Is it worth upgrading from i7 3840QM to i7 3940XM on HP 8770W?

Discussion in 'Hardware Components and Aftermarket Upgrades' started by mirage_bg, Oct 21, 2019.

  1. mirage_bg

    mirage_bg Notebook Evangelist

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    What is your opinion, would you do such an upgrade?
     
  2. tilleroftheearth

    tilleroftheearth Wisdom listens quietly...

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    See:
    https://www.cpubenchmark.net/compare/Intel-i7-3840QM-vs-Intel-i7-3940XM/900vs1482

    Why? Not only are you increasing the TDP by 10W or 22%, but you are also only moving sideways on the overall performance scale (vs. any modern processor).

    Keep a working system as-is and enjoy as long as possible. Just because upgrades are possible doesn't mean they should be done. ;)

    And my reasoning above is at $0 cost too. When you take into consideration the $$$, time and risk of doing such an upgrade, it is even less desirable, IMO.

    What is your reason for requiring more firepower? Gaming or paid work? Both? You'll have to weigh the cost/benefits for yourself.
     
  3. bennyg

    bennyg Notebook Virtuoso

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    Many potential issues
    CPU cooling (do you have headroom)
    Can the VRMs handle it (what do others achieve in your model)
    Is the BIOS sufficiently unrestricted

    I'm testing my custom watercooling project with 3940XM @ 4.6ghz, a decent improvement over the un-powerlimited 3740qm @ 3.9ghz which is itself a big jump over stock, but that is using an insane level of cooling and an unlocked+modded main bios (on a platform that has significant headroom e.g. I've previously shoved over 500W through it - over double the stock config - via power modded GPUs) which are things that I'm guessing you won't have on your HP.
     
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  4. yrekabakery

    yrekabakery Notebook Virtuoso

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    The i7-3840QM is already partially unlocked (4 turbo bins), which means it can be overclocked to 4GHz on all cores using ThrottleStop or XTU. A 3940XM might be able to go slightly further, at the cost of much higher demands on system cooling and motherboard/PSU power delivery, which your system may not be able to support. Since pre-Haswell mobile CPUs don't expose fine-grained voltage controls, you're kind of at the mercy of whatever voltage table is programmed into the chip, which is almost assuredly too high. So all in all, I don't think upgrading to an XM in your particular situation is worth it.
     
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  5. mirage_bg

    mirage_bg Notebook Evangelist

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    Unfortunately any O/C is not possible on 8770W - locked on a bios level. So no XTU, Throttlestop etc.
    I wanted to squeeze the max out of my 8770, but maybe you are right - 55W will be a lot of heat and the performance gain won’t be so big probably. Now my 3840QM is maxing out at 72-74C both CPU and GPU heavily loaded.
     
  6. ole!!!

    ole!!! Notebook Prophet

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    then its probably not worth it unless you are looking at a very cheap cpu here.
     
  7. SamuelL421

    SamuelL421 Notebook Enthusiast

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    I wouldn't recommend it. My 3920xm gets toasty, even with liquid metal applied to both it and my M5000M. It rarely throttles but I think it negatively impacts my ability to OC the M5000M. If I want to put a decent OC on my M5000M or do a long gaming session at a LAN event I end up using an OPOLAR cooler to keep everything from throttling.(https://www.amazon.com/gp/product/B01NACVLWM/ref=ppx_yo_dt_b_asin_title_o01_s00)
     
  8. mirage_bg

    mirage_bg Notebook Evangelist

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    What are your CPU/GPU max temps under heavy load?
    I applied LM to my 3840QM and the temps are 70-71C under Prime95/Aida64 Stress test/XTU Stress test and 75-77C under heavy 3D load together with GPU (same as yours- M5000m OCed 1200/2700, 0,987V, 67C max temp)
    As my GPU is still on Kryonaut, I intend to apply LM on it also, as I want to use it with Prema vBios which allows me to rise the clocks to 1400/2700 at 1.087V, but on Kryonaut the temps are rising up to 88-90C with this vbios...
     
  9. SamuelL421

    SamuelL421 Notebook Enthusiast

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    Both CPU and GPU will creep past 80 on heavy load - I don't remember how high the GPU goes if left unchecked but it definitely begins to throttle. If I use the external cooler it stays significantly cooler - I'll have to test and let you know for the exact figures. I'm currently running the M5000M with the core just over the 980m boost (maybe 1130-1150? Can't recall and at my desktop currently). Mind you, this was with 2 full tear down and repaste of LM on both GPU and CPU along with fujipoly pads (explanation below). In any case, I think my cooling fan may be worn / not working at 100%, part of the explanation for those higher temps, but I also think the 3920 contributes to the problem.

    I ended up applying LM 3 times thanks to those fuji pads, which I wouldn't necessarily recommend for LM. I used fujipoly for GPUs before with kryonaut and never had an issue. Didn't occur to me at the time but the fuji pads have very little "give" to them and created very slight tolerance issues where the heatsink was not tight against the GPU. Much less of an issue if you are using a blob of paste, but with LM being such a light/thin application, it becomes an issue and caused worse temperatures than the previous kryonaut until I swapped the fuji pads for thinner ones.
     
  10. kingofswag187

    kingofswag187 Notebook Deity

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    If you overclock with coreboot, sure.
     
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