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I have a Lenovo P50. It has 4 memory slots and I bought 4x 32 GB Crucial memory.

It seems like the hardware recognizes 128 GB. At least, Windows 10 says "128 GB, 64 GB reserved for hardware" in Task Manager.

However, during boot, the diagnostics screen says 65536 MB RAM and within BIOS, it also says 65536 MB installed memory.

I tried:

  • disabling the built-in graphics card in the BIOS, so it does not use memory. I'm using the NVidia graphics card only.
  • running msconfig and using the advanced options to set memory to 131072 (128 GB)

Any chance I can use 128 GB on this model by applying some other trick?

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    The information I can find on a Lenovo P50 suggests some options might have an i7-6700HQ and the processor itself is limited to 64GB RAM: ark.intel.com/content/www/us/en/ark/products/88967/… The same limit also applies to the Xeon version.
    – Mokubai
    Nov 29, 2023 at 22:01
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    All mobile Skylake CPUs max out at 64GB. Ditto for Kaby lake. You need >=Coffee Lake laptop to go beyond 64GB :( (for example i5-9400T is a mobile CPU supporting 128GB RAM)
    – hanshenrik
    Nov 30, 2023 at 11:46
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    Out of curiosity, what task do you need 128GB RAM on only a 4-core CPU for? Some large FEA?
    – Therac
    Nov 30, 2023 at 13:12
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    The "128 GB, 64 GB reserved for hardware" might be Windows reading the SPD EEPROMs on the DIMMs to find out the true capacity. It's not uncommon for the memory presented to the OS to differ from the physical size of the DIMMs because bits of RAM get taken by firmware for various things. In this case the system can only address half the RAM and the rest is labelled by Windows as 'reserved'. Nov 30, 2023 at 17:35
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    @ThomasWeller don't do that on a 2016 Skylake laptop. Buy a desktop computer for that, and set it up with remote access to your laptop (rustdesk/ssh/teamviewer)
    – hanshenrik
    Nov 30, 2023 at 19:38

3 Answers 3

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According to the specifications, the P50's max memory is 64GB:

  • Chipset: Mobile Intel CM236 Chipset (Intel GL82CM236 PCH)
  • Memory: 64GB max⁷ / 2133MHz DDR4, ECC or non-ECC (ECC function supported only on Xeon processor), dual-channel capable, four DDR4 SO-DIMM sockets

ThinkPad P50 Platform Specifications

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    Those specs are not always reliable; they might just mean "we only had 16 GB RAM modules to test, so we state 64 GB to cover our asses in case someone buys 4 32 GB modules in 2 years and it doesn't work". But the processor model gives the problem away. Nov 30, 2023 at 18:26
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    @GuntramBlohm Agreed. But they're also the supported specs, so if you do call Lenovo up saying "Hey, my 128GB isn't working" they're going to tell you to get lost.
    – squillman
    Nov 30, 2023 at 19:46
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    @GuntramBlohm the Intel Spec pages for processors that that will work in the laptop are also adamant that the processor itself only supports 64GB. That isn't likely to be just a "we haven't tested it", if the CPU manufacturer themselves say it then most likely it is part of the hardware design of the silicon itself.
    – Mokubai
    Nov 30, 2023 at 22:28
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    The laptop specs are not always reliable. I have 16 GiB of RAM working in an Lenovo ThinkPad X220 even though the official manual says it only supports up to 8. Luckily, people on forums already did the testing before I placed the order for bigger RAM sticks.
    – Nayuki
    Dec 1, 2023 at 15:22
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Seems Lenovo P50 use Skylake. All mobile Skylake CPUs max out at 64GB. Ditto for Kaby lake. You need Coffee Lake or newer to go beyond 64GB on a Intel laptop :(

For example i5-9400T is a mobile CPU supporting 128GB RAM (And to the best of my knowledge, is the /first/ mobile Intel CPU supporting over 64 GB RAM)

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    There are of course some laptops made that don't use mobile CPUs; those would have a different limit. To get >64GB on an Intel laptop, you could have used one of these, even before Coffee Lake.
    – Ben Voigt
    Nov 30, 2023 at 19:07
  • @BenVoigt good point! Many Clevo-laptops use desktop CPUs, for example! (and many no-name laptop producers buy their laptops wholesale from Clevo and re-brand them~)
    – hanshenrik
    Nov 30, 2023 at 19:29
  • @hanshenrik Fascinating. Does that mean that the CPU in those laptop is in a proper socket like a desktop part and not soldered down like in other laptops these days?
    – TooTea
    Nov 30, 2023 at 20:08
  • @TooTea good question, I don't know. I have some old Multicom.no laptops, which are Clevo re-brands (one with an i7-6700 desktop CPU), I could open one up and check.. One day i'm home and bored, which certainly isn't today
    – hanshenrik
    Nov 30, 2023 at 20:12
  • @TooTea: Possibly socketed but not guaranteed, since Intel and AMD both also sell SKUs of desktop-class processors for soldering as "embedded system" CPUs.
    – Ben Voigt
    Nov 30, 2023 at 21:36
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It seems like you bought Crucial memory but have not taken a look at its page of Lenovo ThinkPad P50 | Memory RAM & SSD Upgrades.

Here is what it says :

enter image description here

This fact is confirmed by your experience - your motherboard cannot handle more than 64 GB.

For being safe, I suggest using the Crucial Upgrade Finder to scan your hardware and give you offers that are guaranteed by Crucial to be correct and working.

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