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I recently bought 2 Sony laptops with the following specs:

Laptop 1

Intel(R) Core(TM) i7-3520M CPU @ 2.90GHz
8GB RAM
NVIDIA 640M LE 1GB
500GB (7200rpm)
direct rendering: Yes

Laptop 2

Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz
8GB RAM
NVIDIA 640M LE 1GB
500GB (7200rpm)
direct rendering: Yes

I installed Xubuntu 12.10 (64 bit) on both of them, and then set them up identically:

  • Installed the same apps
  • Installed the same plugin versions (Flash)
  • Identical BIOS version
  • Identical BIOS options

For most of the tasks both of them perform similarly. However, using Chrome and Firefox and doing some heavy browsing (opening multiple tabs while pages are loading, etc...) the i5 outperforms the i7 noticeably.

When watching HD videos on Youtube, the i5 is smooth, while i7 chokes after opening a couple more tabs.

Using htop I see that i7 cores work at 100% when things start to slow down, while the i5 cores never get past 60%.

Why is i5 performing better than i7? If the i5 really does handle these things better than the i7, why should I pay more for an inferior product?

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My guess would be that the rest of the notebook is the problem, not the i7. It may not have been designed well (their first i7 compatible board perhaps?), the thermals may suck on it, etc. Here's something to try (if they are actually identical otherwise, which I highly doubt), swap the CPUs between the notebooks and see if the problem follows the i7 CPU. – techie007 Dec 22 '12 at 17:28
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Sounds like a good guess to me. Swapping CPUs would be out of the possibilities due to warranty stuff. Thanks for the comment! – Pete Darrow Dec 22 '12 at 18:40
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closed as not constructive by Xavierjazz, Breakthrough, Dave M, techie007, Nifle Dec 22 '12 at 19:13

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2 Answers

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You need to check actual runtime CPU frequency. The 'i' series dynamically alter frequency, so at idle both processors will have like 0.5-0.8 Ghz frequency, but at heavy load it will increase, even beyond specified value (i5 and i7 have "turbo boost" technology that can increase frequency even furver).

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up vote -3 down vote

--> Change the power settings to high efficiency.

Depending on your operating system, on Linux I can't remember, but on Windows this should be like this: Start menu > Power options > select high performance / speed profile.

The reason is that OS' kernel adjust the CPU run speed (=power usage) depending on the power profile that you have configured (and depending if you are running on battery or AC).

When the run speed is set to "slow", the CPU usage will show as 100% (even though it's not running at full power).

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The Asker specifically said that they are using XUbuntu – neersighted Dec 22 '12 at 18:19
What? Pete says in his question that he installed Xubuntu on both computers. What "Windows power settings" got anything to do with it? – mnmnc Dec 22 '12 at 18:20
I have modified the post to match ALL operating systems. (I have experienced this by myself) – user182109 Dec 22 '12 at 18:22

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