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Intel Turbo Boost vs. AMD Turbo Core Explained
An anonymous reader recommends a PC Authority article explaining the whys and wherefores of Intel Turbo Boost and AMD Turbo Core approaches to wringing more apparent performance out of multi-core CPUs. "Gordon Moore has a lot to answer for. His prediction in the now seminal 'Cramming more components onto integrated circuits' article from 1965 evolved into Intel's corporate philosophy and have driven the semiconductor industry forward for 45 years. This prediction was that the number of transistors on a CPU would double every 18 months and has driven CPU design into the realm of multicore. But the thing is, even now there are few applications that take full advantage of multicore processers. What this has led to is the rise of CPU technology designed to speed up single core performance when an application doesn't use the other cores. Intel's version of the technology is called Turbo Boost, while AMD's is called Turbo Core. This article neatly explains how these speed up your PC, and the difference between the two approaches. Interesting reading if you're choosing between Intel and AMD for your next build."
Not necessarily. If they're overclocking a single core, while underclocking the rest, it may all balance out to have an average core speed that's less than what it was. However, in doing this it may actually increase performance if there is a single app that requires a lot of CPU time (and isn't threaded). In reality the total speed of the computer is being reduced, while the performance as viewed by the user is increasing.
Larger caches are slower. Moving to a larger L1 cache would either require that the chip run at a lower clock rate, or increase the latency (increasing the length of time it takes to retrieve the data).
As for registers, they did increase them, from 8 to 16 with x64. IIRC, AMD stated that moving to 16 registers gave 80% of the performance increase they would have gained by moving to 32 registers.
So what you do is get people to code apps that use lighter-weight threads. Apple's GCD and FOSS ports of GCD spawn low-cost (as in overhead) threads so you can cram more in, make them smaller, and relieve part of the dirty cache memory problem in using them.
Spawn threads across cores, keep thread life simpler. Make those freaking cores actually do something. It can be done. It's just that MacOS or Linux or BSD have to be used to run the app/games.
Don't get me started on GPU threading.
---- Teach Peace. It's Cheaper Than War.
predictable performance
Predictable power-drain, you mean, and a predictable shortening of the life of your hardware -- assuming it doesn't just overheat and underclock itself, which I've seen happen a few times.
CPU scaling has been mature for awhile now, and it's implemented in hardware. Can you give me any real examples of it causing a problem? The instant I need that speed (for gaming, etc), it's there. The rest of the time, I'd much rather it coast at 800 mhz all around, especially on a laptop.
with no temperature or stability issues. YMMV.
Understatement of the year.
Overclocking is a bit of a black art, for a number of reasons. First problem: How do you know it's stable? Or rather, when things start to go wrong, how do you know if it's a software or a hardware issue? The last time I did this was a 1.8 ghz machine to 2.7. I ran superpi, 3dmark, and a number of other things, and it seemed stable, but occasionally crashed. Clocked it back to 2.4, it crashed less often, but there were occasionally subtle filesystem corruption issues -- which was much worse, because I had absolutely no indication anything was wrong (over months of use) until I found my data corrupted for no apparent reason. Finally set it back to the factory default (and turned on the scaling) and it's been solid ever since.
Second problem: Even with the same chip, it varies a lot. All that testing I did is nothing compared to how the manufacturer actually tests the chip -- but they only test what they're actually selling. That means if they're selling you a dual-core chip that's really a quad-core chip with two cores disabled, it might just be surplus, the extra cores might be fine, but they haven't tested them. Or maybe they have, and that's why they sold it as a dual-core instead of quad-core.
So even if you follow a guide to the letter, it's not guaranteed.
I'm sure you already know all of the above, but I'm at the point in my life where, even as a starving college student, even as a Linux user on a Dvorak keyboard, it's much saner for me to simply buy a faster CPU, rather than trying to overclock it myself.
Don't thank God, thank a doctor!