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Bullshark
SCSI Port
Posts: 53
Registered: ‎08-13-2016
Location: US
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Message 1 of 24

Do I need to install RAM in pairs?

I have an a model I got with 8GB because I wasn't gonna spend 100 bucks more for 16GB. I see that I can buy a RAM card for like 40 bucks. However, does it have to be the exact same brand and/or size? I know the RAM in this thing is DDR4-2133 SODIMM; according to Crucial and Newegg, I can buy another card for 40 bucks or so of the same type of RAM.

 

Can I buy a 4 GB to add onto the 8 GB to make 12GB? Do I have to get another 8GB card? Does it have to be the same brand as whats currently in the machine (Which IDK)? 

 

Also, another question:

 

So I got my P50 with a smart card reader thinking it was the same thing as an SD card reader. I turned out to be wrong. Anyway, I was wondering if there's an accessory to fill in the slot while a card is not in there; I don't want dust, particles, etc. getting into what amounts to a whole in the machine.

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Message 2 of 24

Re: Do I need to install RAM in pairs?

Hello,


The new memory module should have the same electrical and timing characteristics as the currently-installed module. 

 

I have only seen memory installed with matched capacity in a ThinkPad P50, so am not sure of the exact behavior if you install two memory modules in different capacities, such as 8GB and 4GB. 

 

It used to be that if you installed memory modules with differing capacities that each memory module would be accessed using a single-channel of bandwidth.  If matching memory modules were installed, access to them would be interleaved, resulting in memory access at twice the bandwidth.

 

Recent Intel chipsets have a technology in them called Flex Mode, which basically means that if you install two memory modules with different capacities, such as 4GB and an 8GB memory  module, that memory in the mataching capacity (the 4GB memory module and the first 4GB of memory on the larger 8GB memory module) would be accessed in dual-channel mode, while the remaining upper 4GB of memory would be accessed in single channel mode.

 

Regards,

 

Aryeh Goretsky

 



I am a volunteer and neither a Lenovo nor a Microsoft employee.

L380 YogaP50 (20EN-*)S230u (3347-4HU)T23 (2648-LU7)T42 (2378-R4U)T43p (2678-H7U)T61p (6459-CTO)W510 (4318-CTO)W530 (2441-4R3)W530 (2441-4R3)X100e (3508-CTO)X120e (0596-CTO)X220 (4286-CTO)X250 (20CM-*)Yoga 370

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Views: 27,661
Message 3 of 24

Re: Do I need to install RAM in pairs?


@Bullshark wrote:

I have an a model I got with 8GB because I wasn't gonna spend 100 bucks more for 16GB. I see that I can buy a RAM card for like 40 bucks. However, does it have to be the exact same brand and/or size? I know the RAM in this thing is DDR4-2133 SODIMM; according to Crucial and Newegg, I can buy another card for 40 bucks or so of the same type of RAM.

 

Can I buy a 4 GB to add onto the 8 GB to make 12GB? Do I have to get another 8GB card? Does it have to be the same brand as whats currently in the machine (Which IDK)?


As was already stated, in order to optimize memory performance so that it operates in "dual channel" mode, you need to have matched pairs of memory sticks installed.  If you have just one stick of the required pair your memory will operate in the less-than-optimal "single channel" mode.

 

So yes, you can add a second 8GB stick of less expensive Crucial etc. memory that has the same timing and latency numbers as the Lenovo-provided Samsung memory stick.  And now you will have a configuration that makes your now 16GB run somewhat faster than your current 8GB runs.

 

Additionally, not only do you need to have "matched pairs" of memory sticks, but you also must insert them into MATCHED PAIRS OF SODIMM SOCKETS in order to obtain the "dual channel" mode behavior.  The P50/P70 have four SODIMM slots for memory sticks, arranged in "matched pairs" of sockets.  There are two hard to get to slots under the keyboard numbered #1 and #3 (which requires the keyboard to be removed in order to access them), and two more easy to access slots on the underside of the laptop numbered #2 and #4 (which simply requires removing the cover on the underside of the laptop by loosening five screws in order to reveal these two "open to the air" slots).

 

When you bought your laptop with just one single stick of 8GB of Lenovo/Samsung memory, it was factory installed in slot #3 (under the keyboard).  If/when you order your own after-market second matching stick of memory you really do want to install it in the second matched pair slot to #3, which is slot #1... i.e. under the keyboard. So the "install surgery" you're going to have to perform in order to achieve the desired 2x8GB=16GB operating in optimal dual-channel mode will require you to go through that process yourself, i.e. removing the keyboard and then inserting the new 8GB stick into the second #1 SODIMM slot.

 

You actually can insert this second stick into one of the two available easy-to-access slots (#2 and #4) on the underside of the laptop and you'll still achieve 2x8GB=16GB memory size.  But that 16GB of memory will be operating in somewhat less-than-optimal single-channel mode.  Only matched pairs (either one pair or two pairs) of two memory sticks installed into the specific matched pairs of SODIMM slots will achieve optimal dual-channel memory performance.

Bullshark
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Location: US
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Message 4 of 24

Re: Do I need to install RAM in pairs?

I just used the command 

wmic MEMORYCHIP

, and found a part number 16ATF1G64HZ-2G1A2. I then Googled it, and found this: there's a review that says:

 

 

"It works great with Lenovo P50 laptop. CPU-Z shows a part number of 16ATF1G64HZ-2G1A2, which is exactly the same as what comes with my laptop. (The memory came with my laptop was branded as Micron instead of Crucial, but they have the same part number)"

 

Does this mean I can buy the Crucial one (Crucial is a brand of Micron) and it'll be as if I bought from the Lenovo website?

 

 

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Posts: 2,089
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Message 5 of 24

Re: Do I need to install RAM in pairs?


@Bullshark wrote:

 

Does this mean I can buy the Crucial one (Crucial is a brand of Micron) and it'll be as if I bought from the Lenovo website


That Crucial 8GB SODIMM card is absolutely compatible with your P50 and the existing 1x8GB=8GB memory from Lenovo (which is probably actually from Samsung).  If you bought memory from Lenovo you'd [probably] get a Samsung card, but the Crucial memory is "guaranteed compatible" and significantly less money.  I myself did exactly the same thing with my P70 that you're planning for your P50... buy minimal 1x8GB from Lenovo with the machine, and buy additional 1x8GB from Crucial.  Works perfectly.

 

But again, I mention that proper installation of your second 1x8GB card should be in the corresponding second SODIMM slot (#1) which is the "paired slot" to the #3 slot where the existing Lenovo 1x8GB card is installed.  And both of these slots are in the under-the-keyboard memory bay (which holds memory slots #1 and #3).  This is where your 1st additional memory stick needs to go in order for you to then be running 2x8gb=16GB in optimal "dual-channel" mode.  So prepare yourself for removing the keyboard in order to get to the second open memory slot #1.

 

If you instead choose to install your additional 1x8GB card in one of the two "easier to get to" memory slots (#2 and #4) on the underside of the laptop (accessed easily simply by removing the bottom cover of the laptop) you will still get your target 2x8GB=16GB total memory size, but it will be operating in the less-than-optimal somewhat slower "single-channel" mode.

 

Nevertheless, the Crucial memory is fine to use.

Bullshark
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Posts: 53
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Location: US
Views: 27,610
Message 6 of 24

Re: Do I need to install RAM in pairs?

is the quality from Crucial as good as from Lenovo directly?

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Message 7 of 24

Re: Do I need to install RAM in pairs?

100% compatible and functionally identical.  Your BIOS will be completely satisfied and will not see any difference.  It's just from Crucial (i.e. Micron, the largest or 2nd-largest memory maker in the world behind Samsung perhaps).

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Message 8 of 24

Re: Do I need to install RAM in pairs?

Hello,

 

I installed 32GB (2×16GB) of Crucial memory into my ThinkPad P50.  The part number for the kit is CT2K16G4SFD8213, which consists of two 16GB memory modules, Crucial P/N CT16G4SFD8213.  Technical specifications for this line of memory modules can be found in this PDF file. 

 

Here's a link to the memory kit on Amazon:  https://www.amazon.com/dp/B015YPB8ME/.  It was a few dollars less last month--you might want to wait to see if the prices goes down.

 

My P50 has only seen light use since I'm still in the process of setting it up, but I have not noted any problems so far from using this memory.

 

Regards,

 

Aryeh Goretsky

 



I am a volunteer and neither a Lenovo nor a Microsoft employee.

L380 YogaP50 (20EN-*)S230u (3347-4HU)T23 (2648-LU7)T42 (2378-R4U)T43p (2678-H7U)T61p (6459-CTO)W510 (4318-CTO)W530 (2441-4R3)W530 (2441-4R3)X100e (3508-CTO)X120e (0596-CTO)X220 (4286-CTO)X250 (20CM-*)Yoga 370

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Bullshark
SCSI Port
Posts: 53
Registered: ‎08-13-2016
Location: US
Views: 27,538
Message 9 of 24

Re: Do I need to install RAM in pairs?

I ran the command wmic MemoryChip, and here's what (see the picture attached):

 

it appears to be in bank 2: does that mean when I order a new chip, it must go in 4 to work well? Thank God if I don't have to take the keyboard out. Getting the bottom cover off was living hell.

 

Also, how is Corsair? I found another 2133 PC-1700 8GB ram card there. Is Corsair better than Crucial? Is this one compatible? Or Kingston? I found 2 8GB ram cards there; which one is the one to get?

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Message 10 of 24

Re: Do I need to install RAM in pairs?

If you took the bottom cover off, then you can see the easy-to-access memory bay already.  This is the one that has paired slots #2 and #4, and they are completely visible.  If you can see the one 8GB factory memory card from Lenovo installed in one of those two slots, then your second 8GB card (no matter what brand or who you buy it from) goes into the other of these two slots.  If both of these completely visible memory slots are currently blank, then you obviously have the 8GB factory memory card from Lenovo installed in one of the two paired slots #1 and #3 under the keyboard.

 

So you yourself can see for yourself right now whether you're going to have to remove the keyboard or not in order to install your after-market second 8GB in the other slot of the pair in which the 8GB factory Lenovo memory card is already installed, so as to achieve dual-channel mode or not.

 

The terminology of "memory bank" or "memory slot" or whatever you want to call it, don't be distracted by terminology.  Just look for yourself, and you'll have your own answer.  WMIC appears to reference the memory slots as "banks", but these don't seem to be numbered the same way as other programs (such as highly recommended CPUZ which you should also have installed and available for your use) identify them.

 

For example, on the desktop PC I'm currently working at I have 2x4GB of memory installed in two of the four DIMM slots (let's just call them slots #1, #2, #3 and #4).  In particular, the two memory cards are in slots #2 and #4.  When I run CPUZ and look at the SPD tab (which shows exactly what memory is installed in each DIMM slot) it tells me I have 4GB in "slot #2" and "slot #4".  But when I run WMIC it tells me I have 4GB in "bank 1" and "bank 3".  Obviously the two programs simply have different terminology, with WMIC referring to "bank 0", "bank 1", "bank 2" and "bank 3".  Clearly it is the same two physical memory slots that hold each 4GB memory card, and it's just program terminology that differs in describing the two occupied slots vs. the two vacant slots.

 

So, back to your story.  My guess is that your discovery through WMIC that you currently have 8GB in "bank 2" (out of bank 0, bank 1, bank 2 and bank 3 which is how WMIC describes a 4-slot machine).  I would predict if you used CPUZ you would see that this 8GB is installed in "slot #3" (one of the two under-the-keyboard paired slots #1 and #3), just as I have said Lenovo does with their factory memory.  If you bought two memory sticks from them they would be in these slots #1 and #3 under the keyboard, and then you would be able to easily install your own additional memory in the easy-to-access two other paired memory slots (#2 and #4) on the underside of the laptop under the bottom cover.

 

So, use your eyes and see if the open two slots in the underside memory bay under the bottom cover are both empty or not.  The rest is obvious.  Also, if you use CPUZ I'll bet that Lenovo memory you say WMIC identifies as being in bank 2, is in "slot #3" according to CPUZ... i.e. under the keyboard.

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