XBONE having problems with eSRAM yield. Crazy Buttocks confirms.

[ethomaz]

drkohler said:

A few corrections here. First, the initial yields likely are in the 20+x% region.  TSMC/GF are just starting with the production of the chips and initial runs usually start at very low yields. The calculation would roughly be $7000 / 50 = $140 per APU for PS4 and $7000 / 30 = $230 for XBox One (The manufacturers very probably lose money at this initial stage, only when yields go up will they recover the initial losses). Of course the wavers don't cost $7000 (probably very roughly $50-$150 per waver, that depends on waver type and quality used), it's the production that costs that much.
There is also a misconception running around on the web that eSRam is a problem on the XBox APU. This cannot the case. Memory is one of the things that is engineered with heavy redundancy in mind (there is a little more than 32MByte eSRam on the die, so bad blocks can be swapped with good surplus blocks, oldest trick in the world really). So eSRam actually INCREASES yields because errors in the eSRam block can mostly be "repaired". Both APUs have redundant parts and non-redundant parts (CPU, obviously, one bad core and into the trash the APU goes). The GPU is bigger on the PS4 die, but since only 18 of the 20 units are enabled, this part is redundant. In general, the XBox APU has more non-redundant parts so it will ever be more expensive than the PS4 counterpart.

I agree... and the numbers used are not real... I just used them to try to explain... I really don't know the real cost of the Wafer and how much chips can be made for PS4 and Xbone... but the last part is true Xbone's APU will be always more expensive than PS4's APU (5 billion vs 3 billion transistors... > 400mm² vs. < 300mm²).