@Neurobear, this is a bit off topic but highly relevant if you bought a SSD that needs trim support such as the Samsung 840 Evo or any other Samsung drive for that matter. Hope it's helpful to you or some other reader. Personally I've had to buy a new drive after deciding on Yosemite given my penchant for security and a preference for headaches free SSDs.
3rd party SSDs for the most part DO NOT have trim support in Yosemite without kext signing security tradeoffs. Apple changes kext signing in OS X 10.10 such that kext singing must be disabled to use applications like Trim Enabler for trim support. So, for Yosemite, reduced security or an OWC SSD with Sandforce are only choices as of now.
Yosemite kills third-party SSD support. Trim kext is altered in Yosemite. This is not relevant if you're using an Apple installed SSD or Sandforce SSD such as OWC's. If you're using a DIY SSD, Trim support is tricky in Yosemite because of recent modifications to kext security management that affects Trim support. More about Trim Enabler for Mac.
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About Trim in Yosemite In OS X 10.10 (Yosemite),
Apple has introduced a new security requirement called kext signing. (A kext is
a kernel extension, or a driver, in Mac OS X)
Kext signing basically works by checking if all the drivers in the
system are unaltered by a third party, or approved by Apple. If they
have been modified, Yosemite will no longer load the driver. This is a
means of enforcing security, but also a way for Apple to control what
hardware that third party developers can release OS X support for.
Since Trim Enabler works by unlocking the Trim driver for 3rd party
SSD’s, this security setting prevents Trim Enabler to enable Trim on
Yosemite.
To continue to use Trim Enabler and continue to get Trim for your
third party SSD, you first need to disable the kext signing security
setting.
It is important to note that the kext-signing setting is global, if
you disable it you should be careful to only install system drivers
from sources that you trust.
Another option, as some drives work without Trim enabled: ZDNet on issues with Trim in Yosemite.
Good Luck!