This PCIe 4.0 add-in card can support up to 21 M.2 SSDs

Shawn Knight

Posts: 14,813   +181
Staff member
In brief: I've always had a knack for excessively fast storage systems, and Apex Storage's new X21 has certainly caught my attention. The Apex Storage X21 is a dual-board add-in card that can accommodate a whopping 21 PCIe 4.0 M.2 SSDs. And no, that wasn't a typo.

According to Apex's website, all major brands of M.2 NMVe SSDs are supported including QLC, TLC, MLC and Intel Optane drives. RAID deployments in Windows and Linux are also supported, the company notes.

What sort of options are you looking at when it comes to configuration? I suppose that depends on what you are aiming to accomplish with your build.

According to Apex's website, you would be looking at 168TB of storage when populating each slot with an 8TB SSD. Future 16TB drives could push capacity up to 336TB. Optionally, you could load it up with lower-capacity cards with a focus on speed.

Apex says that with a single card, you can expect sequential read speeds of up to 30.5GB/s and sequential writes of 26.5GB/s. Add in the second card and max speeds jump to 107GB/s on the sequential read side and 70GB/s for sequential writes.

Do you need this? Almost certainly not. Plus, it would cost a small fortune to fully configure it. Even with the low cost of flash memory today, it would still cost over $5,000 to fill it with Samsung 990 Pro 2TB drives – and that does not even include the cost of the add-in card itself. Trade out the Samsung 990 Pros for Sabrent's 8TB Rocket 4 Plus NVMe SSDs, currently going for $1,099.99 each on Amazon, and your SSD bill skyrockets to over $23,000.

The card does come backed by a lifetime warranty. Unfortunately, Apex has not said when the X21 will launch or how much it will sell for. It is also a bummer that it does not support PCIe 5.0 drives but then again, trying to keep 21 of those cool would be a serious challenge.

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Posts: 613   +1,110
Hmm. Something like this with like 4 slots would do nicely. Motherboards don’t like more than 2 M slots most of the time.


Posts: 1,271   +1,842
Having this connect to the mobo on PCI-E 4 makes absolutely no sense. Yes, the SSDs are fine on v4, but having just 4 of those x4 SSDs already fully saturate the x16 AIC's full bandwidth. So even on v5 with twice the bandwidth, the bus would be a limiting factor with more than 8 SSDs. This AIC can have 21.

And the "second card" doesn't have its own insert, it just installs on top of the first card with a riser. So they share the same (very limited) bandwidth to the mobo.

"Add in the second card and max speeds jump to 107GB/s on the sequential read side and 70GB/s for sequential writes."

I'm really curious how they plan to achieve that, given the fact that the maximum *theoretical* throughput of PCI-E v4 x16, that this AIC has, is 31.5 GB/s. Which is exactly my point. They'd need PCI-E 6 to saturate this many SSDs and actually deliver those numbers. Or go dual slot *and* PCI-E 5.
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Posts: 1,271   +1,842
Hmm. Something like this with like 4 slots would do nicely. Motherboards don’t like more than 2 M slots most of the time.
You can already have that for like $80.

Or the gazillion even cheaper knockoffs on Ali, but of course who knows if they work at all or not...

Aus spot

Posts: 170   +168
More than double your speed by having two. How does that work?

Where is the active cooling for all those ssds?


Posts: 2,752   +3,335
Staff member
Looking at the screenshots, I only see 11
It's a dual-board card -- one PCB has 11 M.2 sockets, while the other has 10.



Posts: 12   +8
ONG bro, I NEED to download all of the games I own from every single launcher so I dont have to download them again because my internet is terrible

Lol ikr?

I've already got a Sabrent NVMe M.2 SSD to PCIe X16/X8/X4 Card in the case rn. Basically I built with 500Gb 980 Pro for the OS/apps and 1Tb of the same for the AAA games (absolutely worth it with increasingly large file sizes and long loads) I soon realised that 1Tb wouldn't be enough. My internet speed is good enough but what with illness and occasional game burnout, I needed a good selection installed to appease without downloading on and off as mood suited. So I got that card, put the 1Tb on it in the third PCIe x16 slot (slightly slower but not by much) and got a 2Tb 980 pro for the original slot used. Could've got a 4Tb drive but that was a bit too much at the time... though probably not so much now lol. 36 games of varying genre and size installed and maybe 1Tb left rn which tbh I could easily fill from my 'to be played eventually' library list. I only have much of the 1Tb open rn from uninstalling a few outliers to be ready for upcoming releases and a sale.

One of these add-ins, even with only 4-6 slots would be both a dream come true and a nightmare for me. I happen to have a couple of spare PCIe 3.0 NVME's right here looking to be used for my second tier games... but honestly, while I'm happy with the rest of my specs I've not needed excuses to buy more NVME's of late.