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Replacing a CPU fan/ heatsink

Hi guys and girls,

I'm about to replace my Intel stock cooler for something a bit more adequate, because when the machine is under a heavy processing load, the fan gets so loud (~4000RPM) that it sounds like it is about to lift off! This is due in no small part to the massive amount of heat given off by my 6600gt GeForce GPU. Whoever designed the ATX form factor clearly stayed in bed the day of his thermodynamics lecture in college, as it is plain to see that if you put a hot component under another hot component, the top hot component will absorb the heat from the one below it and heat up even more.  

I have bought (or more accurately, paid a deposit for ) this cooler:

http://www.coolermaster.com/index.php?LT=english&Language_s=2&url_place=product&p_serial=ICB-V83&other_title=+ICB-V83+JET%204

The CoolerMaster jet 4 if the link doesnt work and you have to google it.

Basically my question is this: my machine came with a fan which employed thermal paste on the processor die to transfer heat - do I NEED to remove this prior to the installation of my new cooler or can I just spread a thin new layer. I have read conflicting suggestions saying 'Don't bother removing it' or 'Use 90% isopropyl alcohol.' I'd like to steer clear of putting aggressive chemicals on a  €200 + processor if I can.

Any suggestions would be much appreciated

Rgds

Pushpop
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Callandor
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You should remove the old paste, because you want to get as much metal-to-metal conduction for heat transfer.  The small amount of new paste you add is only to displace any tiny air gaps, which don't transfer heat well at all.  Rubbing alcohol which you can get from the drug store is not what I would call an aggressive chemical, ad is sufficient to remove old paste.  Spread the new paste with a plastic card edge as thin as you can.  When you mount the heatsink, make sure it sits flush against the cpu, and give it a slight twisting motion to spread the new paste more.
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nltech

yes! clean off the cpu. the 'old' and 'new' compounds may be chemically incompatible with each other.   keep in mind that newer cpu's employ an integrated heat spreader and don't have a naked core (like the early socket 462 athlons); either way, a little isopropyl won't hurt anything. just be careful with the pins and static when handling the cpu.

a 'high purity' isopropyl alcohol (i special order 99% just for this task) and some high quality q-tips does wonders.  don't overly saturate the swab, and watch to make sure you don't leave any lint behind.

if you plan on replacing the stock compound on the new heat sink, scrape it all off with a plastic putty knife and follow the instructions for the compound you're using. see http://www.arcticsilver.com/instructions.htm for arctic silver products.
First, as noted above, you absolutely want to clean off the old compound.  Carefully scrape the top of the CPU with a credit card; then use a clean cloth (or Q-Tips as suggested above) with a bit of isopropyl alcohol (rubbing alcohol is fine -- doesn't hurt to use "high purity" as suggested; but it's really not necessary -- you just need to wait a few more minutes for the drying process with a normal rubbing alcohol compound).

The heatsink you've selected isn't bad ==> but this is much better:
http://www.newegg.com/Product/Product.asp?Item=N82E16835118223

Note that the Coolermaster has a thermal resistance of (at best) 0.35 °C/W.   This means for every watt of energy that it dissipates, the temperature will rise 0.35 °C.

... the Zalman 9500's thermal resistance is between 0.12 °C/W and 0.16 °C/W, depending on the fan speed => so at the lowest fan speed (virtually silent) it still has less than 1/2 of the thermal resistance of the Coolermaster.

Note:  I'm not a big fan of decorative LED's, but the Zalman 9500 without the LED's is only shipped with mounting brackets for Socket 775.   The LED version (that I linked to above) includes mounting hardware for Socket 478 processors.
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mwnnj
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Agree the best thermal compound to use is Artic Silver 5 -- but do NOT apply it as suggested above ("... really tiny film ... over the CPU's surface ...").   Follow the detailed instructions on Artic Silver's site (very small BB-size application in the center of the CPU => the weight of the heatsink and the thermal dispersal over the first few hours of use will disperse the compound and fill in all of the microscopic gaps in the CPU and/or heatsink).   Details here:  http://www.arcticsilver.com/arctic_silver_instructions.htm  (note Item #9 about 2/3rds of the way down the page).
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ASKER

All,

Thanks for all your comments so far. I suppose my case is leaning towards positive pressure, as i have case fans blowing air into the case through the front panel and side window, which is then extracted by my PSU fan. I had a look at the Zalman cooler, but it's incompatible with my motherboard. The problem is a mixture of a black case, minimal clearance at the back of computer (3-4 inches ) which I cant do much about. a noisy CPU fan, and a scorching GPU.
Just im terrified I'll damage my processor. Being a student, the money to buy a new one doesn't come along too frequently! :-)
Measure carefully -- the Zalman 9500 actually fits in a lot of cases where a 7000 series won't.
You might consider adding a exhust fan at the rear of the case to improve air flow
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ASKER

Well, I didn't do any measurements as such! The Zalman website has a list of motherboards which are incompatible with the 9500, and mine is one of them :-<
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ASKER

I have three fans at the rear, one of which is the PSU fan. The other two blow air into the case, which  im not sure is such a good thing
The ones at the rear will do a better job of moving air if they blow out . .
All of the rear fans should absolutely be blowing air OUT of the case !!
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ASKER

Yes I concur. However, they have been screwed in by the OEM very hard indeed, making it difficult to remove them. I wish there was some way to reverse them
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ASKER

By the way, i took a picture of the inside of my machine for better insight:

http://www.redbrick.dcu.ie/~pushpop/pc-guts.jpg
Once you get the two rear fans turned around so that they blow out, you may want to put one up front to help pull air in
"... Zalman website has a list of motherboards which are incompatible with the 9500, and mine is one of them ..." ==>  Note that the list on Zalman's site shows two things:  (a)  boards that are "compatible" -- meaning the heatsink fits entirely over the board; and (b)  boards that the heatsink will extend beyond the edge of -- meaning you need to have the amount of space shown on Zalman's site between the top edge of the motherboard and the power supply.

The fact your board isn't listed as "compatible" doesn't mean the 9500 won't work -- it simply means it depends on the case it's installed in (i.e. whether or not you have the specified amount of additional space).   Like I said earlier -- you should measure.   The picture you posted above shows what looks like perhaps 1/2 inch (= more than 12 mm) of space between the board and the power supply.   You should measure it -- but it sure looks like the 9500 would easily fit.

==> but you definitely need to get those rear fans mounted correctly !!  Fan screws can be tight; but there's only 4 of them -- just have patience and unscrew them a little bit at a time !!
you may even find that reversing the airflow of those case fans (to blow out) will make enough of an improvement that the cpu heatsink/fan upgrade is less critical or even unnecessary.
Agree -- it will certainly improve the airflow, and that will almost certainly help the CPU temps.
that's right,perhaps it's also needed that the cpu's heatsink ,should be cleaned out of dust bunnies,i can see this well from your picture,so
in regarding this issue ,check out also this guide:
http://www.short-media.com/review.php?r=122
also make sure those cables on the front should be reasonable sorted(not trying to say something personal!excuse),cuz there is a mess in the front part of your case and it's definitely disturbing the right way of the airflow in the PC,check out for such 'tools':
http://cableorganizer.com/cable-ties/

cu