Here is an interesting one....
The fusion drive is 2 drives...
A 1tb 5400rpm hitachi drive linked to a 128gb ssd....
Could I replace the 1tb with a 750gb seagate xt hybrid and link it back up with the 128gb apple drive...
Bet this would go like f...
The 8GB of SSD Cache is used for items that are accessed often (like OS files, documents you edit daily, web cache, etc.). These are the same files that OSX will leave on the SSD portion of the Fusion drive. The hard drive only gets items such as MP3's, Movies, Applications you rarely access, etc. etc. Since you aren't accessing these files often, your Seagate Hybrid drive won't have any way of determining are the most accessed files thus rendering SSD Cache almost pointless.
I'm also wondering how the SSD in the Seagate drive determines what should be cached. Does it do it at the Block level or at the file level? Since Fusion works at the Block level, what if the SSD Cache works at the file level? The Hybrid drive may not even see full files and thus completely rendering the SSD Cache useless.
The above is the same reason you don't see Hybrid drives in External hard drives. What would be the point? You don't access the External drive like you do the internal. You use external hard drives for files you do not access often.
Most likely if you even attempted this, you would find little (and most likely no) benefit from this setup other than depriving yourself of 250GB worth of storage since you went from 1TB to 750GB.
Just my .02 worth.
Edit: I'm also going to add that I have a Seagate Momentus XT drive. Frankly I am not impressed by it. It's a stop gap for those who can't afford the relatively high expense of large SSD's (i.e. 512GB) but need that kind of storage. Frankly if you have laptop, get a 120GB SSD and rip out the optical and put a regular 2.5" drive in there. Until Hybrid drives get at least 64GB worth of SSD cache, I see no point.
