HighPoint's Rocket 1608A achieves impressive storage performance and is the fastest solution of its kind in the market. Later this year, Sabrent Apex will come out with a similar design, probably at higher pricing. Besides that, I'm not aware of any competitors. The HighPoint Rocket 1608A brings with it eight M.2 NVMe slots that have full PCIe Gen 5 x4 support, which means any Gen 5 drive will be able to deliver its maximum performance. The connection to the host CPU uses a PCIe 5.0 x16 link—all this is powered by a Broadcom PEX89048 PCI-Express switch, which juggles data between the drives and the CPU. Just to clarify, unlike other storage expansion cards, the R1608A does not need PCIe Bifurcation support from the motherboard, which internally splits a x16 connection into four independent x4 links. Booting from the R1608A is possible, the BIOS sees all the installed NVMe drives as additional SSDs, just like they would appear in native M.2 slots on the motherboard. This includes the ability to Secure Erase them from the ASUS BIOS, for example.

While the Rocket 1608A does not have any native RAID capability, this is not such a big deal in my opinion, at least for most scenarios. Windows comes with good support for creating software-based RAID-0, RAID-1, Striped and Storage Spaces disk drives. I actually prefer the Windows solution, because it means you can take the drives to any other machine, import them and they will run fine. Proprietary RAID stacks often require specific hardware combinations to work at all, which also complicates data recovery. The only exception is that due to a Windows limitation, booting from RAID-0 is not possible (RAID-1 boot works fine). HighPoint will release the R7608A add-in card soon, which has native RAID support.

While "Gen 5" is certainly the highlight, the R1608A can run in a second, very interesting configuration, too. If you fill it up with high-end PCIe Gen 4 drives, you will be able to reach 56 GB/s, too, at a much lower overall cost. HighPoint demonstrated this with eight Samsung 990 Pro SSDs, and they reached 56.6 GB/s reads. This is possible because each drive can reach 7 GB/s on its own, so times-eight that reaches the desired 57 GB/s almost exactly. Not matter if Gen 4 or Gen 5 SSDs are used, running at such transfer rates is possible only in very limited use-cases though. CrystalDiskMark is well-known for maximizing the capability of storage, but even that required some benchmark setting changes to unleash the full potential of the adapter card. While we can confirm the "57 GB/s" performance claims of HighPoint, our standard synthetic tests do show much smaller performance gains. Even with eight drives in RAID-0 the highly important 4K Random Queue Depth 1 results didn't move at all and sequential transfers cap out at a bit over 10 GB/s, too.

While usually Intel systems are the gold standard and everything is optimized for them, things didn't work out so well for the Rocket 1608A in our Intel-based SSD Test System. No matter what I tried, the card was unable to run at x16 5.0 on the ASUS Z790 Dark Hero. HighPoint confirmed that there is a problem with link speeds on this specific board, but they couldn't offer any workaround or explanation why this is happening. I tested four different Intel Z790 chipset motherboards with the card and not a single one was able to reach the promised speed. This basically means that the R1608A cannot be recommended for use in an Intel system. On AMD everything worked fine, plop in the card, it runs happily at x16 5.0. This is good news for users of Threadripper and EPYC systems—I wouldn't expect any compatibility issues here either.

Our real-life testing is a bit more limited for this review, because some of our benchmark require the tested drive to be the boot drive. We couldn't run game load time tests either, because the x16 card occupies the GPU slot, which is an important tradeoff, especially for gamers. Averaged over our tests we saw a 3% performance improvement over the native x4 Gen 5 CPU-connected slot, no matter the RAID configuration. This is interesting, but can be explained by the different workloads working best in specific storage scenarios. For example, finding a certain text in thousands of files ran best with just a single drive, and each increase in RAIDed drives lowered performance by around 2%. On the other hand, compiling a library of over thousand MP3s definitely completed faster, the more drives you link together, by 3% for each increase in RAID members. Even a mostly sequential scenario, like reading 75 GB of game files does favor a 2-drive setup. This is really more evidence that the workload is what matters most for these RAID configurations.

A truly impressive result is how well a RAID configuration of eight Gen 5 SSDs can soak up incoming data. In our Sustained Write Performance test we saw a new record. Even with a queue depth of 1 we were able to write over 11 TB of data before there was any meaningful drop in performance due to the SLC caches of the drives completely filling. With a single Gen 5 SSD, this happens after only 200 GB written. This unexpected +5500% improvement is due to the fact that each single drive is working much less hard than in the single drive test, because the writes are split over eight drives, giving each of them additional time to flush the SLC cache to TLC in the background. If you need to write a ton of data in as short a time as possible, then the HighPoint Rocket 1608A is the perfect choice for you.

The biggest drawback of the R1608A for a non-server usage scenario is the high fan noise. While there is some level of temperature control, the fan really runs too fast pretty much all the time. Even when the drives and the PCIe bridge are idle, we measured the fan to run louder than most modern graphics cards (at full load). Considering an idle temperature of sub-40°C, there is no reason why the fan can't run slower and allow slightly higher temps. For testing we ran just the bare card without any drives installed, and the fan was still loud, which suggests that the fan control algorithm is not optimized well at all. At full load, the total power consumption of the card with eight drives is over 150 W, which needs to be dissipated. Allowing higher fan speeds in this specific load scenario is fine of course.

Priced at $1500, the HighPoint Rocket 1608A is definitely not cheap. This pricing pretty much puts it out of reach for most non-commercial users. I suspect that the high price is mostly due to the Broadcom controller, which probably costs a thousand bucks alone. They are pretty much enjoying a monopoly, so they can charge whatever they want for these chipsets that usually go in expensive enterprise solutions. To put things into comparison, just the IO die of the cheapest $200 Ryzen AM5 processor has 24 PCIe Gen 5 lanes and could handle these tasks, so it would just take two IO dies from AMD linked together on a PCB with custom firmware, and you'd be good to go for a fraction of the cost. But of course AMD wants to sell full CPUs, so this isn't going to happen any time soon. Eight 2 TB Gen 5 SSDs will set you back around $2000, so adding another $1500 on top of that isn't a monumental difference, but is still significant. On the other hand, if you need this kind of storage performance, you're probably making money with it and should be able to recoup your investment. I touched on this briefly before, another approach is to use cheaper Gen 4 SSDs instead. Now the drives will cost $1200, add $1500 for the controller card, and you can save $1000 over the Gen 5 config, with similar performance. A big problem that still remains is the fan noise—I can't imagine many people who would be willing to work at such a noisy workstation.