Poor Q6600 & U120-E lapping results

Y

yangp1127

Weaksauce
Joined
Nov 9, 2007
Messages
68
Guys, i've lapped my U120-E & Q6600's IHS ...with 150, 400, 800 grits of sand paper...for the CPU i did dry sanding....
at 3.2ghz, 356x9, 1.375v....used zalman's STG1 thermal grease, which i followed the manufacturer's instruction of putting a coat on HS & another on CPU.....my idle temp is like 47, 49, 43, 43.....under prime95, large FFT max heat test, it goes up to 63 63 58 58..... it used to be like 67 67 59 59.... why's my idle temp & load still so high ? the room temp is around 70F...no higher... should i have gone higher than 800 and used 1000-2000 grits to finish it off ?? i mean i saw in the sticky guide people using 1000-2000 grits.... i just forgot to pick those up during my trip to walmart... :-/ could it be the reason why the temp was still so high ?
 
your IHS was definately uneven, a 5C drop on one core and only 1C on the other is quite weird, but people only use higher grit for a mirror finish, that is all
 
i lapped till the nickle plating came off and the copper came thru...there were no uneven silver nickle plating left on my cpu tho.. :/
 
Yea, When I lapped my processor, I went from 130 to 400 to 1000 to 1500 and finished with 2000 Grit sandpaper.

I also wouldn't follow those thermal paste instructions.
A cooked grain of white rice sized dot in the middle of the CPU is all that is needed.

You can also lap the heatsink base as well.
 
ahh...i think i'm gonna have to relap both....& reapply the thermal paste... :/ thx for the help!....
 
Did you check to see if it needed lapping before doing so?

What did you do to make sure you lapped if flat?

The benefit of lapping comes from making a non-flat cpu heatspreader.... flat. It's really not about making it shiney.

If it was concave before, there should be a benefit.

Then again, it's also possible that your heatsink was slightly convex originally to help with concave cpu heatspreaders.
 
The finer the grit you finish with, the flatter your base will be. I won't make any guarantees, but there's a chance you'll get the results you're looking for if you go back to it with some finer sandpaper.
 
cool thanks, when the breaks over, i'll test it out.. is it possible that i might sand it down too much on the IHS of the q6600 tho? thats my fear hehe
 
Zero82z said:
The finer the grit you finish with, the flatter your base will be. I won't make any guarantees, but there's a chance you'll get the results you're looking for if you go back to it with some finer sandpaper.
Click to expand...

No - flat has more to do with the surface being used to lap against and the technique used.

The grit itself has absolutely nothing to do with achieving flatness.

A finer finishing grit will achieve a shinier surface.

However... shiny is not the goal - flatness is.
 
markintosh13 said:
No - flat has more to do with the surface being used to lap against and the technique used.

The grit itself has absolutely nothing to do with achieving flatness.

A finer finishing grit will achieve a shinier surface.

However... shiny is not the goal - flatness is.
Click to expand...

Flatness and shininess are directly related. When a surface becomes flat, it reflects all light rays at the same angle, resulting in a perfect reflection. Generally flatness isn't the main concern with lapping because some people use polishing compounds to achieve the shininess. Now, this actually does make the base flatter, but the compound is not nearly as thermally conductive as the metal the base is made from or the thermal paste used, so it actually makes temps worse. However, lapping with a finer grit makes the surface naturally flatter, and therefore not only makes the base more reflective, but also improves contact between the CPU and heatsink and will reduce both the temperature and the amount of thermal paste needed, since contact between the heatsink and CPU will be better to begin with.
 
Shiny and flat are not synonymous - Why could you not have a shiny sphere?

I agree with mark - most importantly you're trying to make it flat. Yes, there is also an advantage in the fact that the surface is made smoother (or shinier if you want to call it that), but there's no point in having smooth surfaces if they're not flat against each other.
 
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