CPU Cooler Lapping!

[MartinW 0]

As those of you that frequent the Just Flight Forum will be aware, I have become a little disillusioned with the quality of the Arctic Freezer 7 Pro CPU cooler of late.

I noticed that my Core 2 Duo E6700 was about ten degrees hotter than I was accustomed to, I was pretty sure that it was simply a case of dust accumulation and that a simple spring clean would rectify the problem. In addition, I wanted to try Zalman thermal compound, as I had read that some test reports had concluded that it was better than Arctic Silver 5 when the CPU was under load.

When I inspected the cooler, I noticed that there was indeed a considerable quantity of dust jammed between the fins, the fact that the fins are so close together almost certainly contributes to the coolers tendency to be thermally impaired relatively quickly. I would encourage anyone with this cooler to check his or her CPU temperatures regularly; you may well discover that cleaning is required a little more often than you are accustomed to.

As I was applying the Zalman compound anyway, necessitating the coolers removal, I decided to experiment with lapping the base of the cooler. For those of you not familiar with this technique, it's often dome in an attempt to better the efficiency of the cooler.

Lapping has two main objectives, the removal of deep scratches to the base of the cooler and more importantly, to flatten the base as much as practicable. On removing the cooler and begging to lap, I noticed immediately that the base was concave. A concave base is not good for efficient heat transfer, it results in a larger quantity of thermal compound in the region of the dip and thermal compound is designed to fill minor scratches and imperfections, not large voids between the CPU heat spreader and cooler base.

I continued the lapping process with a fairly course grit paper and copious amounts of water until the concave section of the base was no longer visible and then with progressively finer grades of paper I removed as many of the deep surface scratches as possible. A super mirror like surface is NOT required, it's far more important that the base is as flat as possible to maximise the contact area.

I am still testing the cooler, it will take at least a week before the Zalman paste cures and I can determine if the fruits of my labour were worth the effort. Good practice though for when I fit the Thermalright Ultra 120 Extreme. Not sure if lapping will be required for the Thermalright, usually the base of Thermalright coolers is very flat, although I gather the occasional less than perfect example slips through the net.

If anyone is tempted to lapp there cooler base, please remember that you do so at your own risk, it is possible to remove too much material and render your cooler useless or compromise the efficiency of the cooler below the unmodified thermal efficiency. If in doubt, leave it to the crazy people like me. :eyebrow:

P.S. Don't attempt lapping with out understanding the techniques required and accepting the risk!

[mutley 4,498]

Your just strange :eyebrow:

But thanks for posting, how about I come up and visit and we try to sort out why my PC keeps crashing in the middle of flights!

Cheers

[allardjd 1,853]

Martin,

I'm impressed with your lapping operation, actually. Well founded on good engineering principles and, from

the description, well executed.

Nice work....

John

[MartinW 0]

Thanks John.

Some go crazy and finish with 2000 grit paper, totally unnecessary and can be detrimental. The particles that make up Arctic Silver 5 happen to fit very neatly in the microscopic grooves left behind by 1200 grit paper so anything smaller than this (assuming you are using Arctic Silver) is a waste of time and can decrease thermal efficiency.

It's quite surprising how inefficient some (and not always the cheap ones) coolers can be, with concave bases and very course groves in the surface. It costs time and money I suppose to go the trouble of carefully lapping in the factory.

The first thing I’ll do when I get the Thermalright is to check the base for smoothness, the Thermalrights are usually very good in this respect but we shall see. The next task will be to check the most important factor of all, that the cooler base is flat. Best way to do that is with the edge of a razor pressed against the surface and then the cooler held up to the light.

It has to be said though, that if the base is flat and relatively smooth then lapping is a waste of effort and unlikely to make any difference. Some coolers can be improved considerable though with as much as 1-5 degrees knocked off the load temp.

Your just strange

Yes Mutley, we know that and your bottom smells of... just had a thought, you could lap my cooler with your rough doggy tongue.

I take it you are still having problems with your PC crashing then Mut? Have you fitted your new super powerful PSU and tested your ram?

Does it crash with anything else or just the sim?

Try running Prime 95 stress test to check out the CPU and running the 3D mark 06 tests to stress the GPU.

There are other tests you can run.

I take it you’ve checked all the temps and updated drivers, defragged, registry error checks and all the usual maintenance things

[mutley 4,498]

Hi Martin,

Today I put in my old 6800GT and made a flight from NY to DC so I thought it was the 7900 but whilst still on the ground at Dulles it crashed (rebooted) the same as before.

So I re-installed the 7900GTX and went looking at he event viewer. I had previously disabled the iPod service as I had read elsewhere it could interfere. So I have disabled a couple of other services I only need when working from home and remote desk-topping to work.

So I am now really clutching at straws I have done the mem test and may try the stress tests you mention. I only get problems with flight sims FS9 and X. I don't really use my PC for any other graphic intensive programs.

We will see.

Cheers

[MartinW 0]

If it's just the sim Mutley then it sounds like a software issue rather than hardware.

Although in my experience the sim is almost as demanding as prime 95 for the CPU. The usual response from CPU overheating is throttling back though, not a crash.

I would try a graphically intensive test such as 3D mark and do check those temps, although having said that the usual response from the CPU when it over heats is to throttle back.

I know there is an issue with the ATI drivers and FSX that causes a crash but not with nVidia.

It could be any one of your add-ons at fault, have you got a restore point you could try that would take you back to a point before the issue arose. Then you could install each add-on one at a time, and test each one until you tracked down the culprit.

[mutley 4,498]

Martin.

I think I need at some time to start afresh with all my software but that is what I did last October.

I am going to keep chipping away at it. The flight I had today was so enjoyable as I thought I had found the problem. I really miss decent stress free flights worrying about at what point it is going to crash. So I am going to stop throwing money at it and get to the route cause.

Thanks