Sata Speeds Degrading

Hey guys,

I have a Latitude E6520 with a Crucial M4 128Gb SSD as the main drive.

I noticed something odd the other day when trying to figure out why my SSD benchmark on AS-SSD has changed so much since I installed it in 2012. In IRST it says my Crucial M4 128Gb SATA transfer rate is 3Gb/s (SATA II). CrystalInfo reports the same. Today I noticed that the transfer rate was 1.5Gb/s (SATA I). It should be running at 6Gb/s (SATA III). Can someone explain why the transfer rate is degrading?

Many thanks,

Ray

 

When you actually run a benchmark what sort of numbers do you get?

 

Original benchmark in 2012:


Yesterday @ 3Gb/s:


Pay no attention to the low 4k-64Thrd speeds on the second screenshot. This is apparently a bug with the M4s firmware that Crucial can't seem to fix. Lots of RMAs and frustration about this.

Then when it dropped to 1.5Gb/s the Seq read/write speeds were 135/100 ish etc. I'm sorry I didn't grab a screenshot at the time.

I think I've solved it though. I upgraded the bios to A19 from A18 and it looks as though the SATA transfer speed is now the full 6Gb/s. IRST/CrystalInfo etc. confirms this. So looks like a bug in A18 Dell bios.

 

Why? I can't say, you need to run a diagnostic. But something is definitely not working right. Maybe a driver issue? But even certain cables can slow down transfer rate.

Again, I can't tell you why, but I experience this when I used a substitute mini USB cable other than the one I got from Gopro.