cdrkf
Judicious
juanrga :
blackkstar :
The discussion about AMD losing things by going bulk was exaggerated, but it is true. The general consensus on Kaveri desktop is that the IPC gains were wiped out by the fact that Kaveri can't clock as high. I don't see too many architectural changes that would have caused that. It seems far more likely to be related to the process instead.
Yeah, there are good OCing Kaveri's out there. But the fact remains that at the end of the day we had to see a stock clockspeed reduction thanks to going bulk and that the point of diminishing returns when raising TDP is much lower.
AMD lost a lot going from Richland to Kaveri in terms of clock speeds. It wasn't some catastrophic unable to break 3ghz type of event, but it was enough to hurt overall CPU performance.
Yeah, there are good OCing Kaveri's out there. But the fact remains that at the end of the day we had to see a stock clockspeed reduction thanks to going bulk and that the point of diminishing returns when raising TDP is much lower.
AMD lost a lot going from Richland to Kaveri in terms of clock speeds. It wasn't some catastrophic unable to break 3ghz type of event, but it was enough to hurt overall CPU performance.
Evidently part of the IPC increment introduced by Steamroller architectural improvements was dropped by the lower base clock. Nobody is negating that! What is being discussed here is why AMD underclocked Kaveri.
We know that Kaveri average OC on air is 4.5GHz. We have seen Kaveri benchmarked @4.7GHz:
http://www.hardcoreware.net/kaveri-7850k-overclocked-benchmarks/
Anand showed that Kaveri can be OC up to ~4.2GHz without changing the voltage (1.25V) and with almost same power consumption 147W vs 148W

We also know that early talks and docs from AMD mentioned explicitly that Kaveri was a 100W APU originally.
Thus the question is why did AMD downrated Kaveri to 95W and reduced the base frequency from the expected 4.0GHz (check my BSN article) to final 3.7GHz? Why did AMD do that when Kaveri can hit 4.5/4.7GHz on air?
This is the million dollar question that nobody is answering!
I think you're own information actually answers that question: 4ghz base is *the fastest* they could run Kaveri at reasonable power consumption levels. Given AMD's new strategy, they appear to be trying to release *something* on a very regular cadence these days (every 6 to 9 months), using minor refreshes in between the major technology changes. This is similar to Intel's strategy and is something that helps keep people interested, and more importantly builds investor confidence that things are progressing (and something AMD was very poor at before the regime change).
I personally think that Kaveri will get a mid cycle refresh to counter the Haswell update and keep things ticking over before Carizo can be released (much like they did with Richland), so keeping the initial release of Kaveri modest gives them some room to scale things up in a few months time when Kaveri 2.0 gets shipped (probably with some other tweaking under the hood as well). This is pure speculation at this point, however it would fit with their actions lately and would make sense from the business point of view as it should help keep the stock prices a bit more stable.