Linked by Thom Holwerda on Thu 28th Jan 2010 20:21 UTC
Hardware, Embedded Systems And yet another item on the iPad? Are we serious? Yes, we are, since this one is about something that even geeks who aren't interested in the iPad itself should find intriguing. Steve Jobs said yesterday that the iPad is powered by an Apple A4 processor, but contrary to what many seem to think - it wasn't designed in-house at all.
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RE[2]: Comment by re_re
by lemur2 on Fri 29th Jan 2010 09:34 UTC in reply to "RE: Comment by re_re"
lemur2
Member since:
2007-02-17

Even at the high end ... larger machines these days are often merely arrays of tightly-interconnected smaller processors. Google are a good example of this. A large array of x86 machines draws a lot of power, whereas an even larger array (numerically) of ARM devices might be able to achieve the same performance (for applications such as Google) at lower cost and much lower power consumption.


Speaking again of the high end and Intel versus ARM, here is a high end CPU family from Intel:

http://www.phoronix.com/scan.php?page=article&item=intel_core_i7&nu...
The current Core i7 processor selection includes the 920, 940, and 965 Extreme Edition. All three of these processors are quad-core parts, but Intel has brought back Hyper Threading, which means the logical core count is eight. For each of the four cores there is 256KB of L2 cache, while 8MB of L3 cache is shared between all of the cores. With Intel evidently not being interested in Linux results for their Core i7 series, we had received no review samples of the Core i7 series. However, we ended up purchasing an Intel Core i7 920 for this round of testing, which comes clocked at 2.66GHz. The Core i7 940 is clocked at 2.93GHz while the Intel Core i7 965 Extreme Edition runs at 3.20GHz. The Intel Core i7 920 currently retails for just above $280 USD.


http://everythingapple.blogspot.com/2009/11/imac-core-i7-power-util...
TDP of the Lynnfield Core i7-860 CPU is only 95 Watts (not 100) at max usage


Now that is a considerable amount of grunt for a microprocessor CPU, but it eats 95 Watts!

OK, now consider a modest 32-bit ARM Cortex A9 CPU @ 2 GHz. Apparently it uses under 2 watts. One could run over 40 ARM Cortex A9 CPUS with 95 Watts. That comes to 80 cores. That is ten times as many cores ... admittedly only 32-bit cores, and clocked slower, but still.

For some applications, those amenable to load sharing, perhaps this discussion might indicate where the future is ...

Edited 2010-01-29 09:37 UTC

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