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• #34 stratova veterán Meteorhead #33

  Új Válasz 2016-02-11 14:25:29 #34

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  stratova

  veterán

  válasz Meteorhead #33 üzenetére

  Csak be kellene paraméterezni azt a szerencsés APU-t:

  Felhasználói eredmények, melyeket eredetileg Dhampir kolléga talált:

  A10-8700P 15 W Toshiba

  I managed to use this trick on a Toshiba laptop with a FX 8700P. It's got low end cooling and a 19W TDP limit so i had to settle for a maximum boost clock under sustained load of 2.8Ghz at like 0.900v (roughly). Nonetheless this has boosted performance a bit as it was rarely getting over 2.2Ghz at stock voltatge settings and would even drop to 1.8Ghz under heavy load. Now it holds 2.8Ghz under all but extended prime95 small FFT where it sometimes drops to 2.6Ghz.

  FX-8800P 35 W Lenovo Y700

  In my case (Y700), Prime95 results in 3.3GHZ actually.. but as I said, Crysis 3 or other gaming type load (which is not as heavy as Prime95 maybe) results downclocking of the CPU to 1.3GHZ (or 2.1GHZ if I use this tool). The difference in FPSs is huge in Crysis 3. I don't really think the FX-8800P has any problem to do 3-3.3GHZ in the Y700, but it seems like there is the usual problem with the EC/bios algorithm that controls the clocks or something ..
  ...That is more or less the point. The cooling system is not powerful enough to keep max. CPU turbo while the dGPU is under load. That is the case with most of the notebooks out there, usually the BIOS would lower turbo clock of CPU and/or GPU to prevent overheating (sometimes even below base clock).

  In our case, Lenovo did set a temperature target of 85 degree (c) for both, CPU and GPU. If one chip reaches this temp. the CPU will switch to its lowest power-state, until then it will keep up max turbo which makes no sense at all. A typical behaviour would be to lower the P-state step by step when reaching certain temp. targets (as the Intel based Y700 does starting at 65 degree). The cooling system is capable enough to maintain APU clock speeds between 2.1 and 3.0 GHz but the logic for that is simply missing in the BIOS.

  Never versions try to address this throttling issue by limiting max. turbo clock of the dGPU, but that does not work and is more an "half hearted" attempt that will reduce overall performance for nothing. It seems Lenovo is not interested in resolving this, so we had to take action by ourselves.....

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