[QUOTE="Bligmerk, post: 6198283]There are several suspicious things going on with this "good news". The 150 MHz "upclock" (MS is making a big point about it not being an overclock) or 10% CPU clock speed increase has multiple problems that prevent it from being "good news". One thing is announcing it a day before a leaked shipping boxes photo. MS is saying this "upclock" was proven out several months before production had started.
AMD stated earlier in the year, the standard clock rate for the Jaguar CPU would be 2GHz, and that 1.6GHz would be shipped for devkits. From this news straight from MS, they somehow locked in their APU design with the 1.6GHz CPU, and the "upclock" is raising it to 1.75GHz. There are no indications Sony designed the devkit CPU into the PS4 APU and their production units have the Jaguar at the standard clock rate of 2GHz. The Sony FCC report, which Sony didn't hide, showed a maximum clock frequency of 2.75GHz. Many people are insisting this is the Wifi frequency but under this number, there is a category specifically for Wifi frequencies, separate from the maximum frequency. There were rumors that Sony tested at 2.75GHz CPU and had no problems but were shipping with the standard 2GHz.
2GHz > 1.75GHz
The other problem with this "upclock" is that even MS acknowledged in their xbits presentation there was increased heat dissipation. MS said it would only result in slightly more fan noise. During this time frame, there was the announcement of the sudden shutdown of death feature, due to overheating.[/QUOTE]
It would really come down to power budget and device yield at speed within power budget.
While AMD can crank out good functional 2GHz units, can they yield enough within power constraints that MS has set? That is what the real question becomes. The lower the yield on this, the higher the price would be.
While the design and intent to hit a power budget is there, it's not a guaranty. You're going to have a distribution of devices with varying amounts of leakage current (which becomes ever more dominant as the major power contributor as we go to smaller and smaller process nodes.) Leakage current of a nominal devices may be moderate, but the question is what the distribution of material looks like to see if you're getting > 90% of the devices within the power budget or < 50%. Going up small percentages in frequency has a direct impact to dynamic power by the square of the ratio of the frequencies, but also you need to bias the core voltage level higher to operate at the higher frequency and you can crank the dynamic power up again another factor by the square of the ratio of increase in voltage level applied. Now that's not the end of it, the higher voltage level further increases the leakage current of the device. This is basis of why in the report regarding the 150MHz increase has a potential increase of power by 66%. That number wasn't pulled of ones ass, it's realistic.
I'm sure they have a power limitation for their thermal solution of their system - If they don't they're not doing their job, and I'm sure they're doing their job. And with this, they have to look at what the yielding would be and this tends to be a steep fall off curve on todays processes. So they could have stayed 1.6GHz and had awesome yield and not the optimal performance, or go up to where they have acceptable yield and better performance.
Note that as time goes by, there will be tweaks to the process, and targeting of N2P ratio's and the like to get better yield at power. But that doesn't help you with early production.
I'd guess they planned for 1.75GHz a good while back and went with a lower yield initially, in the hopes that by the time the ramp production they'd have better yield. This would have given the option of moving forward w/ 1.75GHz for everything, or falling back to 1.6GHz (including on the units built with 1.75GHz yielded earlier units. It's would simply be a FW update to change the PLL settings of the device to run it at 1.6GHz - after all you want all production units to operate at the exact same performance level.)