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Rich Edmonds

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Dec 13, 2010
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can someone explain this to me? i've had single core computers and single core blackberrys with true multitasking for years now, why does WP7 need two cores?
With a single core processor, you can only have one core that handles every calculation that is sent through the chip. With dual core (or triple/quad core) there are two or more "cores" that can handle different (or the same) calculations with higher clock rate and efficiency. This, of course, depends on limitations of the software running on the system.

The largest boost in performance will likely be noticed in improved response-time while running CPU-intensive processes, like antivirus scans, ripping/burning media (requiring file conversion), or file searching. For example, if the automatic virus-scan runs while a movie is being watched, the application running the movie is far less likely to be starved of processor power, as the antivirus program will be assigned to a different processor core than the one running the movie playback.

The above is an example for a PC. While one core is enough for multiple applications to be used on mobile devices (which is given the term 'multi-tasking'), two cores is by far more efficient due to applications being ran on separate cores etc. So we could run Angry Birds on one core, quickly switch applications to check email on another core (while Angry Birds is 'truly' running) and return to the game with little latency (depending on the OS). With a single core, Angry Birds wouldn't run entirely in the background due to the email app using the single core (in theory - depends on how much CPU the email app and transition/multiple application manager requires, and how the OS is built).

Mainly a performance boost in CPU hungry apps.

EDIT:
He's talking at a very basic hardware level, you can't truly do two things at once (by that I mean in the same exact instance in time) without two logical processors. Multitasking in the way we're all used to talking about it is achieved through multi-threading and the use of the processor's cache to queue operations coming from different programs/routines

Damn, you beat me, sir :)
 

spitothec

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Nov 9, 2010
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So multitasking is possible on a single core using threading, but much more efficient on a dual core? Or am I still not understanding? hahah I'm just wondering because I've been able to run apps in the background on BB's, but like you mentioned, it was definately a power hog and slowed things down (ie: Google Maps). Thanks for the explanation :)
 

Jay Bennett

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Nov 2, 2010
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So multitasking is possible on a single core using threading, but much more efficient on a dual core? Or am I still not understanding? hahah I'm just wondering because I've been able to run apps in the background on BB's, but like you mentioned, it was definately a power hog and slowed things down (ie: Google Maps). Thanks for the explanation :)

Almost, it ultimately comes down to that everything on a processor happens in time with the clock, at a certain interval (that's the clock speed, 1ghz in our devices). At each clock pulse the processor can perform one logic operation.

Ordinarily that would mean we have to perform a series of operations for one application/routine, until it's finished and releases the processor.
With threading we can queue independent logic operations and each thread will be given time on the processor, with it often being the case that the threads will each 'take turns' as the processor for instance does work for thread 1, then 2, then 4, then 2 again, then 1 (that's just an example that they don't have to be in order, each thread will be assigned a priority).

With dual or any multicore, the processor can perform n number of operations (n being the number of cores). So a high priority thread (e.g. a virus scan) can be fully taxing one core, whilst a medium priority thread (e.g. playing music) is still actively operating at the exact same moment of time.

If you're wondering then why multi tasking seems to work fine on single cores it's because all of this happens so quickly (1ghz processors are operating at 1,000,000,000 clock pulses per second, so can do 1,000,000,000 logic operations per second)

That's a really simple version of how it happens and apologies if it's not completely clear, it's been a while since I learned all this stuff.

EDIT: Oh, and the reason things then appear to slow down in your example is because the threads for the application you're using are being queued behind other threads from the other applications.
 

eric12341

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Dec 1, 2009
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Had the phone for almost 4 hours now and it is great. Very smooth copy and paste is included and there is some multi tasking but not for everything. U can listen to music in Zune, text and browse in IE at the same time
 

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