27 months ago
The SSD Plus is one of Sandisk's "hard drive replacement" SSDs. In other words, it's low end for a SATA 6 Gb/s SSD. It's DRAMless, and the controller is only 4 channel and not that good on top of that, so naturally it tends to perform quite poorly compared to plenty of SSDs with a DRAM cache in many workloads (although boot and program loading times remain largely the same, of course).
While browsing around mindlessly as I usually do, I noticed a short discussion in an article's comments involving a switch to TLC from MLC in the already previously-mediocre SSD Plus.
Yet, Chris Ramseyer (Tom's Hardware) recently got his SSD Pluses with MLC, although with the 120GB model having a different controller version than the 240GB.
So, I decided to look around a little more, and it turns out they did indeed switch to TLC, and now the current drive is the same internally as the Z410.
After some research, it looks like Sandisk SSD Plus has gone through several revisions with different components. The first model is well documented, and used the SM2246 and MLC NAND. Initially, it used the SanDisk 19nm MLC but there are indications that there has also been a version with SM2246 and Sandisk 15nm MLC (we have not been able to confirm that it exists).
The model that we test today, which seems to be the latest, using instead SM2256S with SanDisk 15nm TLC. There are also indications that Sandisk awhile used the Marvell 88SS1074 with 15nm TLC. It has also been found that Marvell checks are better than Silicon Motions and therefore may also be where a certain difference between the models. But to move from 19nm to 15nm MLC TLC's like going from a Crucial BX100 to BX200 and the difference is huge.
For SanDisk defense so it is actually a slight name difference. The old models (those with MLC), the "G25" in its name and the new TLC-based devices instead called "G26". The problem is that almost no stores print what model they sell. There is also no way to see on the box which model you buy. Some online retailers are printing what model it is, but at the same time, it is not safe to store themselves know that they have a slower drive. Say that you had product number when Sandisk launched the first device, and after which it come new devices and you have not changed the number. There is thus a risk that buying a unit in the belief that it is the MLC, but it's TLC.
So... Yeah. The current SSD Plus models with G26 in the end of the model number have different NAND than the previous G25 models. The G26 model seems to have come out in June of 2016, but I decided to post this anyway, in case nobody here was aware of the difference between it and the G25 models.
This is a little off topic, but since the SSD Plus 120/240GB is now the same as the Z410 and I always wanted to say something about these SSDs - Both Jon Coulter (review hyperlinked above) and Chris Ramseyer have a little to say about the Z410/current SSD Plus:
Are the SSD Plus and Z410 viable options in the super low-cost class of SSDs? They are, for the most part, certainly faster than spinning rust buckets, but that's not what we care about; a USB 3.0 stick is faster than a spinning rust bucket so that's not the criteria they need to meet. When compared to other SDDs in the same price range, specifically Phison S10 powered TLC SSDs, both the SSD Plus and Z410 fall pitifully short. We know that SanDisk never intended these two drives to compete for any performance crown, but when they cost the same as others per gigabyte, a certain minimum amount of performance is to be expected. What we got from the all-plastic enclosed SSD Plus and Z410, was metaphorically speaking all-plastic performance.
We believe that at the heart of the matter is the heart of the SSD itself. SMI's SM2256 4-channel controller consistently delivers lackluster performance that only gets worse in the absence of an onboard DRAM cache. We have never been able to recommend an SM2256 controlled SSD and the SSD Plus and Z410 only serve to reinforce our negative view of this particular controller. We have to look no further than our sustained write transfer testing to see exactly why we feel the way we do. When an SSD can't even deliver sustained write performance that's on par with a spinning HDD, we simply cannot overlook that fact.
Running SSD Plus and Z410 as our OS disk was nothing to write home about. The drive provided a decent boot experience and loaded programs in an acceptable manner, however, when multi-tasking, both did a face plant. They both provide a superior user experience to that of a spinning disk unless you are doing something like installing a game or transferring even a moderate amount of data, both of which are common tasks for the majority of users.
The SanDisk Z410 is essentially a point of sale or signage SSD sold in a retail-like package. With so many other low-cost SSDs with DRAM available for the same or slightly higher price, we can't recommend this series for our readers.
And Chris on DRAMless SSDs in general (the SSD Plus 120/240GB and Z410 are DRAMless so I'm throwing it in):
.... For most of us enthusiasts, we shouldn’t even consider DRAMless SSDs with planar NAND. It's true that the drives are faster than a hard disk drive, but when you lean on them with a slightly elevated workload, they can stall, stutter, and deliver a worse user experience than you would get with a spinning mechanical disk.
I agree with the reviewers - the (current or not, really) SSD Plus/Z410 120/240GB is typically overpriced, with better, non-cacheless SSDs normally being the same or slightly higher price such as the PNY CS1311 or SK Hynix SL308 (the SL308 is better than the CS1311 by the way). You will still have the same boot times, program loading times, and as long as you aren't doing much to the SSD at the time, similar access times, but when you can have a much better product for what is practically the same price, why not?