Just curious about the downsides to getting the fusion drive?
Anything related to bootcamp, or splitting them up?
There were some issues with bootcamp and 3TB drives but that got cleared up with 10.8.3.
The GUI tool doesn't really want you to split them up. Primarily because you would nominally need a completely different and external OS to boot off of to completely "dismantle" the Fusion drive. For most users that would be a mistake in the similar way as trying to erase/reformat the drive/volume you have currently booted onto.
Again if move to 10.8.3 with updated tools it shouldn't be a major issue.
I would be interested in having a blade SSD and a HD in there, but I don't like logical drives.
Drive partitioning creates logical drives. It isn't the logical that is an issue. There is a small risk increase in that your single logical drive is spread out over two drives. If either one of those two drives fail there is no redundancy covering the whole volume in what CoreStorage provides in the "Fusion Drive".
However, even single drives need back-ups. This is really not that much different. There could be a difference in restore times if the SSD fails but the HDD doesn't. With Fusion you'd need to restore it all. If the data was split into two volumes than only the SSD's worth would need a restore. If it is an addtion couple 100 GB it isn't a major difference unless have nothing else to do but watch the restore process take place.
I read you can't format using disk utility if you split up a fusion drive.
If you completely wipe the disks ( not the volumes ) clean then there shouldn't be a problem. Folks trying to cherry pick which partitions they are going to save or not probably and cannot use the command line tools probably should just stick with what they have.
There is a small gap between what the GUI tools can do and what the command line tools can do.
Also, does the logical processing of the fusion drive take up CPU usage?
Not that much more than the file system overhead that already incur. SSD drives have logical mapping duties to do that are above and beyond what CoreStorage does and they are "tiny" CPUs compared to what is inside an iMac.
If the Fusion is fairly accurate with moving "hot" blocks to the SSD you'll save far more time than have to "pay" for the minor overhead.
Fusion moves data around when there are gaps in disk activity. That tends to align with gaps in CPU activity also.
I have a 240gb OWC SSD, and currently an iMac with a 1TB drive inside.
Technically you could "roll your own" if you wanted to with what you already have with the SSD in an external drive. There is a risk is accidently unplug the SSD from the machine but
However, if you intent is to chop the Fusion drive appart because "logical bad" then you don't need one. You already have an SSD. Trying to stuff that SSD inside the iMac isn't really necessary.
Unfortunately, OWC doesn't have a dual HD kit yet,
dual HD kit? Something like pack two 2.5" drives into space for a 3.5" drive? Not sure that would be a good idea for Fusion inside an iMac.
and there are no blade-to-SATA connectors that I know of.
There are power issues there also. Technically the blade is a mSATA derivative in form factor but if going to "olug in" a 2.5" drive into a blade's connection that will run into issues.
More likely is that eventually there will be 3rd party blades that can plug into an iMac's connectors. They exist for the MBA and rMBA ... not reason they won't eventually pop up for the iMacs too once there is some demand for opening/closing them with upgrades included.
