yosemite and crucial m550 ssd

Where did you hear that Yosemite will not work with third-party SSDs? Since Apple is always changing the suppliers for their hardware components an OS X cannot really reject a third-party component.

Nothing inHow to install OS X Yosemite on your Mac - Apple Support says anything about component incompatibility.

There have been issues with support/nonsupport for TRIM for some time. I will ask around a little and see what some thoughts on the article might be.

Comments are a mixed bag - some colleagues are using SSD with no TRIM and working very well and getting great speed. Some others are using TRIM Enabler with success with Yosemite. So, the comments are varied but a number of users have 'third-party' SSDs and no issues.

A comment one made, though addressed to external and RAID setups:

SSD TRIM is a command in the SATA specification that tells the SATA SSD to begin the background process of erasing available SSD pages. This process of erasing available pages in SSDs is sometimes known as “garbage collection.” The lack of TRIM support does not necessarily mean that SAS RAID controllers and external storage arrays do not perform garbage collection on their SSDs, it just means that they have to accomplish it a different way. External storage subsystems that have SSDs in them do perform garbage collection, but this step is triggered by the storage system itself and not by specific SATA TRIM requests issued by the host servers.

Given the mean time between failure rates for current generation SSDs, very similar to HDDs, my view would be to not worry about TRIM/noTRIM at this point.

You are very welcome...as we have been discussing there is not an absolute, definitive answer. So the decision really has to be yours. Keep in mind the length of time the machine will be used vs the estimated longevity of the components and does that make it cost-effective for your needs. You will increase the performance a good deal with the SSD, but also taking the memory to the max will add even more performance per dollar. You can check out the max ram that 2008 can take by going to Crucial's site or from OWC, http://www.macsales.com combining the ram and SSD will improve the performance until you decide it is time for a replacement computer.

It really should not be a big problem...though you have upgraded to SSD already, another point is that the Intel and the OWC SSDs use the SandForce controller that does not need or use TRIM. But if you decide to move to Yosemite look at the TRIM Enabler and see if that will meet your needs/

As to Yosemite it is really a matter of do you feel you need it. Does it provide functionality, primarily iOS 8 integration, that you need or want. Otherwise, I still like Mavericks and find it to be a solid Mac OS X version.