nF2 chipset lapping - how far?

[trodas]

I figured out I better ask twice (to be sorry once) before I start.

I have one old DFI LP2 board and it is unstable in the long run (15h of folding and crash)... I noticed how bad the NB chipset contact with cooler on is (almost hole in the middle of the plastic on chipset!) and going to lap it. How far I can go?

I read sometimes as far, as I see the cooper?
True?

http://www.slibe.com/imagestumb/188c18cd-nf2_chipset_temp.jpg (http://www.slibe.com/publicimage/188c18cd-nf2_chipset_temp/)
(the nF2 chipset has no visible metallic part ATM, DFI NF2 mobo)


Even w/o the lapping it can score fairy high O/C, so I wonder how I can take it with the lapp :D


edit: find some pics like in this guide: http://www.techarp.com/showarticle.aspx?artno=70&pgno=0
But looks like they just flatten out the surface? I would like get most of the temperature-resistant PVC out of way, so, what is why I asking how deep can I go. Till the little holes near corner disappear? Till I see cooper?

[trodas]

SAE: "there must be a spreader, t would be nonsense not to integrate one, good luck, mate^^"

So, the lapping experiment is done, mobo still works, and I gained some knowledge. First and worsest of all, there is NO heatspreader inside of the nForce2 chip in these later revisions with completely plastic chip - unbeliably as it sounds, but true for the nForce2 SSP Ultra 400 in my case.
Let pictures speak for themselves:

http://www.slibe.com/fullimage/97b915fc-nForce2_lapping_.jpg (http://www.slibe.com)

http://www.slibe.com/fullimage/d0539121-nForce2_lapping_.jpg (http://www.slibe.com)

Unfortunately nVidia showed me again what I would call "nonsense" at best.

Testing lapping (pictured) was on JetWay N2PAP Ultra. I dubt the mobo will work, but it was dead one for sure before, so... (two caps in the Vdimm powering explode and took the mosfet with them...)

The chip thickness (measured over the green bottom) is exactly 1.25 mm.
When I reach 0.475 mm the resistor at one end and then these wires begin to surface - so, I lapped my DFI LP B nForce2 core to 0.50 mm and I hope for highly increased overclocking of the chipset :D

When I get there a good heatsink, we see ;)