[The ratio (around 60% of the PSUs rated load as I recall) makes sense if Nintendo were taking into account PSU aging which seems likely, as Nintendo are known for making very reliable hardware that just keeps on going for years and years.]
http://www.tomshardw...ing-calculators
We can ignore it and Nintendo could rated it 75 watt with in mind that PSU ages so it could be higher. it is maybe 5% in its entire life time.
[When I compared the Wii U power consumption against the maximum the PSU is rated to output, the ratio was around the same as the Wii power consumption against its PSUs rated maximum. That suggests to me that the Wii U is drawing close to its design power already.]
I must disagree.
[So yes the load may increase once developers really start tapping into all the hardware, but I don't think a firmware update is going to magically unlock more SPUs. For one thing, the scan of the chip has been extensively examined and 320 SPUs was decided to be the most likely MAXIMUM based on its structure. If it had double or triple that number, I'm pretty sure the experts would have seen that.]
Did you forgot that the GPU inside Wii U is heavily customized and I know it is VLIW4 base plus there are no VLIW4 GPU's of any kind using eDRAM or having exactly 320 SPU's. Nintendo is known for doing heavy customizations to the GPU and they will not waste any mm^2 of silicon thus they will resort to removing features and some obviously unneeded also I looked at die shot and I can't find on what eletroscope it was taken and can we even see a single transistors? If it was taken on eletroscope that can go below 40nm then we could have seen individual transistors and other features.
Also it is 40nm and made on more mature and refined process than original VLIW4 Radeon HD 6000 series, there was a rumor it is based around HD e6850 and very first alpha Wii U devkit had Radeon HD 4870.
Wii U's GPU is 146mm^2 and we remove eDRAM and small eDRAM block and we have 100mm^2 for GPU and Radeon HD 6850 is 250mm^2 and has 960 SPU's and having just 320 SPU's would be 83mm^2 though we know it is customized and not off-shelf GPU so I am sure there will be more SPU's and we know that GPU is produced at mature 40nm Advanced CMOS at TSMC so performance is higher and power consumption is lower.
Gah i won't argue with you.