Which factor is more important for HDD performance?

None of those.
The speed is the main factor.
The higher the RPM, the faster HDD would write/read, thus, the performance would be quite bigger no matter if it's SATA II or III, and no matter what's the size of it's cache.
SATA III only matters when you write big files at once (11+GB Blu-Ray movie in one piece, for example), big cache only matters when you copy and write many (at least 10+) different files from one HDD to another.

Truly High Performance HDDs begin with the RPM of 10000 and up, everything that's lower (7200 RPM and lower) is a mainstream HDD.
"10000 RPM SATA II 32 Cache" HDD would perform A LOT better than the "7200 RPM SATA III 64 Cache" HDD.

That was kind of what I've always believed but I've heard that cache size leads to faster boot speed and overall speed increase which is why people were hyping up the use of SSD for caching. I've avoided 10,000 RPM drives because past 250GB they get a bit pricey and I've always figured the faster the heads working means an increased chance of crash.

There are really fast 7200rpm HDD. Honestly, if you want max speed, get a SDD.

Faster than 7200 rpm HDD are a thing of the past, they are have been replaced by SSDs or getting replaced as we speak.

You have two options for HDDs: The Green or 5400 rpm version or the 7200 rpm version, the only factor that should matter to you is GB/$(and reliablity/warranty to a degree), as long as you get that you are good since everything you need speed in you already have the SSD for. If you are really limited in cash and can't afford a cheap 256 GB SSD then get a 7200 rpm HDD, else go for the best GB/$

Pretty much. Having gone from a raptor (loud as hell....old scsi drives say hello) to ssd I don't really see any reason to buy these drives. Especially with a Z77 board you can get a 64gb SSD+ 1.5tb 7200 rpm drive that will be 41*% faster than a raptor. I can't benchmark like anand, but I can give my totally biased own experience and agree with their findings. For everthing else 7200rpm (cache irrelevant) is the way to go. For MASS storage I still use 5900rpm drives. My dvd collection streaming over N doesn't care the least about the speed.


*http://www.anandtech.com/show/4329/intel-z68-chipset-sm...

Also coming back to the enterprise issue, the reason they have the price they have is because of reliability and their MTBF (mean time between failures). Enterprise drives will last in theory MUCH longer!

By the way this all goes out the window for laptops, where I will highly recommend a hybrid drive. The Momentus XT is phenomenal and the difference to a HDD is staggering. No they are not SSD speeds, but man if you need space there is no going back once you had one.

Best answer selected by sharkbyte5150.