The performance payback in all areas from establishing a Boot Drive -- with only System Library, Applications, and the hidden unix files including Paging/Swap is MUCH larger than the small increment (mostly in Application launch times) from having the boot drive on an SSD. Save your money and set up a Boot Drive, if you do not already have one.
Size of the SSD
What you expect to achieve
What you have now
For $145 Intel SSD 330 120GB will get you into SSD
You should shop and research brands but most any model today is fine, I think most issues with firmware and compatibility are behind us.
For $150 you could also get 200MB/sec WD 10K VR 250GB SATA3/6G 64MB Cache / $200 for 500GB model, or 1.5TB WD Black
Too small and the write speed is not going to be any better than a mechanical drive in most cases.
10K and you have 3.4ms seeks, 7.2k drives and that is 8-12ms. SSD and 0.1ms
The OS does do a lot of small random I/Os and constant seeks - both to system and also to user home library - so I keep my library on SSD and put everything else on another drive.
SSD + 10K VR + 2TB WD Black is a win-win for most.
A 240GB SSD has more channels (16) to feed the system than a 60GB SSD (4)
Ever since 10.2.2 you could put home folder on another volume.
This is probably one of the easy to follow and best on how to.
You can find a lot on upgrades on MPG:
http://macperformanceguide.com/ Blog and index
Is the aim to save money? I wasn't but the WD 10K VR gives you more storage and nearly as good performance.
Even a WD 1TB is $129 and not much less than the Intel SSD 330 - there you just use short partition and use 1/3 of the drive and get 125MB.sec from standard drive.
And those 10K drives are impossible to kill and don't wear or degrate.
The idea is to use system drive and keep it to system only, though a small 1GB home library is a good fit on SSD for performance.
Thanks but I'm still confused. What is it about a WD 10K VR that makes it "impossible to kill"?
Isn't it this one: http://wdc.com/en/products/products.aspx?id=20
Where can you get it for $129? The cheapest price I can find is $250.
Is the aim to save money?
No, that's what Grant implied so it's a question for him.
Some folks buy themselves an SSD thinking they are going to get a great a performance boost. But the boost they get by only adding an SSD is that Applications launch faster, and not much else.
If you want a bigger boost, and a boost across the board, move the user files off, leaving only System, Applications, Library, and the hidden unix files behind on the Boot Drive. Mac OS X is hugely over-configured on main memory. It is incessantly going back to the Boot Drive for a little of this, a little of that, and it moves the drive heads away from the data files you want to be reading and writing. Once you are not moving the heads away from your data to pick up system stuff all the time, your data drive will get faster.
The big payback is using a Boot drive. An incremental improvement is using an especially fast spinning drive like a VelociRaptor 10K for your Boot Drive. An additional incremental improvement is using an SSD for your Boot drive.
If you just add an SSD, but do not segregate the System, etc on its own drive, you pay top dollar for launching Applications faster. A big disappointment.
John- you understand perfectly.
I used to use 10K and 15K SCSI drives as boot drives, because they were the fastest drives available. Today's "regular" SATA drives have similar access times, but much faster transfer rates because the data is much denser. The big change in the last five years is perpendicular magnetic regions (which increased data density). SATA just came along for the ride.
You can use a 10K Velociraptor drive to go even faster, but the price difference between them and SSDs is shrinking as SSDs come down in price.
I remember back in the day when you had a slow computer and the local PCWorld said, 'Ah, you need more RAM'. I maxxed out the RAM and got the box home but hardly noticed any improvement. Very disappointing.
I remember also hearing all of the hype about SSDs. I wasn't sold so rather than sinking a fortune I bought a little 40, yes 40GB OWC model. Soon after I upgraded to a 120GB Corsair Force 3 from eBuyer.
An SSD is categorically the best money I have ever spent on a computer upgrade! By quite some margin.