I have an upgrade path in mind for a new computer that will be stocked with a 2TB SATA 300 hard disk. This is a choice based on information that SATA 300 is not necessarily faster than SATA 600. The upgrade path in a year time or so would then involve the purchase of an SSD that would contain the operating system and the applications and the HDD would only contain data.
So:
1- Is SATA 300 generally slower than SATA 600?
2- When the HDD is used for data read/write only, is there a substantial overall performance benefit when the O/S runs off an SSD?
Here's what I've found with my own personal experiences.
Most disc drives don't get out of the MB/s R/W range, so changing the amount of GB/s isn't all that big of a deal. Even the two SATA 300 discs that I have in a RAID 0 partition average about 32 MB/s R/W. and my SSD averages at about 220 MB/s, newegg goes up to about 420.
And from what I've learned with my new SSD, there is a very noticeable performance increase. VERY noticeable. Even though my SSD is a lower-end model in SATA 300 (bought from newegg at about $80) it's drastically reduced my boot time (if it's the only disc in the system, I'll get to that later, though) and the load times for most programs are nonexistant, even those on my storage drives (unless they've spun down).
The only problem that I've had with my SSD so far is with booting. The time has increased in my main computer (where it's kept) by a significant amount, however, I'm going to need to blame myself for this one, and Microsoft. You need to have your drives in AHCI mode to enable TRIM support (VERY useful for SSDs) and I want my drives in RAID, dang it! So, I need to go through Microsoft's built-in RAID drivers... Meaning that it has to declare an entire terabyte array every time it boots up.
In short: SSDs; worth every penny. SATA 600; not so much.
That is actually very useful, thank for the outline. So no need to change my plans, in about a year time when the hard disk is well used, but not near capacity, the price point of a 256 GB ssd will also be more attractive.
In the meantime, PCI Express is the new contender for performance and as a result SATA is slated to become obsolete in 2 years time. There is still the price-point issue through, where procurement decisions are based on the GB/$ criterion.