TRIM enablement can aid the performance of some third-party SSD units in a system. However, as we work with larger and larger files and come to depend on external storage whether it’s USB or Firewire attached or high-capacity RAID solutions it becomes even more important to choose SSD that doesn’t depend on TRIM.

Apple TRIM Support Only Aids SSD that Needs a Crutch

Lawrence O’Connor | Other World Computing


Recently, I was on a conference panel with several independent filmmakers. One of them noted that he uses SSD in his shoots because they deliver the high-speed performance he needs in his work, are easy to use, easy to manage and rugged.

He said he had gotten into the habit of using a certain firm’s drives (not OWC’s) only five times before they were replaced and used for archiving.  His reason was they seemed to slow down over time and for him, time is money.

He was hoping Apple’s recent release of Trimforce with Apple’s OS X 10.10.4 update would alleviate the problem, giving him more cycle time with his drives.  I reminded him that TRIM support only works for drives in the computer.  External drives connected via USB or Firewire as well as hardware RAID arrays are not supported.  

The command line utility enables TRIM on internal third-party SSDs without having to hack Apple KEXT, an OS driver.   

Following the panel discussion, I spent some time with the filmmaker explaining why TRIM is really a non-issue with OWC’s SSD long-term speed and performance as well as why it is prudent to use SSD solutions – especially for external storage - that don’t depend on TRIM to deliver optimum long-term performance.  

When our devices were first introduced more than five years ago, we wanted a solution that solved the problems at the SSD controller level so “work around” added steps aren’t required.

Choosing DuraWrite technology negates the need for SSD TRIM. It simply isn’t needed!

In retrospect, our two-year delay in introducing SSD until we found controller technology that eliminates the need for TRIM was one of the best decisions we ever made for our customers.

Brief Overview of TRIM

Before you can appreciate this, it’s important to understand what TRIM does for most SSDs.

Left unchecked, the performance of the SSD will deteriorate with use because of the awkward way solid state drives overwrite to areas that already contain data.

When you first begin using a new SSD, files are copied to a fresh blank space and the SSD writes the data directly at full speed. When you delete this file, it isn’t instantly removed from the SSD but the OS simply marks the space taken up by the file as “not in use.”

When the OS requires more space, it simply overwrites the “not in use” zone. With hard drives, this is done in a single step. Solid state dives must first erase the data in that space before it can record new data and the two-step process slows performance.

Added to this is the fact that SSDs can only delete data in 512KB blocks, which further slows down the overwrite process.  

To solve the problem, engineers developed TRIM.

With TRIM, when you delete a file from the SSD, the OS will still mark the file space as “not in use” but it also sends a TRIM command to wipe the marked space clean so the SSD can write new data in that space directly as though it had never been previously used.

This complex routine is called garbage collection, which keeps as large a reserve of empty blocks ready for writing as possible.  

It is actually somewhat of a misnomer because good pages are “collected.” Working in the background so it doesn’t slow production workflow, it involves searching through the inventory of written pages for pages that have been marked as “stale,” then duplicates good pages to new blocks and the old block is erased and marked ready to use.  

Source – Eisen Video Production


TRIM for Your Mac

The vast majority of non-OWC SSDs are very dependent on OS side TRIM to manage where the free space is on the NAND.   

However, with the OS X 10.10.4 update, Apple added a command line utility (Trimforce) that can be used to enable TRIM on these third-party SSDs without having to download and hack the system to allow a work around.

If you use one of these drives in your system, you should enable TRIM by typing "sudo Trimforce enable" into the Terminal window.

The first thing you encounter is a less than friendly warning. Noting that each SSD implements TRIM in a different way, sometimes in ways you’d least expect.  

     Source – Ars Technica

If the warning gives you concern about using Trimforce and you have a non-OWC SSD, you should know that TRIM is never a requirement.

Drives that do not use DuraWrite technology-based controllers should still consider using it because it will still provide some performance improvement when used for a prolonged period.  

The TRIM command provides a bridge from the file and block levels so the OS can tell the SSD that it is deleting files, making the SSD’s garbage collection more efficient.  

This helps make your SSD performance almost as good as new in your system.

Enhanced Beyond Trim

While SSDs that use controllers that employ DuraWrite technology do take TRIM commands from the OS, real world tests have shown the drives not only operate just fine without TRIM but there is also no deterioration of performance or increase in NAND wear/write amplification.

A 240GB Mercury Electra 6G used in a MacBookPro9, 1 2.3 GHz i7 with processor-intensive applications after a number of months of continuous use shows performance has not deteriorated even without Trimforce being enabled because of advanced DuraWrite controller technology.


At best, TRIM is a weak solution for enhancing the performance and life of the SSD. This was the primary reason OWC chose controller technology – which while slightly more expensive, isn’t dependent on TRIM.

The controller processor improves SSD performance and reliability and significantly reduces write amplification – the process of data being moved from block to block.

You can calculate this by taking the total amount of data written and dividing it by the actual size of the file.

For example, a 2.0MB file is written to the SSD. Through garbage collection, it had parts of the file rewritten around the SSD totaling 5.0MB of data moved. The write amplification would be expressed as 2.5x.

The technology compresses files written to the SSD without distorting or losing any of the content, which is especially important in film production because it results in a write amplification of less than 1.0x

File compression means less data is written to the SSD, increasing performance, reducing drive wear and making garbage collection more efficient. Everything that the user needs for optimum performance is built into the controller technology.  

It’s one of the reasons earlier Macs feel and act like brand new systems when enhanced SSDs are installed to extend the system’s use life.

For example, one review organization ran benchmark and SSD performance tests and found it “disturbing” that while the SSDs didn’t excel in typical benchmarks, they “felt” faster and seemed to get the work done faster.  

In fact, they actually are faster in real use across a broader in-use workload!  


But Wait, There’s More

While the OWC SSD provides consistent performance in the real world, we’re often asked why they are smaller than other units that are available (240GB vs. 256GB).

Since their introduction, the SSDs have always included an important over-provisioning feature where a portion of the drive’s total capacity is reserved for performance and maintenance tasks.

The majority of the drives have seven percent over provisioned capacity.  

This free reserved space ensures that the SSD has the room necessary to adequately perform garbage collection so the drive won’t slow down--even when you have filled it to capacity.  


One More Thing

While the lack of TRIM support has never affected the use/performance of OWC SSDs, I think the addition of Trimforce to the latest OS update is a real service to Mac users because it enables them to have a wider choice of solutions for their systems and applications.

Increasingly, power and creative users such as filmmakers want to use SSD not just in their system but also in their cameras, such as those manufactured by Blackmagic Design. In addition, they need portable external drives and high-capacity RAID systems that provide high-speed, high-performance, rugged storage.

Drives that rely on TRIM will not only operate more slowly over time in some load situations, they will also operate with reduced wear-leveling efficiency.

The TRIM-reliant drive will experience much higher write amplification (how many times the data has to be rewritten to complete a single write) which means more wear on a specific NAND location.  

Minimizing Write Amplification and maintaining good wear leveling whether in your Mac or in an external RAID system is critical to the life of an SSD.

TRIM can provide some benefits when used by SSD installed in your desktop or laptop system but for the growing demand for added external storage Trimforce – or any third-party enablers – do not address issues for storage units that are attached with USB, Firewire or Thunderbolt.  

During my discussion with the filmmaker regarding the SSD he uses in his Mac and camera, he asked if enabling TRIM would provide added performance or would there be issues.

I noted that our tests showed there were no issues in using Trimforce or any third-party enablers.  

I added that one customer had contacted our support team saying he had enabled Trimforce but found that the OWC self maintenance was superior to using TRIM, so he had disabled it.  

SSD – a system upgrade replacing an HD or DVD player – may look the same from different manufacturers.  However, there are unseen differences including the choice of NAND for each performance profile, the controller processor, DuraWrite technology, over provisioning and garbage collection that make important in-use differences that can make a Mac feel brand new.

TRIM enablement can aid the performance of some third-party SSD units in a system.  However, as we work with larger and larger files and come to depend on external storage whether it’s USB or Firewire attached or high-capacity RAID solutions it becomes even more important to choose SSD that doesn’t depend on TRIM.   


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