Not too long ago, we talked about GDDR5 and GDDR6—more specifically, the differences between the two.
Despite performing the same job, and being, essentially, the “same thing”, there’s a fairly significant difference between the two formats. Following that logic, it makes sense that different drives would possess these differences as well—it’s all memory at the end of the day, after all.
Such is the logic of Samsung’s division between their QVO and EVO line of Solid State Drives (SSDs). At first glance, if one discounts the slightly lower price of the QVO SSDs, they seem identical, especially when considering the comparable write speeds (even when taking into account the substantially more expensive “PRO” line of SSDs). So why the price difference?
Two words: Flash memory.
What is NAND Flash Memory?
All of Samsung’s SSD models use non-volatile NAND (short for Not AND) flash memory, but the architecture of that memory varies between the separate product lines.
NAND memory itself comes in a few different types.
Single-Level cell (SLC): While this NAND format offers the greatest durability out of all the different types, it also tends to be the most expensive.
The “single” part of its denomination indicates how many data bits it stores in each separate memory cell.As the name suggests, SLC flash memory stores one bit of data per memory cell.
Multi-level cell (MLC) stores 2 bits of data per cell, Triple-level cell (TLC) stores 3 bits of data per cell, and Quad-level cell (QLC) stores 4 bits of data per cell. Generally speaking, the fewer data bits assigned to a memory cell, the longer a drive will last.
There also exists 3D NAND cells, which consist of multiple NAND chips within a single drive, leading to much higher storage capacity in a single drive. That said, the higher cost and power consumption of these drives leaves them as specialized devices, completely unfit for consumer use.
Samsung EVO vs QVO
Herein lies the differences between the QVO and EVO product lines. The EVO product line makes use of TLC NAND (3 data bits/cell), while the QVO line makes use of QLC (4 data bits/cell), and the PRO line of products makes use of MLC (2 data bits/cell).
But considering that the cheapest PRO SSD costs a whopping $600 on Amazon (as much as some complete computers these days), it’s fair to say that it’s well out of reach of the average consumer.
At the time of writing, a 2TB QVO SATA drive costs $190 on Amazon, while a 2TB EVO drive costs $230. This price difference between the two product lines is reflective of their lifespan, if not their performance.
Lifespan
The lifespan of drives is measured in terabytes written (TBW), which indicates how many terabytes of data that model of drive can write before beginning to break down. As a point of reference, the aforementioned 2TB QVO drive has a TBW of 720, while the 2TB EVO drive has a TBW of 1200.
As large as this difference may seem, whether or not the average consumer will really feel this difference is a bit of a toss-up. Make no mistake, the difference between 720 TBW and 1200 TBW is huge, but 720 terabytes of data is a LOT of data in its own right.
It’s also worth noting that—unlike HDDs—the working components of SSDs do not degrade when performing read-only tasks. This means that, unless you’re writing hundreds of gigabytes of data per day, even a QVO SSD will likely last around a decade. And, really, if you’re in the business of writing hundreds of gigabytes of data per day, there’s far more specialized devices that you should be using.
Performance
When it comes to performance, it’s a bit of a mixed bag. Both the QVO and EVO drives make use of Samsung’s Intelligent TurboWrite system. TurboWrite allows lower quality drives (in this case, the QLC format of the QVO drives) to simulate the write speeds of drives that are technically superior—like the TLC format of EVO drives.
Because of TurboWrite, both QVO and EVO drives boast write speeds of 520 mbps, and read speeds of 550 mbps—but only to a certain point. After a sustained transfer of ~42 to 72GB of data, TurboWrite runs out of operating memory, meaning that the TLC of EVO drives will perform substantially better.
Capacity
It’s worth noting, though, that QVO drives typically have larger storage capacities than EVO drives. While the smallest EVO drive offers 250GB of storage, QVO drives start at 1TB, going all the way up to an 8TB model. Conversely, the largest EVO model only holds 2TB of data.
Samsung QVO vs EVO: Which Should You Choose?
If you’re looking for an SSD, both the QVO and EVO product lines are a great choice. If trying to decide between the two, consider your use case first.
If you’re simply looking to move from an HDD to an SSD for the purpose of gaming, the QVO drives are more than good enough. The chances that a system meant for gaming will write enough data to kill an SSD are pretty slim—Even after around 3.5 years, my own 3TB system (which holds both an EVO and QVO drive) still has about a terabyte of storage left—meaning I’ve barely even started breaking these drives in.
The EVO drives are really meant for enthusiasts, people who have a little extra money to spend, or the odd use case where that extra bit of longevity is crucial—though this is typically limited to occupational demands. All in all, both product lines are excellent, and one should really consider whether they need the extra lifespan provided by the EVO line.
