cold. The colder you keep the hot side, the colder the cold side becomes. They also need a seperate power supply under almost all circumstances. I know of more than one person that fried their PC power supply, and damaged their CPU, trying to run a TEC off the main psu.

So ideally, I'm going to mill out a copper block, and tap out an inlet & outlet for the tubing. Next, mount a trio of relatively low wattage peltiers (120w probably) to the block. Then put another copper plate over them to sandwitch them down. That will let me mount at least 2 normal cpu heatsinks & fans to it, so the peltier hot sides don't have thermal runaway on me. Probably will use Coolermaster Aero 7+ heatsink + fan combos. Turned down to 21db each, they're be alot quieter than the 55.1db fan I'm running now... plus they look awesome

Hopefully this jury rigged setup can drop my water temps by about 10 degrees. If I can get that much, I'll be really happy

llama · « **Reply #12 on:** November 12, 2004, 12:12:37 PM »

This statement always annoys me:

"So my main point is this. Keeping the system cool will boost performance. "

Sigh.

The correct statement is:

"Keeping the system within is manufacturer-specified operational temperatures will allow it to perform as it was designed and intended."

Example: If a CPU has a rating of, say, 3 GHz and a Max temperatuire of 70 degrees C under load, and it is actually running at 55 degrees C under load in your system, IT WILL NOT BE FASTER IF YOU COOL THE CPU TO 50 or 45 degrees C.

On the other hand, if due to a cooling malfunction, or dust build-up, or exceedingly poor ventilation, this example CPU is running at 75 degrees C, then making it cooler would boost performance. BUT ONLY BECUASE SOMETHING WAS KEEPING IT OUT OF THE MANUFACTURER-SPECIFIED TEMP. RANGE IN THE FIRST PLACE.

Keeping a system cooler than it would otherwise be at the specified operations level allows a tweaker to overclock, sometimes a little, and sometimes a lot. That's where exess cooling is important.

Heat DOES relate to crashes and system stability too, BUT, if your system has a "system temp" of 45 degreex C and it runs stable 100% of the time (within the realm of anything running Windows being 100% stable), getting the system temp down to 40 degrees will NOT make it "more stable." How can something be more stable than 100%?

It may allow you to overclock things like memory timing and system bus speed.

I know a lot of people who worry about system temps for no good reason: they aren't overclocking, their systems are running great, etc, yet they'll ask me what CPU cooler's I'd recommend to get the CPU cooler than the stock unit? WHY? WHY? WHY?

If you're looking for a hobby and like the intellectual challange of lowering temps of computer components (and I do at times too), well, that's one thing, but to blindly believe that "... Keeping the system cool will boost performance...", well, then I have a bridge to sell you might be interested in too.

If you thing the overclocking community is interested about cooling, then head on over to the SFF community (http://www.sfftech.com/ is a good portal for this) and check out their issues. They have the same hardware everyone else is running in a case with a third the volume, and generally low-speed fans to keep things quiet. They know that a CPU running at 55 under load where the max-spec is 70 is fine, even though guys with full-size cases are worring about how to get that same CPU to run at 40 with a veritable hurricane of airflow and cooling.

Anyway, I've vented my speen. I'll duck now. ;-)

-Llama

indy007 · « **Reply #13 on:** November 12, 2004, 12:54:16 PM »

Can't flame that Llama, ur 100% correct.

When I build a new PC for myself, I check what temp it currently runs & what temp it's supposed to run. I use it as a reference point for overclocking. I throw higher flowing fans at it, or in some cases water, get the temps down a bunch, then start overclocking. I don't stop until I have stability issues, or I reach the original temperature

SilverFox · « **Reply #14 on:** November 12, 2004, 03:08:12 PM »

But there is no lower bound to the operating temperatures, only nominal and "do not exceed" bounds. The fact is, cooling down the electronics enhances performance by limiting the minor changes in capacitance and resistance in the circuitry. Simply put, lower temp translates to better efficiency. As a conductive material rises in temperature its capacitance and resistance increase beyond design specification. A constant temperature in the system would be a good thing if its under high limit specfication.

Llama has many good points. Sorry I annoyed you sir.

So I'm not a computer columnist, but I was cooling down infrared sensors with pure helium gas to achieve 25° K (thats Kelvin) temps in 1980. By then I had 7 years behind me of repairing computers at the discreet component level in extreme operating conditions. When it comes to computers and electronics I'm pretty comfortable with what I say, but in the interest of proving my point, I'll do some bench marking with the only varaition being system temp from the case readout. I'll run it at the coolest temp I can get and then run the same benchmark after letting the system heat up with some fans turned off but still well within the manufacturer specs.

I'll post the numbers regardless of outcome.