We've spent a lot of time talking to storage professionals, including some from LSI, who agree that TRIM is beneficial, even when your controller is designed to make the most of free space on an SSD. So, if a SandForce-based drive can see some benefit, so will any other solid-state repository you install. Consequently, it's worth it to get TRIM working, even when Apple tries to keep you from the command artificially.
To what end does TRIM matter? Well, our AJA System Test and DiskTester benchmarks show that the explicit performance gains, even in a synthetic, are pretty small. In the real world, you probably wouldn't notice one way or the other. But sure, turn TRIM on and things speed up a little bit.
More important are the endurance-oriented reasons to keep TRIM turned on. Without the command, your operating system knows when data is deleted, but has no way to tell the SSD's controller. In turn, the SSD keeps moving that information around via garbage collection, unnecessarily programming and erasing the flash memory cells with stale data. This means that, at some point, the SSD will fill up with data, leaving the controller only with over-provisioned flash with which to work. That's seven to 12% of most desktop SSDs, and includes the space for firmware features like bad block replacement.

Ah, Apple. Why must it be a love-hate relationship? Clearly, you make some awesome hardware but your pricing and closed-mindedness is @$$munch. You disable TRIM if one doesn't pay 50 to 75% more for one of your lower-performing (than the typical aftermarket piece) OEM SSDs. Shame on you. Greedy bastards. Get with it or continue to decline. It's good to see in the case of TRIM Apple's @$$munchiness is so mindlessly circumvented. ...and to think I once gave them a bunch of my money. 4" Apple...4"
I installed Windows directly, then performed some magic to install bootcamp drivers later, but the problem was that the EFI in Apple PCs disable AHCI when running Windows.
Now Intel'ss SSD toolbox can still perform TRIM even when it's IDE mode (apparently) but i wasn't sure, so i had to Google a solution.
Currently i have to enter four console commands in a GRUB menu before i can boot into Windows over AHCI, and BootCamp doesn't like it when i do.
It's annoying, because i don't know much Linux, and i have no idea how to enable the GRUM menu or some sort of automated boot script that enters those commands for me.
Commands:
setpci -d 8086:2828 90.b=40
set root=(hd0,1)
chainloader +1
boot
Look at crisso2faces comments above - I see that all the time on drives from multiple manufacturers, not just Samsung. Is seeing a couple extra MB/s in a benchmark worth gambling with possible catastrophic failure because you aren't using the system as designed?
If you bought a Mac without doing research into your own required features, return it. If you're past your 15 days, look at it as a lesson learned. Macs aren't for everyone. Realistically, Macs aren't for anyone aside from people who want the most watered down experience possible, but the pro apps keep people in line for computers that don't really fit their needs.
SSDs attached via PCIe, USB 3.0, FireWire, or Thunderbolt cannot receive the TRIM command. Macs won't even recognize them as SSDs nor would the Mac send them the TRIM command even if it is enabled.
The newest MacBooks now use PCIe SSDs.
SSDs (such as OWC Mercury SSDs with SandForce controllers) have evolved to the point they don't need TRIM - particularly when the SSDs are not attached via SATA? They do their own garbage-collection and optimization.
OWC - in particular - advises against enabling TRIM on their Sandforce controller OWC Mercury SSDs since this increases wear and tear on their SSDs. TRIM adds extra unnecessary writes when the SSD already did this on its own. Enabling TRIM would essentially harm the SSD and shorten its lifespan. http://blog.macsales.com/11051-to-trim-or-not-to-trim-owc-has-the-answer
If modern SSDs need TRIM, they would be in danger of serious performance problems if the SSD was attached via a non-SATA connection such as USB 3.0 or PCIe or Firewire or Thunderbolt. Unless the manufacturer insures their SSD's controller does its own version of TRIM, then they would suffer serious performance problems when attached via non-SATA connection compared to the competition.
This is why I argue that TRIM is currently useless in modern SSDs.