Buy new SSD?

[Nielsenius]

My Mac currently has an OWC Mercury Pro Extreme SATA 2 SSD. It's one of the fastest SATA 2 SSDs out there. But, it only has 115 GB of storage and I find myself running out of room. This spring I'll be buying a new MacBook Pro. Right now my top choice of SSD is a 240 GB Corsair Force Series GT. It uses a Sandforce 2200 controller and a SATA 3 interface. It's nearly identical to the OCZ Vertex 3 and OWC Mercury Pro Extreme 6G, but somewhat cheaper. Is there any reason for me to hold off on buying a new SSD?

 

[Makosuke]

I can think of no reason to hold off other than the fact that next week they will be cheaper, but that's going to be true of every week for the foreseeable future--as with all tech things, buy when you need it.

Just for reference, the reason that the Corsair Force Series GT is cheaper may be that the Corsair GT doesn't handle incompressible data writes very well--the reviews I've seen show the OWC Extreme 6G (for example) being about twice as fast on incompressible-data writes as the Corsair. The Corsair does incompressible-data reads much faster than OWC's Electra, though.

Question: Your sig shows an i7 MBP; I'm assuming that's a 2011 model with working 6G? Assuming so, keep in mind that the optical bay doesn't have 6G SATA on most machines, and often doesn't work well on those that do. (If you don't have a 2011, keep in mind that a 6G SSD will make almost no difference in speed.)

 

[Nielsenius]

I can think of no reason to hold off other than the fact that next week they will be cheaper, but that's going to be true of every week for the foreseeable future--as with all tech things, buy when you need it.

Just for reference, the reason that the Corsair Force Series GT is cheaper may be that the Corsair GT doesn't handle incompressible data writes very well--the reviews I've seen show the OWC Extreme 6G (for example) being about twice as fast on incompressible-data writes as the Corsair. The Corsair does incompressible-data reads much faster than OWC's Electra, though.

Question: Your sig shows an i7 MBP; I'm assuming that's a 2011 model with working 6G? Assuming so, keep in mind that the optical bay doesn't have 6G SATA on most machines, and often doesn't work well on those that do. (If you don't have a 2011, keep in mind that a 6G SSD will make almost no difference in speed.)

Actually, my MacBook Pro is from 2010. So, all of its SATA interfaces are 2.0. My plan was to sell my existing SSD. I can probably get $130 for it. I didn't plan on replacing the optical drive.

I'm interested in what you've said about incompressible data writes. From what I've seen, lower capacity Sandforce SSDs (under 240 GB) have relatively poor incompressible write speeds. It seems, from benchmarks at least, that 240 GB and 480 GB Sandforce SSDs have good incompressible writes (around 300 MB/s). Would you say this is true?

 

[Makosuke]

I can't honestly say I have enough first hand experience to say anything about that one way or the other.

I have a 120GB OWC 6G Extreme on a 6G SATA port, which I initially benchmarked at >480MB/s with AJA disk tester; I'm not sure whether it uses incompressible or compressible data for its test (guessing compressible). A little less than a year of relatively heavy use later with about 45GB remaining free, Aja shows ~410MB/s read and write. Blackmagic tester, which definitely uses incompressible data, I'm seeing about 140MB/s write and >400B/s read. I would take that to mean that it does, indeed, have worse incompressible writes than a larger drive with the same hardware otherwise, but it's also possible it's an artifact of the way the test works (Blackmagic's tester seems kind of erratic, and I'm almost positive I saw much higher numbers a few months ago) or just heavy use of the drive.

In any case, you'll get 250MB/s at absolute best, regardless of what drive you put in the thing; based on that, unless you were planning on carrying the same drive over to a new system in the future, I'd personally go with the Electra--lower price, fast enough performance to saturate the bus.

I personally tend to stick with OWC due to the good warranty (they sure went all-out trying to address the 6G compatibility issues, and even bumped the Extreme to 5 years retroactively after the Electra came out), plus US builds, but they also have tested as VERY good when it comes to automatic garbage collection with an HFS+ volume--much better than, for example, Intel's offerings. Now, it's completely possible (likely even) that the current-generation Sandforce-based drives all handle Mac-format garbage collection equally well--I haven't thus far seen a heavy stress test on other manufacturer drives in terms of how good their garbage collection is--but that gave me a good feeling about them from the start.