Sata 2 vs Sata 3
With the growing prices of hard drives, I was wondering just how much difference I would notice between a hard drive running in Sata 2 versus one running on the Sata 3. This is just going to be a gaming rig with the ASUS P8Z68-V PRO motherboard. Right now on Amazon I can get a 2Tb Sata 2 HD from WD for 100$ but a 1TB Sata 3 costs 160$ish even on newegg. Would it be wise to even bother with the Sata 3 drives right now? Also, I intend to get an SSD drive within the next month too for the operating system and I am not running RAID currently until prices are more appropriate for storage costs.
Don't bother with SATA 3.0 mechanical drives. If you want to invest money into something that WILL pay dividends, take the $60 you save, add a little, and get yourself an SSD boot drive, like the OCZ Vertex Plus - or much better, the Vertex Agility - mentioned here:
SATA revision 2.0 (SATA 3 Gbit/s)
Second generation SATA interfaces running at 3.0 Gbit/s shipped in high volume by 2010, and were prevalent in all SATA disk drives and most PC and server chipsets. With a native transfer rate of 3.0 Gbit/s, and taking 8b/10b encoding into account, the maximum uncoded transfer rate is 2.4 Gbit/s (300 MB/s). The theoretical burst throughput of SATA 3.0 Gbit/s is roughly double that of SATA revision 1.
All SATA data cables meeting the SATA spec are rated for 3.0 Gbit/s and will handle current mechanical drives without any loss of sustained and burst data transfer performance. However, high-performance flash drives are approaching the SATA 3 Gbit/s transfer rate; this is addressed with the SATA 6 Gbit/s interoperability standard.
SATA revision 3.0 (SATA 6 Gbit/s)
Serial ATA International Organization presented the draft specification of SATA 6 Gbit/s physical layer in July 2008, and ratified its physical layer specification on August 18, 2008. The full 3.0 standard was released on May 27, 2009. It provides peak throughput of about 600 MB/s (Megabytes per second) including the protocol overhead (10b/8b coding with 8 bits to one byte). Solid-state drives have already saturated SATA 3 Gbit/s with 285/275 MB/s max read/write speed and 250 MB/s sustained with the Sandforce 1200 and 1500 controller. SandForce SSD controllers released in 2011 have delivered 500 MB/s read/write rates, and ten channels of fast flash can reach well over 500 MB/s with ONFI drives – a move from SATA 3 Gbit/s to SATA 6 Gbit/s allows such devices to work at their full speed. Full performance from Crucial's C300 SSD similarly require SATA 3.0. Standard hard disks cannot transfer data fast enough to require more than 3 Gbit/s; but they can nevertheless benefit from the later standard as reads from their built-in DRAM cache will be faster across the later interface. According to Seagate "Cache-efficient desktop applications such as gaming, graphics design and digital video editing can experience immediate incremental performance using a SATA 6Gb/s interface". Drives with bigger, faster caches were introduced to benefit from the faster interface.
simple sata2 has 3gbit/s
sata3 has 6 gbit/s
The maximum data transfer rate of a SATA 2 port is 3Gb/s (300MB/s).
The maximum data transfer rate of a SATA 3 port is 6Gb/s (600MB/s).
No single hard drive can spin fast enough to saturate a SATA 2 port.
I don’t know the models of the HDDs you’re looking to buy, but I would be surprised if they had a data transfer rate higher than 136MB/s.
Hard drives may be SATA 3 "compatible", but they are not SATA 3 "capable".