Dell Inspiron 7570 2.5" SATA SSD speed drops from 6 GB/s to 3 GB/s

[JustaGeek]

(Hi, I've been a member for many years, but couldn't sign in to my old account - perhaps because I have been absent for a few years (JustaGeek))

I have finally been able to change my password and log in to my account. I still have to figure out how to change my signature from years ago.

I have a Dell Inspiron 7570 laptop, and it came with 1TB hybrid drive.

I replaced it with Samsung 960 EVO M.2 250GB NVMe PCI-Express 3.0 x4 Internal Drive, and the write/read speeds are about 1,500/3,000 MB/s - fantastic.

Since the laptop is equipped with the NVidia GTX 940MX 4GB DDR5 video card, I decided to add an ADATA Ultimate SU650 2.5" 480GB SATA III 3D NAND Internal Solid State Drive for storage of games (I also own Alienware 17R4 w/ GTX 1070 and i7-7820HK) in place of slow 1TB Seagate that came with the laptop.

I noticed that the 6 GB/s SATA III connection drops to SATA II 3 GB/s, and in speed tests I am getting about 280 MB/s read/write speeds, nowhere near the advertised 500 MB/s or so.

I am not overly concerned, as it is just a storage drive, and the real world difference is most likely unnoticeable, but I am wondering why it happens?

Is it because the PCIe lanes are taken by the video card and the 4x NVMe drive? Is it the laptop power saving system? Is it the ADATA SSD controller? Is it the AHCI Windows 10 system deciding the connection speeds?

I would appreciate if someone could comment on this issue. Thanks in advance!

 

[VirtualLarry]

SATA6G takes more power than a SATAII connection; some laptops throttle the connection speed down for that purpose, even on chipsets / SoCs that support SATA6G natively.

I don't know if that's the reason here, however.

It could be interface CRC or I/O errors, causing Windows to throttle down the connection speed as well.

 

[JustaGeek]

SATA6G takes more power than a SATAII connection; some laptops throttle the connection speed down for that purpose, even on chipsets / SoCs that support SATA6G natively.

I don't know if that's the reason here, however.

It could be interface CRC or I/O errors, causing Windows to throttle down the connection speed as well.

I suspect that that is a reason, as the connection speed drops when testing the speed with Samsung Magician or AS SSD Benchmark, or playing a game, like Sniper Elite 4.

Thank you, Larry.