05-23-2019 06:38 PM
Yoga 730-15IKB Laptop (ideapad) Machine Type:81CU
I used the Crucial.com scanner that scans your machine and recommends compatible memory for my laptop. It suggested the following:
Crucial 8GB Single DDR4 2400 MT/s (PC4-19200) DR x8 SODIMM 260-Pin Memory - CT8G4SFD824A
On paper and by the specs of the stick of RAM it should be more than capable of working in my machine, however when the stick is inserted it lowers the overall system ram speed to 2133mhz instead of 2400mhz which is not acceptable. This was verified in task manager, as well as CPU-Z and HWINFO programs.
I'm not saying this is Lenovo's fault, or Crucials for that matter, and I have opened a case with Crucial to get that stick of memory removed from the suggested list if it cannot meet the same speeds as the built in 8GB of system RAM that is soldered on the motherboard.
Are there any other dual-ranked RAM sticks that are compatible? I'm currently sifting through the document of RAM that's compatible on Lenovo's site and maybe I'll get lucky but there's a lot of suggestions there for alternate memory that will work.
I wonder if this is something Lenovo could fix via a BIOS update?
Are there any other users out there that were able to get a 8GB module to run at 2400mhz? If so I'd love to hear what model of memory you used. Thanks!
05-23-2019 08:47 PM
Either the RAM soldered to the board is 2133MHz or the new SODIMM is 2133MHz, because the system will clock down to the slowest RAM installed in the System.
Note: The Memory Speed displayed by HWInfo wiil be shown as half its speed (1200 for 2400MHz or 1066 for 2133Mhz) because your RAM is Double Data Rate (DDR).
I have used that same Crucial SODIMM myself, and ran at 2400Mhz, but those were a matched pair.
Crucial has excellent support, so if their SODIMM is the problem I am sure they will take care of it.
05-23-2019 09:33 PM
HWIFNO ran on the built in RAM Reports:
Memory Device -------------------------------------------------------------
Total Width: 64 bits
Data Width: 64 bits
Device Size: 8192 MBytes
Device Form Factor: SODIMM
Device Locator: ChannelA-DIMM0
Bank Locator: BANK 0
Device Type: DDR4
Device Type Detail: Synchronous
Memory Speed: 2400 MHz
Manufacturer: SK Hynix
Serial Number: 00000000
Part Number: HMAA51S6AMR6N-UH
Asset Tag: 9876543210
Total Memory Size: 8 GBytes
Total Memory Size [MB]: 8192
[Current Performance Settings]
Maximum Supported Memory Clock: 1200.0 MHz
Current Memory Clock: 1196.8 MHz
Current Timing (tCAS-tRCD-tRP-tRAS): 17-17-17-39
Memory Runs At: Single-Channel
Command Rate: 2T
Read to Read Delay (tRD_RD) Same Rank: 6T
Read to Read Delay (tRD_RD) Different Rank: 4T
Read to Read Delay (tRD_RD) Different DIMM: 7T
Write to Write Delay (tWR_WR) Same Rank: 6T
Write to Write Delay (tWR_WR) Different Rank: 4T
Write to Write Delay (tWR_WR) Different DIMM: 7T
Read to Write Delay (tRD_WR) Same Rank: 9T
Read to Write Delay (tRD_WR) Different Rank: 9T
Read to Write Delay (tRD_WR) Different DIMM: 11T
Write to Read Delay (tWR_RD) Same Rank (tWTR): 30T
Write to Read Delay (tWR_RD) Different Rank: 24T
Write to Read Delay (tWR_RD) Different DIMM: 6T
RAS# to RAS# Delay (tRRD): 6T
Refresh Cycle Time (tRFC): 420T
Four Activate Window (tFAW): 26T
05-23-2019 11:09 PM - edited 05-23-2019 11:13 PM
That shows that the RAM is running at 1196.8 MHz (Current Memory Clock: 1196.8 MHz), which in DDR terms is 2,393.6 MHz, so that is about what should be expected from 2400MHz RAM. IF it clocks down when you insert the RAM from Crucial, then you need to open a ticket with Crucial, becuase it sounds like they shipped you 2133MHz RAM.
What does the HWInfo report say is the Part Number: and Maximum Supported Memory Clock: of the Crucial RAM When installed?
05-23-2019 11:29 PM
It reports it's maximum clock of 2400Mhz, I will try a stick in another laptop to see if it works at 2400 there, I don't think it's the wrong stick as it identifies it's part number correctly.
05-23-2019 11:56 PM
Very strange. Not sure why it would clock down then. I have always had good luck with Crucial RAM in the past, so I doubt that it is the problem, so it could be some quirk with the memory controller on that system. Very odd indeed.
Best of luck,
05-31-2019 12:15 PM
So I've since purchased a stick of Samsung 8GB 1Rx8 PC4-2666V Laptop Memory Ram M471A1K43CB1-CTD
and it runs at full 2400mhz speed as expected. So going to return the other stick of memory, obviously Crucial needs to remove it from the list of suggested memory for this laptop.