Although it’s common knowledge that virtually any SSD is going to be a noticeable improvement over a traditional spinning hard drive, they are still a huge amount of variation in speed among different models of SSD’s on the low end. They might advertise speeds of a few hundred megabytes per second, while at the high end, you might see close to 3GB per second.
But here’s a basic rule to remember, just because one SSD purports to give you ten times the speed, doesn’t mean that your computing experience will actually be 10 times more enjoyable. So, let’s take a deeper dive into what the manufacturer provided numbers mean and some other factors that might be more important.
The large impressive numbers that are most often trumpeted by SSD manufacturers are the maximum sequential speeds. Which are how fast a drive can be, if all you’re doing is moving around single large files that stay in one piece on your device. But thing is for most users that simply isn’t how they’re using their systems day to day. Instead, the real advantage of an SSD often comes from how many input/output it can handle. A measure of how many smaller operations that can deal with per second.
So, think about loading up a web page, launching a program or posting a video to social media. None of these everyday activities require huge contiguous blocks of information to be read from or written to your SSD. However, if you’ve got a slow mechanical hard drive, these tasks can take quite a while. This was never more evident than when the first consumer SSDs hit the market using the original SATA protocol. It was capped at about a hundred and fifty megabytes a second.
Although the sequential speeds of these early SSDs weren’t that much faster than hard drives, because they were both up against the same interface limit. They blew mechanical drives out of the water in terms of input/output. Because they didn’t have to wait around for the platter to position itself correctly under the head, before any data could be read or written. Instead, small random areas of the SSD could be accessed nearly instantaneously. Making the system feel much more responsive, even though the speeds on paper weren’t all that impressive.
Unless you’re, often doing large file transfers, input/output are going to be more important. But, don’t stress out too much about those either. Pretty much any good quality modern SSD will be able to handle the kinds of random operations that the average desktop user would throw at them. Unless, they were to come up against some pretty specialized workloads. Most drives are going to list them input/output alongside a particular queue depth or QD, which is basically a measure of the drive’s performance while it has a certain number of tasks that it’s waiting to complete in the background.
If you’re hitting the drive with tons of requests, the queue depth will get longer and longer and the drive will be able to handle more input/output by scheduling them more efficiently. But the thing is that it’s really difficult for even a power user, like a video editor, to push past a queue depth of about eight. So, those gaudy measurements that you’ll see listed on the spec sheet, said queue depth thirty two are essentially meaningless unless you’re running a ton of virtual machines on a single drive.
So then, how many input/output do you actually need at lower more realistic queue debts? The answer is honestly: not all that many. Even a drive that lists 10,000 input/output read at queue depth one can probably give you 30 to 40 megabytes a second of throughput. Which might not sound like much, but considering that we’re talking about random small operations instead of big chunks of data, you’re still probably going to have quite a snappy experience. Newer higher-end SSDs can give you significantly more throughput than that.
Now that’s not to say that modern drives can’t have some important bottlenecks. The really cheap ones for example, that don’t have a dram cache or that use a very poor quality controller can suffer from noticeably worse responsiveness.
I want to change gears a little. Maybe you don’t use your SSD in a PC, but rather as a recording drive for your 4k cinema camera. Now this is where sequential performance is going to matter more. But, take the numbers on the spec sheet with a grain of salt.
SSDs, are made up of billions of tiny cells which can hold between one and four bits each. Drives that hold more bits per cell are cheaper per gigabyte, but they’re also slower. So many consumer drives will reserve a certain number of their cells as a fast cache that will only hold one bit per cell. So what ends up happening is that if you’re moving a large file, the drive is going to hit that reserved cache first at very high speeds. But after a certain amount of time it’s going to get all filled up and the sequential speeds will drop significantly.
Your best bet is to figure out how large the files you need to move around usually are and how quickly you need your file transfers to go. Then, go look up the drives you’re interested in on a reputable review site to see what their actual sustained performances. It should be relatively quick math.
You might find that you could make use of a more expensive nvme drive that can handle well over 1 GB/Second or you might find that a cheaper, SATA SSD will serve you just fine. And if you’re using your computer to game. Odds are a pricey nvme Drive won’t help you much beyond maybe shaving a couple of seconds off your loading times. Because the bottlenecks tend to be elsewhere in the system, whether it’s, CPU, RAM or otherwise, you might be better off just buying a regular SATA Drive and putting your extra cash towards more storage capacity, a better graphics card.