Die size bug?

Hello guys, i have weird problem,On GPU-Z die size shows 77mm2 but on https://www.techpowerup.com/gpudb/b2676/xfx-r7-250-low-profile says 90mm2?
Could that be their bug?Cause on official XFX site i couldnt find any Die size information..

g6r.png


 
For Ati cards with Gpu`s of a few years old the two ISO processes used for the die size in Nm scale were 90nm
And 65nm, then the gpu`s were also shrunk down to 55nm parts

R7 200 SERIES Gpu`s can be 55nm to 28nm parts.

Where as older Ati cards branded as 7900 series could be 90nm parts or 65nm parts.

Ati did a refresh of gpu die sizes twice a year as the node processing quality and quality of the silicone coming out of the fab factory's were refined. And also a few tweaks to the Gpu cores when doing this.

So you often have a mix of gpu die sizes.