Slow SSD to SSD transfer speeds?

[Kaiju]

C: OS drive Crucial M500 120GB Reads:500mb Write 100mb?
E: Crucial MX500 1TB Reads 550mb Write 500mb

Tested using CrystalDiskMark.

When I transfer (5GB file) from C to E, the speed is around 450mb. All good.

When I transfer (5GB files) from E to C, the speed drops to 50mb?

When I transfer the file from either C or E, the speeds are around 100mb to mechanical drives, so the transfer from 2 SSD's is weird.

Both drives are on the same SATA controller but I've tried using a different controller and still the slow transfer speeds.

AHCI is enabled, write cache is enabled on both drives. Windows 10. Drivers/firmware all up to date. All drives are healthy using CrystalDiskinfo and Crucial Storage Executive.

 

[Kaiju]

My OS drive has over 50% free space and now the transfers from my MX500 are under 10mb.

I don't get that as when I transfer from my WD green drive (mechanical), the speed is around 50mb?

How is this possible?

 

[Kaiju]

When transferring large files, it will start at 400mb, then drop to less than 10mb, then go back up to 200mb and drop again.

Is that normal?

With files that are 1gb or less, it can maintain around 400mb transfer speeds.

 

[Kaiju]

Try it with AV disabled.

Try booting into a Linux Mint live USB install and run tests in there.

Install Crucial Storage Executive and check for firmware updates for the Crucial.

Try a new SATA cable.

Good advice but I think it's just the M500 has degraded. It's over 6 years old MLC tech. Userbench has writes at 140mb which is similarly to what I am getting on Crystaldisk.

I'll get a new MX500 and let you guys know.

 

[Kaiju]

I just put in a MX500 250GB drive and write speeds are around 500mb sustained now. So it was basically my OS drive was old tech.