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User profile for user: Rodko
Rodko Author
User level: Level 1
15 points

MBP 15" 2018 Port speed tests to EXT SSDs SAMSUNG T7 & T5

Just bought a T5 and T7 samsung SSD 250gb and 500 gb , ran Black magic speed tests thru all 4 ports . USBC .. It gives vastly differing results left two ports than right ports .( 1st port has power )

right no 2 port shows write  491 MB/S  read  525 MB/S 

left no 2 write  39 MB/S  read  40 MB/S  can this be right ???


apple specs for this model MBP read as follows

https://support.apple.com/kb/SP776?locale=en_GB


Charging and Expansion

Four Thunderbolt 3 (USB-C) ports with support for:

  • Charging
  • DisplayPort
  • Thunderbolt (up to 40 Gbps)
  • USB 3.1 Gen 2 (up to 10 Gbps)


is my left side ports 10 x slower than Right side ??

or is this machine popped a keg ? any help would be greatly appreciated

Im astonished ..




MacBook Pro 15”, macOS 10.13

Posted on May 15, 2020 8:12 AM

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User profile for user: HWTech
HWTech
User level: Level 9
60,284 points

Posted on May 15, 2020 3:52 PM

Is anything else plugged into either of the left side ports when you are testing the SSDs? Have you tried turning one end of the USB-C cable upside down when plugging into the laptop? If you are using any adapters or dongles then try using a different one (and a different brand if they are not Apple originals).


Try an SMC reset and a PRAM reset.


Try it while booted into Safe Mode.


It is possible the left side ports are partially defective and limiting the speed of the drives. There is protective safety circuitry on each I/O Board so if this part is defective it could affect both ports on the same side of the laptop. If so, then you will need to have Apple examine the laptop and possibly repair it.

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User profile for user: HWTech
HWTech
User level: Level 9
60,284 points

May 15, 2020 3:52 PM in response to Rodko

Is anything else plugged into either of the left side ports when you are testing the SSDs? Have you tried turning one end of the USB-C cable upside down when plugging into the laptop? If you are using any adapters or dongles then try using a different one (and a different brand if they are not Apple originals).


Try an SMC reset and a PRAM reset.


Try it while booted into Safe Mode.


It is possible the left side ports are partially defective and limiting the speed of the drives. There is protective safety circuitry on each I/O Board so if this part is defective it could affect both ports on the same side of the laptop. If so, then you will need to have Apple examine the laptop and possibly repair it.

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MBP 15" 2018 Port speed tests to EXT SSDs SAMSUNG T7 & T5

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