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Sata2 ?

M

mac jones

macrumors 68040
Original poster
Apr 6, 2006
3,257
4
I'm a little confused about the SATA controller (nVidia) in the new Macbooks

It say's in the profiler that it's 3gbps (SATA2) . I took this to mean that it would run at that speed not just support it. (For instance, the last gen. MBP says 1.5Gbps for SATA,with no need to claim the higher spec because most SATA1 controllers support SATA2 drives)

But my Intel X25 is maxing at about 170gbps on the Glassbook and on my desktop the same drive is getting sustained 230Gbps.

These are measured with the same benches (HDtack, HDtune,Xbench)

I'm finding that far too many controllers claim 3gbps speed capability when they aren't. I guess the manufacturers figure they can get away with it cuz nothing will use that sort of bandwidth (not even the velocity raptors)

wrong!

So i'm wondering if this can be fixed by firmware as it's not a small difference in speed.

Note: I'm reading a lot of post saying that Intels X25 calims are exaggerated as they only get the lower limit but this is most certainly due not to Intels false calims but the controller manufacturer's false claims or bad firmware.

I'm posting this here as I was a bit supprised to see the 3gbps spec in the profiler and i hoping that a firmware update could fix this.

(Got to start somewhere )
 
3Gb/s (not 3GB/s) is the max theoretical bandwidth. Real bandwidth is always lower. Same thing happens with wireless networks...Have you ever seen your 802.11n connection hit 600Mb/s, cause I sure haven't. The realistic max of an SATA2 connection is around 300Mb/s.

P.S. I sure hope you're not getting 230Gb/s on your desktop, cause if you are, I wanna know what drive you're using!

P.P.S. It's Velociraptor, not Velocity Raptor. ;)
 
LoneWolf121188 said:
3Gb/s (not 3GB/s) is the max theoretical bandwidth. Real bandwidth is always lower. Same thing happens with wireless networks...Have you ever seen your 802.11n connection hit 600Mb/s, cause I sure haven't. The realistic max of an SATA2 connection is around 300Mb/s.

P.S. I sure hope you're not getting 230Gb/s on your desktop, cause if you are, I wanna know what drive you're using!

P.P.S. It's Velociraptor, not Velocity Raptor. ;)
Click to expand...

It's strange cuz I was a little nervous making this post as it's sort of bizzare that this it is what it is.

It's an Intel X25 SSD and yes it appears to be going this fast. I'm not the only one getting this result (Intels specs,etc)

I don't want to "double post" or repeat myself so I suggest you read my post more carefully.
 
being a notebook drive and using an integrated notebook power and data SATA cable it will probably be slower than using a desktop drive and a separate desktop data SATA cable.
 
richthomas said:
being a notebook drive and using an integrated notebook power and data SATA cable it will probably be slower than using a desktop drive and a separate desktop data SATA cable.
Click to expand...

That's right, I didn't think of that -thanks.

If it's cables there might be a serious problem but I suppose it could be possible to fix this (not that i would want to try)

here's a bench of this

http://i35.tinypic.com/xkwpxz.jpg

Also, I've found someone else with this same issue at the Lenovo forum

quote:

I have one of those new generation SSD drives that is capable of 250MB/s Read 100MB/s write.* Because Lenovo decided to limit the speed of the interface to 1.5Gb/s my drive is running at a fraction of what it is capable of.* On my non-lenovo desktop the same drive runs much faster since it supports 3.0Gb/s SATA II.
*
Lenovo must provide a way to turn 3.0 Gb/s back on.* I understand that at the time the 61 series was engineered decisions were made to save power but that decision is going to come back to haunt Lenovo.* The second generation of SSD drives are going to start shipping very early next year and you are going to have a bunch of irate customers.
*
Just put a setting in the BIOS and be done with it.*
*
I still don't understand how Lenovo never expected SSD speeds to bypass 150 MB/s. It's no secret what Intel and others have been working on for the last year. Especially with the NDA roadmap meetings I'm sure you have with them.*
*
Thanks
 
Whooooooo boy....lets get a few things clarified:

1 MB/s != (that's "does not equal") 1 Mb/s. MB is megabyte. Mb is megabit. There are 8 bits to a byte, therefore there are 8 Mb to 1 MB.

Bandwidth/throughput (that's the speed of the SATA interface...or any method through which data is transferred, ie ethernet, wireless, etc) is measured in bits per second, or in this case, Gb/s.

Read/write speeds are measured in bytes per second, or in this case, MB/s.

The SATA II interface has a max theoretical bandwidth of 3Gb/s. That's 375 MB/s (its actually roughly 357 MB/s, for reasons I won't get into here...see disclaimer at bottom).

According to the pic you posted, your drive is averaging 205.1 MB/s. That's (approximately) 1.64 Gb/s. Therefore, your SATA controller is SATA II, since SATA I has a theoretical maximum of 1.5 Gb/s.

Additionally, you're drive is operating at roughly 57% of the maximum theoretical bandwidth of the SATA II interface. That's pretty damn good.

Finally, an SATA I controller cannot be "updated" via a software update to an SATA II controller (to my knowledge). It's a limitation of the hardware.

Hope that clears a few things up.

Disclaimer: I won't go into MiB vs MB vs Mb...that's way beyond anything I feel like explaining at the moment. Suffice to say the HDD industry can be really annoying sometimes.
 
LoneWolf121188 said:
Whooooooo boy....lets get a few things clarified:

1 MB/s != (that's "does not equal") 1 Mb/s. MB is megabyte. Mb is megabit. There are 8 bits to a byte, therefore there are 8 Mb to 1 MB.

Bandwidth/throughput (that's the speed of the SATA interface...or any method through which data is transferred, ie ethernet, wireless, etc) is measured in bits per second, or in this case, Gb/s.

Read/write speeds are measured in bytes per second, or in this case, MB/s.

The SATA II interface has a max theoretical bandwidth of 3Gb/s. That's 375 MB/s (its actually roughly 357 MB/s, for reasons I won't get into here...see disclaimer at bottom).

According to the pic you posted, your drive is averaging 205.1 MB/s. That's (approximately) 1.64 Gb/s. Therefore, your SATA controller is SATA II, since SATA I has a theoretical maximum of 1.5 Gb/s.

Additionally, you're drive is operating at roughly 57% of the maximum theoretical bandwidth of the SATA II interface. That's pretty damn good.

Finally, an SATA I controller cannot be "updated" via a software update to an SATA II controller (to my knowledge). It's a limitation of the hardware.

Hope that clears a few things up.
Click to expand...

That was from another desktop. Not the notebook. (actually, I was getting better results on another desktop than that particular bench :) )

thanks for all the info.
 
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