Question PCIE to NVME adapter not reaching full speed of pcie 2.0 X4

computer23

Reputable
Oct 25, 2021
18
0
4,510
Hi there, I have installed a sabrent adapter for pcie to nvme in which I have installed a samsung 990 pro, which according to its specs should be reaching the full speeds of pcie 2.0, however, when I run tests on the drive in crystal disk mark, these speeds are not reached, and only reached up to 75-80% of the maximum speeds that pcie 2.0 can give, which is 2000mb/s .I would like to know if there is a solution to this problem, and what could the cause be. The drive is running in pcie 2.0 - pcie 4.0 transfer mode.
Thanks.

Adapter in question:
 
Last edited by a moderator:
Solution
I have installed a samsung 990 pro, which according to its specs should be reaching the full speeds of pcie 2.0, however, when I run tests on the drive in crystal disk mark, these speeds are not reached, and only reached up to 75-80% of the maximum speeds that pcie 2.0 can give, which is 2000mb/s .
PCIE 2.0 x4 mode will give you ~ 1700MB/s bandwidth for NVME drive.
2000MB/s is max theoretical bandwidth for PCIE 2.0 x4. You have to account for PCIE protocol/ encoding overhead also.
I would like to know if there is a solution to this problem, and what could the cause be.
There is no actual problem. It's working as designed.
Want more bandwidth, then upgrade PCIE connection to PCIE 3.0 or PCIE 4.0.
That probably requires a...
I have installed a samsung 990 pro, which according to its specs should be reaching the full speeds of pcie 2.0, however, when I run tests on the drive in crystal disk mark, these speeds are not reached, and only reached up to 75-80% of the maximum speeds that pcie 2.0 can give, which is 2000mb/s .
PCIE 2.0 x4 mode will give you ~ 1700MB/s bandwidth for NVME drive.
2000MB/s is max theoretical bandwidth for PCIE 2.0 x4. You have to account for PCIE protocol/ encoding overhead also.
I would like to know if there is a solution to this problem, and what could the cause be.
There is no actual problem. It's working as designed.
Want more bandwidth, then upgrade PCIE connection to PCIE 3.0 or PCIE 4.0.
That probably requires a new motherboard.
 
Solution

kanewolf

Titan
Moderator
PCIE 2.0 x4 mode will give you ~ 1700MB/s bandwidth for NVME drive.
2000MB/s is max theoretical bandwidth for PCIE 2.0 x4. You have to account for encoding overhead also.

There is no actual problem. It's working as designed.
Want more bandwidth, then upgrade PCIE connection to PCIE 3.0 or PCIE 4.0.
That probably requires a new motherboard.
AND, you won't notice ANY difference. Benchmark numbers might improve, your real world experience won't change because the difference is too small to detect in normal usage.
 

computer23

Reputable
Oct 25, 2021
18
0
4,510
Thanks, it makes sense now.
PCIE 2.0 x4 mode will give you ~ 1700MB/s bandwidth for NVME drive.
2000MB/s is max theoretical bandwidth for PCIE 2.0 x4. You have to account for PCIE protocol/ encoding overhead also.

There is no actual problem. It's working as designed.
Want more bandwidth, then upgrade PCIE connection to PCIE 3.0 or PCIE 4.0.
That probably requires a new motherboard.