Temps, Lapping, AS5, and more! Need Input :)

D

DJS2

Limp Gawd
Joined
Aug 25, 2005
Messages
344
Hey all, so while I wait for my replacement video card (Damn you leadtek...3+ weeks and counting :mad: )... I cant help but mess with my hardware.

So my temps were running a little higher than i wanted them to on watercooling, and im trying to improve my WC and airflow as much as I can before I get my card back so I can OC immediately and not worry about temps. They were around 42-47c not idling but not even close to load.

Decided to remount my WB and wanted everyones opinions.
C2De64001.jpg


DDTDX1.jpg


  • I put the AS5 on kind of sloppy I'll admit, but could that be a reason why my temps were a few degrees higher than norm?
  • Should I lap the cpu or WB? The only real thing I know about lapping is using fine grit sandpaper. I dont really understand how it is more effective though, or the process of it, anyone care to explain? Also, should I consider it?
  • I found one of these laying around that I bought a while back for whatever reason. Worth it to put in on my NB with some AS adhesive?

Thanks all, Im sure ill get some good responses:p
 
The contact definitely doesn't look very good, mounting seems to be a problem. You sure you're putting a small dot in the middle and spreading evenly (center)?

As for that Blue Ice, forget about it and just put a 50mm fan over the nb on your P5B-E.
 
Kuyt said:
The contact definitely doesn't look very good, mounting seems to be a problem. You sure you're putting a small dot in the middle and spreading evenly (center)?

As for that Blue Ice, forget about it and just put a 50mm fan over the nb on your P5B-E.
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Well, not exactly:D Just used an old credit card and tried to spread the AS around the cpu, I knew that it was a slightly sloppy job, im just checking with you guys to see how badly i messed up. When I reapply it I will definately do it the right way.

I can unscrew the fan from the blue ice, would that fan work well? (fan is only 40 x 40 x 15mm). Is this even something I should be concerned about? I never really monitored chipset temps before.

Also, im very curious about the lapping.
 
i kinda did what you did the first time i mounted my heatsink. took a razor and spread it around.

i resunk it using the above method (just putting a tiny line where the actual core is) and my temps dropped a ton. i was idling at like 45, 65 load. now im idling at 30, 52 load.
 
I put the AS5 on kind of sloppy I'll admit, but could that be a reason why my temps were a few degrees higher than norm?
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Yes. And the poor mating.

Should I lap the cpu or WB? The only real thing I know about lapping is using fine grit sandpaper. I dont really understand how it is more effective though, or the process of it, anyone care to explain? Also, should I consider it?
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Both. you ensure both surfaces that go together are flat and mate well for the maxium transfer of heat from the cpu to the HS/waterblock. Google "lapping guide"
Important Lapping points.
1) use only a piece of window pane glass ( get at lowes etc, less than a buck, a 6 x 6 piece is more than enough, steal the glass cover from a picture frame in a pinch)
2) use only wet and dry sandpaper and wet it often while you are lapping.
3) flat is more important than shiny. go until at least the entire mating surface shows effects of lapping with 1200 grit. finer is up to you.
4) write down all info off of the top of the cpu before you destroy it with lapping.
5) its easy as hell.
6) once both parts are lapped, signficantly LESS AS-5 will be needed. Before reinstalling put 1/2 of recommended amount on the parts and press them together and inspect the mating and distribution like you did in your pics (way to much there, btw but with the so so mating probally was a good thing.)
7) my little twist, after done, fold over a piece of the finest grit paper you have, a used piece is ok, making sure its big enough so that the fold is not in the way, wet the hs and the cpu heatspreader and the folded paper well, and putting the paper between the two parts lapp them to each other with small circular motion. Make sure there is nothing between the folded paper (old grit etc).
8) clean everything afterwards, and protect the back of the cpu, handle very very carefully while working.

I found one of these laying around that I bought a while back for whatever reason. Worth it to put in on my NB with some AS adhesive?
Click to expand...

If it will fit, however I would remove the stock one, clean everything, replace the crappy push pins with real screw, washers, lockwashers and nuts and use AS5. Dont crush the motherboard, just snug it down carefully and evenly See if the fan from the blue ice could be used on the stock. .
 
To expound on why lapping improves temps:

When a heatsink (and the CPU IHS for that matter) is manufactured, there are tiny little ridges on its surface. The purpose of TIM (thermal interface material, like AS5) is to fill these gaps and prevent air from being trapped as air is an insulator and prevents efficient heat transfer. However, the thermal conductivity of TIM is not nearly that of the heatsink. If the heatsink and the IHS were both perfectly flat, there would be 100% contact between them. You could eliminate TIM altogether and have maximum heat transfer. However, in reality this will never happen, so the closest you can get is to remove as much of the ridges as possible to maximize contact and reduce the amount of TIM needed. Lapping is how you accomplish this.

The caveat is that lapping isn't needed as much these days as many high-end air heatsinks and most waterblocks are machine finished flatter than you could ever get by hand lapping, so YMMV.
 
No way to tell if you need lapping from those photos, too much old grease in the way.

Lapping is over-rated, in my opinion. You should do it if there's an obvious divot or rough work and you know what you're doing. Far more often, however, it becomes yet another excuse for obcessive types to strive for a mirror finish - even as they round corners or warp a base that then removes significant percentages of total contact area.
 
Well i don;t understand why his contact was bad. As i see the cpu and block had a good contact as you can see the center of the cpu and block has evenly divided AR5 on them.

Specially when you pull the block from CPU the picture will be just like that, no matter how many times you try.

Can any one show me the good contact picture?
 
ive said this before and will say again....no matter what you buy, its not flat! it might have a nice finish and shiny but its not flat. the best way to get good heat transfer is to have a flat surface and less thermal paste. now for pics;)

these are OLD pics with my POS camera so they arent that good but they help

look at the low spot in the middle...
Picture157.jpg


the most important part of the cpu isnt even in contact with the heatsink, its only touching on the outter edges because its lower in the middle
Picture187.jpg


the finished product :D
Picture258.jpg

Picture261.jpg
 
Krayzie, that's some awesome lapping. Could you give a summary of how you lap something that great? What I've seen people do before is:

400 grit sandpaper
600 grit sandpaper
2400 grit sandpaper
In that order.

Do it by laying the sandpaper on a flat surface (example?), getting the sandpaper wet, and then rubbing the heatsink/cpu on the sandpaper.
 
saintnicholas003 said:
Krayzie, that's some awesome lapping. Could you give a summary of how you lap something that great? What I've seen people do before is:

400 grit sandpaper
600 grit sandpaper
2400 grit sandpaper
In that order.

Do it by laying the sandpaper on a flat surface (example?), getting the sandpaper wet, and then rubbing the heatsink/cpu on the sandpaper.
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read the entire thread, the answer you seek is already there. But since you wont, pane of glass, yes, just keep going finer in grit. Get 50micron lapidary faceting plates if you want to get crazy about it. Polish it at the end with brasso etc if you want shiny. Ton of good guides if you google , guess what .... "Lapping Guide"
 
thanks all for ur suggestions and opinions. I would be fine with lapping my WB, but im not so sure about my cpu..

c2dcpu.jpg


c2dcpu1.jpg


WB.jpg


what do u guys think?
 
use some brasso on that block, it looks dirty.

i'd forget about lapping the CPU, it makes it hard to sell, and it's not too much of a difference.

edit:i've used that camera, i really love it.
 
filthysanchez said:
use some brasso on that block, it looks dirty.
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Brasso is completely pointless! you want to get it flat and not shiny. By the time you get to 2000grit, it will be shiny on its own.

another tip: put some soap in your water so it provides some lubrication so your heatsink doesnt get stuck on the paper and use LOTS of water, as much as possible, keep the sand paper clear. ohh, take your time, i know most people give up half way through but once you finish its complely worth it. as for the cpu, just hold it from the edges and lap away. dont worry about it getting wet (i threw mine in a bucket of water and its still working a year later, using it to type this right now) just make sure it is completely dry before you throw it back into your system!
 
what do u guys think?
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Nice more than good enough.

Can please some one show me a picture of the perfect contact?
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http://www.fotolia.com/id/1264195

Originally Posted by Krayzie135
Brasso is completely pointless! you want to get it flat and not shiny. By the time you get to 2000grit, it will be shiny on its own.
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Be advised Brasso is a grinding compound in its own right and much finer than 2000 grit. And while flat is the primary goal, surface roughness (and the type and size of the TIM particles ) is a very valid concern (if you are insane). For fun I do mine on a lapidary fauceting machine with Raytech 1/2 micron diamond dust. When I mate the parts you cant pull em apart, you have to "slide' the cpu off of the block . However it makes little difference in temps, so little I could not measure it compared to stopping at 3000 grit. It does save a ton on AS5, the tiniest bit rubbed into the surface of the block seems to work best. I am insane. For flat you could probally stop at 2000 grit, hell even 1200 once the surface was uniform, and be plently flat enough for a good thermal contact.

However you have a point, polishing without the proper equipment can ruin your work on trying to get the surfaces flat.
 
I think that you might benefit from lapping after seeing this photo:

c2dcpu1.jpg


Kind of looks like you have heavy edge contact impressions in the IHS, which means center contact is minimal. Mine was similar, lapping the IHS and cooling tower resulted in 10C drop in Orthos.
 
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