The Toshiba/Kioxia BG4 1TB SSD Review: A Look At Your Next Laptop's SSD
by Billy Tallis on October 18, 2019 11:30 AM ESTConclusion
The Toshiba/Kioxia BG4 is a rather specialized SSD, intended for thin and light systems that need to maximize battery life and conserve internal volume. It's an OEM-only product that isn't in direct competition with most retail SSDs, which are unfortunately most of what we have to compare against the BG4. But the BG4 isn't an obscure low-volume part; it's being used in flagship models by some of the top notebook OEMs. So even though it will be hard to buy an individual BG4 SSD, it's not hard to find it in the field. With trend-setting OEMs moving to smaller SSD form factors, the BG4 is part of a growing market segment.
Looking purely at performance, the BG4 is nothing special. It meets our expectations for an entry-level NVMe SSD in a largely post-SATA market, but doesn't raise the bar much. Peak performance isn't as high as some entry-level drives, but the worst-case performance from the BG4 is typically not as bad as from many entry-level drives. The BG4 is a clear improvement from the previous-generation BG3 (OEM) and RC100 (retail) for performance, but those older drives were definitely on the slow side even at release.
To cut costs and save space, the BG4 is a DRAMless SSD that relies on the NVMe Host Memory Buffer (HMB) feature to help with the performance problems a DRAMless design usually brings. HMB doesn't completely eliminate the downsides of a DRAMless SSD, but it means that the worst-case performance only shows up in corner cases that are not relevant to typical client usage patterns.
To see what really makes the BG4 special, we have to focus on size and power consumption. The former is pretty much self-explanatory, as the BG4 puts a 1TB SSD on a removable card barely larger than a postage stamp. Meanwhile in terms of power consumption, the BG4's small physical size requires it to strictly limit peak power consumption, and that holds back performance on some tests. But its performance per Watt is usually excellent. The BG4 sets numerous records on our efficiency scores, and some of those records are far better than anything we've previously tested.
When we tested Toshiba's XG5 and XG6 high-end client NVMe SSDs, we thought that they deserved retail versions. They offer good performance and did so with power efficiency that no retail NVMe drives at the time could match. The BG4 is probably better off staying as an OEM-only product. Its greatest strengths are simply not that important to most buyers of retail NVMe drives. The systems that really need the low power and small size of the BG4 only account for a small portion of the market, and almost all of those systems start out with at least a half-decent low power SSD. For devices with a bit of battery capacity to spare, there are cheap options that give better performance than the BG4.
However, within its niche, the BG4 is clearly superior to everything else we have tested. There's nothing on the retail market in any form factor that offers the power efficiency of the BG4, and for this reason it's not surprising that the BG4 is going to become an increasingly common feature of thin and light laptops, where vendors are always looking to save on space and power. The fact that the BG4 can't keep up with high-end M.2 2280 NVMe SSDs doesn't matter because it's plenty fast enough for a system where the CPU is also under severe power and thermal limits. The BG4 beats SATA performance and delivers a combination high density and low power that few vendors can compete with.
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eek2121 - Sunday, October 20, 2019 - link
There are a few 4 TB m.2 SSDs out there, they just sell out FAST so you typically won't even find them listed. You can still find plenty of 2 TB m.2 SSDs.mxnerd - Saturday, October 19, 2019 - link
Kioxia? Great product but what a bad brand name.s.yu - Sunday, October 20, 2019 - link
No surprise coming from Japanese manufacturers recently........s.yu - Sunday, October 20, 2019 - link
Looks like the takeaway from this is although Toshiba SSDs consistently fall behind Samsungs (the main reason they're regarded as the short straw in flash lottery), they may be more efficient, but hardly anybody tests for that.discostrings - Sunday, October 20, 2019 - link
The Toshiba BG4 is actually already available in the M.2 2242 format in retail channels as the Sabrent SB-1342-2TB, SB-1342-1TB, and SB-1342-512:https://www.sabrent.com/product/SB-1342-2TB
Yes, that's right: there's a 2TB 2242 variant! I was hesitant to believe it was actually available in that capacity, as I didn't see any sort of announcement, but I received one on Thursday and I can confirm it's quite real.
Unfortunately, these aren't useful for most current laptops with 2242 slots (that are primarily included for WWAN but which can also use NVMe drives like the RC100). As these SSDs use four PCIe lanes, they require the M key, while all laptops that I know of direct two (or less) PCIe lanes to the 2242 slot, and thus have a B key that prevents use of these drives.
So there probably won't be much of a market for these until there are laptops out with M-keyed M.2 2242 slots. It would be great to see a 2-lane variant with a B key in the short term for use in current laptops.
discostrings - Sunday, October 20, 2019 - link
I mixed terminology up a little bit in my prior post. The Sabrent drives use Toshiba BiCS4 NAND (which is also used by in the Toshiba BG4), but these are not rebranded variants of the same drive. Apologies for any confusion.peevee - Monday, October 21, 2019 - link
So they already have brands Toshiba, Lite-On and Plextor, all pretty valuable and respectable (esp Plextor I think), why do they feel like they need another one?Billy Tallis - Monday, October 21, 2019 - link
The decision to rebrand from Toshiba to Kioxia was made before the decision to buy Lite-On's SSD business. Continuing to use the Toshiba brand name long-term isn't an option since they aren't part of the Toshiba conglomerate anymore and need to IPO under a name they own. They don't get to use the Lite-On name either because they didn't buy the whole company, just the SSD portion. They might now own the Plextor brand.Targon - Monday, October 21, 2019 - link
If the laptop maker has a decent design, then it would make more sense to go with a small capacity SSD to keep the laptop price down and then put a better SSD in yourself. Get something with a normal 1TB hard drive but has the support for NVMe, and you then throw in a 1TB drive yourself. No need to feed the stupidity of people wanting a tiny machine that has a slow processor just to keep power demands low. Going with even a 35 or 45 watt CPU with a 15 inch display will give you a much more powerful laptop than these 15W CPU machines with a 11 inch screen designed for people who sit in meetings all day but have much lower performance.At least we are beyond the days of Intel Atom crap machines in that space.
MykeM - Thursday, October 31, 2019 - link
You can actually get a external USB-C SSD that uses this particular Toshiba BG4 SSD. It’s made by CalDigit know for its excellent Thunderbolt 3 docks. It’s called Tuff Nano and at the moment only comes in the ½ terabyte capacity. The read speed is just over 1GB/s (if the device USB-C supports USB3.x Gen2). And it’s tiny:l:https://www.caldigit.com/tuff-nano