Quote Originally Posted by savantu View Post
http://www.icknowledge.com/misc_tech...calculator.xls

It is an Excel model ; insert chip dimensions , wafer size and calculate for 0.25 and 0.5dd.

It's easy.

Gross die 237

0,25dd/cm^2
Exponential 144 good dies , yield 61%
Murphy 129, yield 54,6%
Poisson 124 , yield 52,7%
Average ( best+worst/2 ) 134 yield 56,5%

0,5dd/cm^2
Exponential 103 , yield 44%
Murphy 75 , yield 31,8%
Poisson 65 , yield 27,8%
Average 84 yield 35,44%

Again , I consider 0,5dd more representative.Based on that , ATI gets 7-8x the number of high end chips per wafer vs. NVIDIA.
No offense, but I find it funny that someone on a forum with an excel spreadsheet for approximating yields thinks they know about yields as though NVIDIA didn't know exactly what they would be dealing with before making their chips. Sorry, but when millions of dollars are at stake, you know these things ahead of time, and you calculate around that. Sure it can fluctuate a bit below what you might expect, but not much.

People making a thread like this seem to think that these guys make wafers and just pray they'll get good yields. When people say good or bad yields ,this isn't a major swing. It's a matter of a percent or two. So it's not the difference between 80 or 20 dies like some seem to believe.