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besson3c · Dec 10, 2009, 04:11 AM

Most SSD drives being sold connect to the SATA II interface which tops out at a net 250mb/sec speed. If you want to go higher than that you need to connect the drive to your PCI-E slot, or possibly wait for SATA III to become more common. A SSD connected to a PCI-E slot would allow you to break this barrier, but it would cost a pretty penny.

If you want to go faster than 250mb/sec, wouldn't it be far cheaper to go with an 15k RPM SAS drive or even a 10k RPM SATA drive? If you are looking for speed what is the point of something that is tethered to the SATA II interface?

I understand completely the arguments about SSD drives being more reliable - this makes perfect sense. However, SSD drives are being marketed as being very fast. I can see how they would be faster at some operations, but still, I just don't see the advantage in this department.

Am I missing something? Are there any benchmarks for the SSD drives that are available with some Macs now? I cannot find these posted on Apple's site.

angelmb · Dec 10, 2009, 07:23 AM

SSD drives are being marketed as being very fast.

Cause nobody seems to care about selling them as a zero acoustic contamination item which is not going to perish; 'faster', on the other hand, is just a volatile thing, a dumb marketing first-aid gimmick. No need for PCB dampers, constrained layers dampers or whatever viscoelastic based treatments is more plausible to me than being faster than my computer's current hard drives, but as long as being faster is all people wants, well, that is how they are going to be marketed.

Spheric Harlot · Dec 10, 2009, 07:55 AM

I'd like to see that 15k rpm SATA laptop drive for mobile production.

Can you also make it last somewhat longer when regularly suscepted to vibration - or, failing that, at least make it NOT conk out the second the bass drum hits if the circumstances don't allow for massive padding?

Build me that cheaper than a flash drive and you've got my money when it's time to replace my current 7200 -rpm laptop drive (the fastest currently available, and incidentally almost an order of magnitude slower than the current crop of SSDs).

besson3c · Dec 10, 2009, 12:24 PM

Originally Posted by Spheric Harlot

I'd like to see that 15k rpm SATA laptop drive for mobile production.

Can you also make it last somewhat longer when regularly suscepted to vibration - or, failing that, at least make it NOT conk out the second the bass drum hits if the circumstances don't allow for massive padding?

Build me that cheaper than a flash drive and you've got my money when it's time to replace my current 7200 -rpm laptop drive (the fastest currently available, and incidentally almost an order of magnitude slower than the current crop of SSDs).

I don't think you'll see 15k RPM SATA II drives, SATA III maybe... This is where SAS currently tops out.

I think as far as performance goes SSD drives are good for lots of random access reads/writes since there are no moving parts, but for single large files the performance benefit is not as pronounced.

Spheric Harlot · Dec 10, 2009, 12:37 PM

You think wrong.

Serious Competition: Intel X25-M and Five SSD from OCZ Technology (page 6) - X-bit labs

AnandTech: The SSD Relapse: Understanding and Choosing the Best SSD

In fact, this whole thread is pointless.

There is not really any doubt whatsoever about the advantages of SSDs - not in terms of vibration tolerance, vibration generation, heat generation, access speed, nor transfer speed.

Their rather more expensive, and I wouldn't trust them just yet as even Intel still deals with odd firmware issues that suddenly stifle transfer speeds (as on a recent firmware update), but there's no question about where the market is going for all but a very small segment.

besson3c · Dec 10, 2009, 02:08 PM

For *right now*, the sequential read seems limited by the SATA II interface. This would mean that we need a faster interface for topping 250 mb/sec for single and/or sequential files, no?

I'm not debating the advantages in reliability, access speed, vibration tolerance/generation, or heat...

The Final Dakar · Dec 10, 2009, 02:09 PM

Don't they use less power too?

besson3c · 02:41 PM

Wait, I'm confusing myself... Access speeds would be related to *blocks*, not *files*, right? If so, everything I wrote is wrong

The sequential read speed is important to me because I foresee the greatest potential for saturation on my storage appliance coming from copying large VM images. However, if the access time is for individual blocks...

I guess I still have some reading to do. I know I'm not alone in the confusion over benchmarking/assessing SSD drives. Traditional benchmark tools don't really give the whole picture, SSDs are a whole different animal!

Spheric Harlot · Dec 11, 2009, 04:20 AM

Read the links I posted.

The same criteria for response and throughput apply to SSDs as to regular hard drives. Why should they be any different? It's just that access time is so much faster that it *seems* like the comparison is invalid. In fact, that's the point of it.

Access time is important for tons of little files (like system startup, if I'm not mistaken), while sequential speed is for transferring large chunks of data (like copying virtual machines, tracking audio, or managing media files).

mduell · 02:02 PM

SSD's aren't about sequential transfer speed, they're for IO performance. If you need sequential transfer speed, buy a bunch of disks and stripe them. Spinning disks are pathetically slow for small random reads/writes:

Also they make huge latency improvements, which is important for synchronous operations:

One SSD can give you the performance of a dozen 15k SAS drives if you're doing small, random operations. I'm looking forward to them maturing.

SATA II is not a standard, it was a committee; it doesn't mean anything. Similarly SATA III is not meaningful. Please see the SATA-IO naming guidelines.

besson3c · Dec 11, 2009, 01:52 PM

What are the drives that Apple provides as BTO options on their store anyway? SLC or MLC? Make/model? Their specs page doesn't say more than "solid state drive" unless I'm missing something. There seems to be a pretty wide gap in speeds in SSD options available.

olePigeon · Dec 11, 2009, 01:55 PM

Originally Posted by mduell

SATA II is not a standard, it was a committee; it doesn't mean anything. Similarly SATA III is not meaningful. SATA-IO naming guidelines.

Advertisers say it's a connection type. Advertisers say a MB is 1000K. Apparently it only matters what advertisers think.

mduell · Dec 11, 2009, 02:02 PM

Originally Posted by besson3c

What are the drives that Apple provides as BTO options on their store anyway? SLC or MLC? Make/model? Their specs page doesn't say more than "solid state drive" unless I'm missing something. There seems to be a pretty wide gap in speeds in SSD options available.

Apple uses SSDs with the Samsung controller and MLC flash, which is horrible (see the OCZ Summit benchmarks above).

Don't bother, buy something good aftermarket instead.