lapping

[zif33rs]

Short answer=NO

It will not even the core temps. A few degrees difference is nominal between cores.

Lapping will only flaten the surfaces of the heatsink and cpu IHS. Lapping to a mirror finish does more harm than good. if you want flatness, be sure to at least leave the surfaces a tiny bit dull. This will help in the bonding of the heatsink and cpu with the thermal grease, thus ensuring better heat transfer.

results may vary.

ive seen a 3c average drop in temps..both cores and cpu. the delta between cores has dropped to 3c-5c now.

could not be happier was alot of fun too!

 

[1Time]

results may vary.

ive seen a 3c average drop in temps..both cores and cpu. the delta between cores has dropped to 3c-5c now.

could not be happier was alot of fun too!

Have you posted this in support of lapping a heatsink flat and to a shiny finish (instead of dull)?

 

[zif33rs]

no...cant seem to post there...might be my "newbness"

 

[1Time]

no...cant seem to post there...might be my "newbness"

I asked because I'm trying to understand the point of your previous post with the screen shots.

 

[OldSkool]

I asked because I'm trying to understand the point of your previous post with the screen shots.

Rule #1 Never lap and not post pics

 

[1Time]

Rule #1 Never lap and not post pics

Pics are good. An explanation of them would help.

 

[OldSkool]

Pics are good. An explanation of them would help.

Ah I see. Like which pic represents which grit, I gotcha now.

 

[zif33rs]

yea..i had a hard time laying out the pics...finally just gave up and thats what i got...sorry about that...

the first series of pics(and the 2nd as well) are reversed in order. basically going from disassembly and then to the first stages of lapping. started out with p400 grit and then 600. the first two images are when i stopped at 600 and moved to 800. then 2nd post is going from 800 to 1000....then about 10 minutes each at 1500.

 

[1Time]

Ah I see. Like which pic represents which grit, I gotcha now.

Yes, if that's what needs to be explained in a particular pic.

 

[1Time]

yea..i had a hard time laying out the pics...finally just gave up and thats what i got...sorry about that...

No problem. Off hand I'm not aware of a correct way to post pics. However, here's how I do it, if that helps. Upload and resize the photos to photobucket.com. Copy the IMG Code by clicking on it. Past it to a message dialog box like when you're getting ready to post. And then type an explanation above it like this:

Here's a pic of an air duct I made recently from modeling cement, clear packaging tape, and parts of CD and cassette cases.
(IMG Code pasted here)

And here's what this looks like after I do it.

Here's a pic of an air duct I made recently from modeling cement, clear packaging tape, and parts of CD and cassette cases.

 

[1Time]

Some on topic pics.

This pic is of 1000 grit wet/dry sandpaper taped to a bathroom mirror. I rinsed / wiped the sandpaper with a wet sponge before pulling the heatsink from top to bottom 3 or 4 times and then rinsed / wiped it again with the sponge. Edit: I used 400 grit wet/dry sandpaper before using the 1000 grit to flatten the heatsink.



This pic shows a stock aluminum A64 heatsink after lapping. Flat in the middle, edges a little rounded, and tiny scratches from sanding.

 

[1Time]

After checking for flatness with a straight edge, I found it wasn't. I should have checked it the first time after sanding with the 400 grit. I sanded again with 400 and 1000 grit and here's what it looks like now. It looks slightly shinier than before but still a dull finish.

 

[bldegle2]

1Time,

Nice shots of the lapping.

As far as the rounded corners/edges go, that is an indication your sand paper is not truly flat or the paper is a bit loose, as the sandpaper gets wet, it can 'ridge up' a bit on the leading edge when actually performing the lapping sequence, thus leaving the rounded edges as shown with your pics.

it probably will not adversely affect temps, just pointing it out to you.

when I lap, I spend maybe 5 minutes or less and I am done, I stop @400 grit....most of the time, the CPU's are a bit concave, I found that all you have to do is barely take the edges down and you reach flat, did the same for my waterblock...on my opty 165 you can see a small amount copper at the edges, but the center is still silver colored and you can just make out the stepping and codes dates we all cherish so much when figuring out which slugs are the best....

anyway, back on subject, I stopped because my straigthedge indicated FLAT, flat contact, whether the surfaces are shiney or dull will give you the BEST heat transfer with proper application of thermal paste.

i commend those who go to all the way to mirror finish, it does look nice, whether the added effort is worth it is up to the user...

laterzzzz................

 

[1Time]

1Time,

Nice shots of the lapping.

As far as the rounded corners/edges go, that is an indication your sand paper is not truly flat or the paper is a bit loose, as the sandpaper gets wet, it can 'ridge up' a bit on the leading edge when actually performing the lapping sequence, thus leaving the rounded edges as shown with your pics.

it probably will not adversely affect temps, just pointing it out to you.

Thanks, and I was aware of that, but very good pointing that out for others too. As you know, the processor only contacts the flat center so the rounded edges don't affect cooling.

anyway, back on subject, I stopped because my straigthedge indicated FLAT, flat contact, whether the surfaces are shiney or dull will give you the BEST heat transfer with proper application of thermal paste.

I agree. I don't think there's a significant difference in cooling between a shiny or dull finish. The best cooling is with two flat surfaces and a proper application of a TIM. Now you've got me wanting to lap my processor... lol.

 

[baditude_df]

Yes, I do believe that the edges of my processor became a tad rounded on my first attempt. Not really enough for the razor blade to show, but the dye test brought it out a bit. Good chance it's just an optical illusion though, it's Very hard to capture something that slight with a camera.

Here's the post lapping dye test pic:

Keep in mind, there is excess dye around the edges of the processor from bleedover that give the illusion that the edges are rounded, but if you look closely, you can see the slightly darker color leading into that bleedover.
Regardless, much better than it was before.

 

[1Time]

Yes, it's definitely not best to have rounded edges on a processor. So you've gone beyond using a straight edge to determine flatness. Hard to imagine that making a noticeable, meaningful, or measurable difference, but it does look very nice.

 

[1Time]

So I'm interested in anyone's opinion on how much of a difference one should expect between using a straight edge versus a reflection technique like shown above?

Seems to me it should work well enough by holding the HS up to a light, placing a straight edge on it a few different ways, and checking for flatness by looking at the light or absence of it under the straight edge.

And if a reflection technique is better, has anyone an opinion they care to share on about how much better they think it might be? Like 50% better or 500% better?

And then, please anyone opine on this as well. To what extent should use of a reflection technique over a straight edge technique translate into better cooling? Something like 0.01% to 0.1% I'm guessing?

Not looking for a debate or discussion really. Just interested in reading anyone's opinion on this. Thanks

 

[zif33rs]

personally...i think the fluid method looks cool and all...but id worry about the chip "floating" abit on the surface tension. and if you press hard enough to correct that...your possibly bending the chip flat. a good machinest straight edge or a razor is my method.

 

[baditude_df]

personally...i think the fluid method looks cool and all...but id worry about the chip "floating" abit on the surface tension. and if you press hard enough to correct that...your possibly bending the chip flat. a good machinest straight edge or a razor is my method.

How's it gonna float? It's squeezed between two pieces of glass.

And yes, a bright light and a straight razor blade works, but you need very good eyes to see the level of irregularity that you are trying to lap out. A good dye or Ketchup test can and will show irregularity that a razor will not show so well. It is a much better test IMO.

 

[1Time]

So I'm interested in anyone's opinion on how much of a difference one should expect between using a straight edge versus a reflection technique like shown above?

Seems to me it should work well enough by holding the HS up to a light, placing a straight edge on it a few different ways, and checking for flatness by looking at the light or absence of it under the straight edge.

And if a reflection technique is better, has anyone an opinion they care to share on about how much better they think it might be? Like 50% better or 500% better?

And then, please anyone opine on this as well. To what extent should use of a reflection technique over a straight edge technique translate into better cooling? Something like 0.01% to 0.1% I'm guessing?

Not looking for a debate or discussion really. Just interested in reading anyone's opinion on this. Thanks

One correction: the method was referred to before as a "dye test" and not a reflection technique as I called it. Just trying to get a feel for what other think of the differences between using a straight edge versus the dye test. Thanks again to everyone who replies.