While the RAID does function as is, would there be any - improvement or stability bonus to set the jumper to 3Gb/s mode on the SATA-III drive?
Theoretically you gain some performance when the array only has to read data from the fastest drives cache.
However I expect this gain to be minimal, possible not even showing up on benchmarks. Certainly much less then you will notice.
Having said that:
- There is not reason not to jumper for the faster speed. It will not help but it should not hurt either. The only reason to use the slow setting is for backwards compatibility with broken controllers.
- How is your RAID set up? With most RAID configuration you have to wait for multiple drive to read part of the data. If one drive is faster then the other is slower. And you will end waiting on the slower one. (Exception: RAID 1 ).
I wonder [if] "something" might get confused because of the physical disk cache being faster on one than the other. But truly I don't know enough about data storage to answer that.
Nothing should get confused.
Which RAID card are you using? Hardware RAID? Software RAID? How does it handle TLER.
There is a reason why green drives are often a bad choice for RAID, but I heard people successfully used them after applying WDIDLE.