bad 8600M video on Sager np2092

my Sager np2092 had to be returned under warranty to replace the nvidia 8600M Gt video chip in Jan. It went out a second time in March and Sager replaced it again. I only had it back for a little over a week , when it appears to have gone bad once again. It is now back with Sager for the third time (luckily I had bought the 3yr warranty). I talked with the tech support today and it sounds like they will be replacing the video gpu once again. I did a quick Google search on this nvidia chip and it became readily apparent that this is pretty much a defective chip straight from the manufacturing process. nvidia even admitted as much two years ago when they set aside $200 million dollars to fix or replace defective computers even when they are no longer under warranty. Companies like Apple recalled their's that used this video chip and others have extended their warranties by as much as 2 years to deal with this. When I got my computer back from Sager the 1st time, I noticed the fan was now running pretty much every 10 seconds. I found out that nvidia had done a software fix to the bios to make the fan run much more trying to keep the excessive heat down and thereby trying to eke out a little more life out of this 8600M chip. my question is why does Sager continue to replace this faulty chip with another faulty chip?