Quick Q: Does the X220 have a SATA 6Gb/s contoller?

[iamdmc]

Or is it only a 3Gb/s controller?

OR is it a 6Gb/s controller that is crippled by Lenovo BIOS/firmware (as was the case with the X61 and the underutilized 3Gb/s controller)

[ZaZ]

Yes, I believe it does, but there's few if any SATA III drive that will fit the 7mm bay without modification.

[iamdmc]

can anyone confirm

FYI - any 9mm height SSD will fit without modification if you don't use the rubber spacers. See my sig for details

[penartur]

Quick A: http://www.lenovoblogs.com/insidethebox ... notebooks/

[iamdmc]

Can you trust an article that references SATA 6Gb/s as "600MB/s"? 6Gb/s = 750MB/s.

I'd love to believe this article, but I'm getting a max of 350MB/s on my Agility 3, and its max should be 550MB/s...

This speed is more in-line with SATA 3Gb/s (375MB/s max)

[penartur]

Can you trust an article that references SATA 6Gb/s as "600MB/s"? 6Gb/s = 750MB/s.

You forget about ECC. And why do you think "SATA 3" is often referred to as "SATA 600", "SATA 2" as "SATA 300" etc?

[iamdmc]

ECC applies to RAM not the SSD

And SATA 6Gb/s is incorrectly referred to as SATA3, yes. The SATA alliance decided to push to call it SATA 6Gb/s instead of SATA3, because that name may be confused with SATA 3Gb/s.

My point still stands. SATA 6Gb/s is NOT 600MB/s. It's not base 10, it's binary! SATA300 and SATA600 are not correct names.

[penartur]

ECC applies to RAM not the SSD

ECC applies to SATA as well. SATA uses some sort of coding, and is sending data in 10-bit packets, each containing 8 bits of actual data and 2 bits of overhead (it is actually some kind of ECC).

[iamdmc]

Saying "there's just overhead" doesn't account for the 2 bits. What is it?

anyway, back to original Q: can anyone confirm 6Gb/s controller (and if it's uncrippled)?

[erik]

I'd love to believe this article, but I'm getting a max of 350MB/s on my Agility 3, and its max should be 550MB/s...

This speed is more in-line with SATA 3Gb/s (375MB/s max)

SATA 3Gb/s tops out at around 265MB/s, not 375.   the fact that you're exceeding 265 is proof that your drive is the issue rather than the controller.

[iamdmc]

Mreally?

Although you didn't mention a source, I trust your advice enough to take you at that. Thanks Erik

[erik]

if it helps, there's no way to limit/cap/cripple a SATA controller at a fractional speed.   the SATA 3Gb/s controllers on T61/X61 systems were put into 1.5Gb/s mode for compatibility reasons.   if the 6Gb/s controller on the X220 were put into 3Gb/s mode then the best you'd see is ~265MB/s max.   since you're clearly exceeding that, there's definitely no cap.

[penartur]

Saying "there's just overhead" doesn't account for the 2 bits. What is it?

I already gave you a link: 8b/10b encoding.
6Gbits/second is the speed on a link layer, 600MBytes/second is the speed on a data layer; additional overhead may apply (such as SATA commands, packet headers etc), decreasing the actual files transfer speed you experience (which may differ depending on how are you using your SSD). But the data speed of SATA3 is 600MBytes/second, and 8b/10b encoding is something done on a link layer and is close to Digital-to-Analog coding.