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Core i7-750S: 82W TDP

Intel Core i5-750S: Since When Does The S Mean Slow?
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Based on exactly the same silicon, the S-model looks and feels like the regular Core i5-750. The main difference in everyday operation is its maximum power, which is limited to 82W instead of the regular 95W. This 13W reduction isn't nearly as impressive as the 30W drop it ensured with the Core 2-class equivalents.

Most likely, the new specifications will limit power consumption and thermal dissipation to levels suited to components created for a 65W power envelope. Idle power isn’t an issue, and system peak power consumption is clearly lower on the Core i5-750S than on the regular model. From this perspective, Intel’s S-model lives up to expectations.

However, Intel doesn't seem to have introduced any special options that would allow these processors to run at decreased voltage levels. Ultimately, such options are what made all of the existing Core 2 S-class CPUs more efficient.

Intel instead applies a much simpler tweak to bring power down. It reduces the nominal clock speed by 266 MHz and disables the Turbo Boost feature when three or four processing cores are under load. Fortunately, the acceleration feature remains active when only one or two cores are taxed. All voltage levels seem to remain identical, at least on our test system.

We found that the performance impact from reduced clock speeds is pretty noticeable. On one hand, quad-core performance is impacted a bit, which alone isn’t much of an issue. The trouble with Turbo Boost only working with one or two cores, though, is that modern operating systems will aggressively distribute threads across all available cores, meaning that in many workloads you will get average workloads on multiple cores. The end result is Turbo Boost staying inactive. Only manual adjustment of thread affinity or true single-threaded applications will yield the Core i5-750S running on par with the regular i5-750. This isn't a caveat we were forced to make previously in analyzing the Core 2s.

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  • 5 Hide
    mi1ez , 3 March 2010 14:44
    Oh dear Intel. What have you done.
  • 5 Hide
    Anonymous , 3 March 2010 20:03
    I'd like to know how it looks like when you under-clock the regular i5-750 to the reduced speed of the i5-750s. I wouldn't wonder if you could reach the same reduction in power consumption with the regular one, so that spending money on the i5-750s would be a complete waste.
  • 0 Hide
    Anonymous , 3 March 2010 22:27
    The MSI website shows the correct BIOS version for a i5-750S on a P55-GD65
    is 1.6.
    Could the poor results be due to the tests being carried out with the earlier v1.42 BIOS?
  • 3 Hide
    silverblue , 4 March 2010 17:45
    When AMD bring out a lower power model, they adjust the numbering to match the CPU speed (if changed) as well as adding an E at the end, for example 2.6GHz 910 -> 2.5GHz 905e. Intel have effectively tried to pass this off as a more efficient 750, which is obviously wrong.
  • 5 Hide
    plasmastorm , 4 March 2010 18:15
    Quote:
    You decide what the S means now.

    SH** ?
  • 0 Hide
    Solitaire , 4 March 2010 19:43
    MWi - Probably. The catch is that Turbo Mode would bring the power dissipation back toward the original TDP, thus the mess that is i5-750s! I'd still take an i5-750 over the tripe above anyday! :p 

    Why did they even bother though? They should have done this kind of malarkey with the i5-530/i5-650/i7-860 to take advantage of the HyperThreading! Most apps or games that couldn't take advantage of HT would most likely focus on one or two cores anyway, thus triggerring Turbo Mode unless you have a ton on in the background!
  • 1 Hide
    Anonymous , 8 March 2010 00:07
    /rant
    Core i5 750 for a gamer on a budget? What are the lower ranked Corei5s and Corei3s for then? Is it just me or are hardware reviewers somewhat spoiled and decadent sort? I'm guessing a Radeon 5870 is a budget gaming card as well?
    /rant