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Discussion on Article:
AMD Discloses Peculiarities of Next-Generation Jaguar Micro-Architecture.
The only area a longer pipeline reduces performance is in branch misprediction, as the pipeline needs to stall as it gets flushed. However, in this case and in many cases, you can get a sizeable increase in max frequency with only a minor increase in branch misprediction penalty. It says in the article that they are getting 10% higher frequency from one stage longer pipeline, so branch misprediction has gone from 13 to 14 cycles, or a 7.7% bigger penalty. Given a branch prediction rates are ~85-90% even in the Pentium days, that 7.7% increase only occurs on 10-15% of branches (which make up ~25-33% of average code).
Long story short, 10% higher frequency, smaller than 10% penalty = net gain in performance. Its about finding the optimal point between reducing stage propagation delays (the returns get smaller the more stages you add) and the increase in branch mis-prediction (which increases linearly with pipeline length). Prescott didn't work for many reasons, not just pipeline length (which has 31 stages long, far longer than Jaguar anyway). Just saying longer pipeline = no improvement without even a basic analysis of the architecture is just incorrect.
Where is shared FP and other resources?
Dirk, Rory is betraying your legacy which you had been bearing so many years.
Would has it not been better to use sharing for FP and AVX? Would it?
Shared Fetch and Decode would have been of some use to lower power consumption in low performance cpus. Wouldn't it?
If you don't like AMD then thats fine, but surely everyone wants some competition so that innovation keeps bubbling away and prices stay reasonable? You should thank hardcore AMD fans who take the hit and buy slower AMD processors, indirectly they are helping you buy cheaper more powerful Intel one's.
I still build AMD systems exclusively and my customers are VERY happy. An AMD triple will do any job your average user wants to do with plenty of cycles left over, and the quads and hexacores tear through games like nobody's business. I'm typing this on a Thuban hexa after just blasting through some Crysis II,no lags or hangs.
So how about quitting the fanboyism and accepting that competition is GOOD and thanks to AMD I can sell $450 quad core systems and still make a nice profit.
ppl saying AMD is finished/die would have a very rude awakening should this ever happen because then we all would be paying a lot more for those precious intel CPU's
Both consoles will have AMD Jaguar Micro-Architecture CPU's and Graphics core next GPU's... looks like they pulled off one hell of a CPU
Ohh and the product they will be selling is a custome "8" core Jaguar CPU~
Sony should of went with Nvidia Project Denver 20nm (ARMv8 + Maxwell GPU)The PS4 would of been 2x faster then AMD Jaguar crap! Right now Nvidia has the fastest GPU for PC on Earth! GeForce GTX TITAN.
Microsoft should of used Intel 14nm Broadwell (HD Graphics 5000) Eighth generation GPU! Also would have been 2x faster then what AMD has to offer MS Xbox!
AMD has nothing to compare with 14nm Broadwell (Intel 5th gen CPU+GPU.
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