Lathing, Sanding, Smoothing...CPU

[Exempt]

Holy crap! I just came across this thread, and realized I started it back in 2004 ! lol amazing!

 

[ppe1700]

Holy crap! I just came across this thread, and realized I started it back in 2004 ! lol amazing!

2003 i was a "wee nipper" back then

 

[ladyybugg]

It's all still useful though!

 

[jazon1]

Nice writeup Exempt. From my experience though, lapping a processor's IHS in a straight line in a single direction (and then turning the processor 90° after every 10 or so passes) yields slightly better results than lapping in a circular motion.

Lapping in a circular motion actually makes the IHS on the processor slightly convex in shape. For me, this was really noticeable when applying thermal compound to the IHS. I found it virtually impossible to apply a thin and even layer of AS3 because the edges of the IHS were actually lower than its centre.

After re-lapping the chip in a single direction and rotating it every...ect (you get the picture), I not only found it much easier to apply thermal compound, I noticed about a 1 - 2°c drop in my load temp.

i was once a machinist and used to have to lap parts for the military, actually what works even better than circles or straight lines for movement is figure 8's and dont press down hard at all just use the weight of your hand

 

[CompuTamer]

Lol, the i7 IDLES higher than that chip ran under load. I lapped both my HS and IHS during December, and got close to a 10c drop in temps.

 

[hokiealumnus]

Just had to post this link, courtesy of Inteller at TRP: How to Destroy Your CPU by Lapping It. Look out folks...if you lap, you're an idiot!

 

[jazon1]

Just had to post this link, courtesy of Inteller at TRP: How to Destroy Your CPU by Lapping It. Look out folks...if you lap, you're an idiot!

the guy who wrote that was a moron,did he really think people didnt know they were voiding there warranty?that being said,i have never tried lapping my cpu but i have had to lap a heatsink as it wasn't flat when i got it.

 

[A. Waheed]

That's so nice !!

 

[SighGuy]

3M has .3 micron lapping film what would happen if you use that.

 

[King107s]

Can't belive this thread is still going

3M has .3 micron lapping film what would happen if you use that.

Getting down to finer grit levels only improves the polish and has a neglible effect on the thermal transfer. Getting it flat is the goal here people!

 

[Airbornederekc]

Ya talk about digging up posts from the grave.

I recently lapped my ES 980x but i used a much different set of sand paper.

i started with 600 grit, then moved to 800, 1000, 1500, and finally 2000.

2000 grit is more for show than actual performance, but if your gonna lap why not.


Also Hal is a moron. People do not lap to remove the extra metal for temp drops, rather to make a perfectly flat surface which is proven to transfer heat better. People do it for that extra 5 to 15 degree drop in temps which can get them another 400 or 500Mhz on an overclock, which can put them over their goal and make their ePeen bigger.

 

[Archer0915]

Technically speaking if you could get the surfaces perfectly flat down to the atomic level nothing would be needed not even a clamp if the HSF were sitting on the cpu and the MB were in a flat position as opposed to vertical. Oh also lifting up on the HSF would be bad.

Just thought I would throw that in.

 

[Leegit]

Lapping improves temperatures because it reduces the thermal resistance. The whole process is analogous to electricity.

Thermal Potential = Voltage Potential
Thermal Resistance = Electrical Resistance
Heat Transfer = Charge Transfer

So it's not just smoothing the surface but also the removal of material with higher thermal resistance that helps lower your temperatures.

IMO, the surface is concave not because of the thermal expansion of the material, as expansion in the Z-axis in general is lower that X-Y. More likely it because the chips have higher warpage on the sides/corners after fabrication (Source: IPC) and to increase producibility (yield), they have to mechanically load the sides/corners less.

Also, its really important to have some quality control and avoid leaving any residue on the surface during and after the process. Even when they fabricate PCBs at our plant and bake them in the oven to remove the moisture (after cleaning) for 10+ hours, there is always a thin film of water that remains. I would avoid using any water on the surface. Just using IPA + cotton swabs will leave micro-fibers on the finished surface.

That said, I do think there are gains to be had but I wouldn't try it until after the warranty has expired.