terminater
Contributor
SSD low speed in benchmarks.. How?
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Please check which slot on mobo you have placed the SSD and read your mobo specs to see if the slot speed is reduced due to using other devices in PCI/SATA slots.
Some mobos have these restrictions where the speed is reduced like PCIe 3.0 x2 and not x4 depending on what is placed where...
Some mobos have these restrictions where the speed is reduced like PCIe 3.0 x2 and not x4 depending on what is placed where...
terminater
Contributor
it is placed in M.2 slot as written. Not sure about PCIe 3.0 *2 or X4..
Pic
mobo is H97D3H gigabyte
it is Gen 2X2. still speed is low.?
Pic
mobo is H97D3H gigabyte
it is Gen 2X2. still speed is low.?
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alekhkhanna
Innovator
AFAIK, Gen 2x2 is capable to 1000 mbps only. 2x4 is 2000 mbps, and 3x4 is 4000 mbps.
So for 2x2, these results seems fine.
thegr8anand
Forerunner
H97 is old motherboard i think and gen 2 won't give the speeds you expected. One of the reason i also didn't buy one when I had z97 motherboard. You would not get full speed.
terminater
Contributor
Read speed in test coming 830 MB/sec.. .Even if i consider 10 Gigs./sec , then also seems very low ...
- 1 x M.2 PCIe connector
(Socket 3, M key, type 2242/2260/2280 SATA & PCIe SSD support).. .Mobo spec..
alekhkhanna
Innovator
You can keep going in circles, but for 2 x2 you won't hit more than 1000 mbps theoretical.
nvme io test has always been tricky. seems fio is probably most accurate with perf testing https://fio.readthedocs.io/en/latest/
my wild guess is that the mobo is still using sata protocol instead of nvme.
a quick explenation would be: if you connect the m2 on sata port (pt.3) even though the ssd is nvme, the mobo will still use sata protocol and will be limited by sata controller speeds (in this case 6Gbps) and also there would be a translation overhead from sata protocol to nvme protocol and back and forth.
my wild guess is that the mobo is still using sata protocol instead of nvme.
from the above specs, seems like one m2 port runs on sata and the other runs on pcie, for highest performance you have to connect the ssd to m2 pcie port mentioned in pt.1.
a quick explenation would be: if you connect the m2 on sata port (pt.3) even though the ssd is nvme, the mobo will still use sata protocol and will be limited by sata controller speeds (in this case 6Gbps) and also there would be a translation overhead from sata protocol to nvme protocol and back and forth.
alekhkhanna
Innovator
But wouldn't sata speeds not exceed 600 mbps (max throughout) ? His is at 800 mbps+, so it's clearly at an old gen pcie protocol ?
@terminater Since it's a Samsung drive, use Samsung Magician and it will tell the exact interface being used:
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there is also caching involved. to get exact number you have to use direct io. linux dd equivalent is oflag=direct also you have to do it on raw device to remove file system overhead. as i said it gets really weird really soon.But wouldn't sata speeds not exceed 600 mbps (max throughout) ? His is at 800 mbps+, so it's clearly at an old gen pcie protocol ?
@terminater Since it's a Samsung drive, use Samsung Magician and it will tell the exact interface being used:
You are mistaking BITs and BYTEs here... Your mobo spec is max 10 giga BITs per second (or 1 giga BYTE per second), so your SSD speed test is in the expected range.
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