Aftermarket SSD On A MacBook Pro: TRIM Gets Tested
Benchmark SSD: Samsung 840 Pro
Now, in Upgrade And Benchmark Your 2012 MacBook Air's SSD, we used OWC's Aura Pro 6G + Envoy, which employs a proprietary form factor and second-gen SandForce controller. According to OWC, TRIM isn't necessary in that configuration because SandForce's (now LSI's) DuraWrite technology frees up more space for garbage collection to do its thing.
In truth, though, DuraWrite and TRIM are complementary. User data pending deletion is still freed up TRIM. So, although DuraWrite does successfully aid in improving performance and minimizing write amplification, TRIM further improves this. That's why we used the terminal window to manually switch it back on.
A MacBook Pro gives you a more flexibility, since it'll accept a 2.5" SSD. That opens the door up to drives from any number of vendors based on different controller technologies and firmware versions. Samsung's 840 Pro is a good example. It's one of the fastest drives we've tested, and as a result we're using them in all of our test beds. But the 840 Pro doesn't have DuraWrite technology; Samsung doesn't benefit from compressible data, and its controller employs its own garbage collection algorithms. All the more reason to get TRIM up and running, right?
Although the company recently announced its new 840 EVO, which should replace the vanilla 840 soon, the 840 Pro remains its top-end model. As a reminder, the drive center on the company's own S4LN021X01-8030 NZWD1 controller and employs a 6 Gb/s SATA interface. The 840 and 840 EVO both utilize triple-level-cell NAND, which has implications on endurance and performance. But the Pro family leans on familiar MLC flash manufactured at 21 nm.
Samsung 840 Pro Technical Specifications
| Manufacturer | Samsung |
|---|---|
| Model | 840 Pro |
| Model Number | MZ-7PD256 |
| Form Factor | 2.5" (7 mm) |
| Capacity | 256 GB |
| Price | $240 |
| Controller | MDX |
| Type of Flash | 21 nm MLC Toggle-mode NAND |
| Sequential Read/Write Performance | 540 / 520 MB/s |
| Random Read/Write (4 KB, QD=32) Performance | 100,000 / 90,000 |
| Over-provisioning | 7% |
| Cache | 512 MB |
| Interface | SATA 6Gb/s |
| Accessories | Samsung Magician Software |
| Warranty | Five Years |
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.