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    question about TDP

    Discussion in 'Hardware Components and Aftermarket Upgrades' started by laptopnoob678, Jan 29, 2017.

  1. laptopnoob678

    laptopnoob678 Notebook Consultant

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    So, TDP is the heat output by a CPU under load?

    How can a CPU like a Celeron B710 (1 core @ 1.6GHz) have the same TDP as an i7-2640M (2 cores @ 3.5GHz)?

    Both 32nm and with the same specs everywhere else (if not better for the i7)

    Would a B710 under load actually output the same heat as the 2640M?
     
    laptopnoob678, Jan 29, 2017
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  2. smartuy

    smartuy Notebook Guru

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    TDP is power used by the CPU

    Sent from my SM-G930V using Tapatalk
     
    smartuy, Jan 29, 2017
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  3. GeforcerFX

    GeforcerFX Notebook Enthusiast

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    they don't use the same power, but intel puts them into the same tdp class. This tells the OEM the type of cooling they will need more than anything else. The major difference between the cores would be the quality of the silicon, celerons are made from the dies that tested to be lower quality, the other is usually your better silicon from the wafers, better silicon can run at higher clocks with lower voltage creating less heat.
     
    GeforcerFX, Jan 30, 2017
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  4. John Ratsey

    John Ratsey Moderately inquisitive Super Moderator

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    It's a valid question: Why would two CPUs from the same generation and with the same design power rating have such different levels of performance?

    The Celeron will be one of the chips left in the bottom of the bin having failed all the tests for being sold as a faster (and more expensive) CPU. Intel don't like waste so sell it for a few $$$s as a basic CPU which might need higher voltage to keep it stable and with a bunch of features disabled. In reality, however, it's likely to run well within the design power rating.

    The i7-2640M, on the other hand, is one of the chips on which all the features worked and which testing showed was able to run faster within the design power rating (and most likely at or beyond the upper end). In reality, seeing it run at full speed is as easy as finding a quark.

    Moving one step forwards in Intel's process, I had two identical notebooks except one had the i5-3317U (max 2.1GHz) and the other had the i7-3535U (max 2.6GHz). The faster CPU was slightly above the TDP rating and took the cooling system of the notebook to the limit. I actually preferred the slower CPU as it ran comfortably within the design power rating and the cooling fan could run slower and quieter.

    John
     
    John Ratsey, Jan 30, 2017
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    TomJGX, tijo, GeforcerFX and 1 other person like this.