Finally! Our first PCIe 5.0 SSD review is live, covering the Corsair MP700 SSD that just got announced today. In the months leading up to this launch we've been hearing a lot about the new Gen 5 solid-state-drives, which can reach twice the throughput of Gen 4 SSDs, thanks to a doubling of the interface transfer rate. In theory PCIe 5.0 x4 allows 16 GB/s—Corsair advertises "up to 10 GB/s" in their marketing materials. The underlying reason is that the Phison E26 controller currently tops out at 10 GB/s, a new revision allows up to 12 GB/s. Besides the new controller, Corsair is also using the newest flash from Micron, their 232-layer 3D TLC NAND. As expected, a DRAM cache chip is included, too. 4 GB DRAM on a 2 TB-class drive is surprising, usually, especially on Phison, we're seeing 1 TB NAND = 1 GB DRAM. More is better of course, so no complaints here.

Synthetic performance results of the Corsair MP700 are very impressive, especially when it comes to sequential transfers. We can confirm that Corsair's "up to 10 GB/s" claim is accurate, we actually peaked at slightly above that. However, that's at higher queue depth. Typical consumer workloads are at low depths, here we got 6.5 GB/s read and 8.5 GB/s write, which is still mighty impressive. Random IO on the other hand is virtually identical to the results of PCIe Gen 4 drives, like the Phison E18-based Kingston KC3000.

Phison has a long history of optimizing their controllers for typical synthetic reviewer workloads on an empty drive. That's why it's important to also include real-life testing. We're even running those tests with the drives filled to 80% capacity, not empty. This approach puts additional pressure on the various algorithms and the SLC cache, just like in real-life. Here the MP700 does very well, too, and comes out as the fastest SSD we've ever tested, but by a relatively small margin of 2% on average. Our mix of workloads consists of many real-life scenarios, the biggest wins can be seen in situations where sequential transfers matter, like during file copy. Random IO workloads like applications are basically tied with Gen 4 drives, just like game load times. That's not to say that the MP700 is slow, but it seems we're experiencing a repeat of what happened when we saw the first Gen 4 SSDs, which achieved only small real-life improvements over the most mature Gen 3 drives at the time.

We've been hearing about how awesome DirectStorage is for game load times and in-game texture streaming, especially with Gen 5 SSDs. The only title with support for DirectStorage so far is Forspoken which has been tested to show no meaningful difference between DirectStorage on or off. Also it's a very mediocre game, so we're really missing data for this use case, but I seriously doubt that game studios will release games that only run optimal on a tiny subset of their customer base. We'll know more in the coming months, but for now DirectStorage is a complete non-issue for your SSD purchase.

Thanks to plenty of SLC cache, the MP700 can easily absorb large incoming write bursts. With 660 GB, the SLC cache is at the maximum size feasible for a 2 TB TLC drive. Filling 660 GB in SLC mode consumes 1980 GB of TLC capacity. This leads to the tradeoff that once the SLC cache is full, the drive has to work extra hard to make space for incoming data, by moving other data from SLC into TLC. Writing into pSLC is very fast at 8 GB/s, but once exhausted, transfer rates drop to 1 GB/s, which is slower than some PCIe Gen 4 SSDs that we've tested. Filling the whole capacity completed at 1.5 GB/s, a good result, but it's not considerably better than the leading Gen 4 drives in our test group.

Our new power consumption tests show that the MP700 really uses a lot of power. We've measured up to 10 W, which is basically 50% more than what we've seen on Phison's E18 Gen 4 controller. Hitting 10 W is quite rare though, you should rather plan with 5-6 W during typical loads, which is still a lot. Of course you're getting higher performance at the same time, but our numbers show that even when running at only 1 or 2 GB/s, the power consumption is still high. It seems that once the controller goes out of idle, it will always use 4 W at least, no matter how little actual work it does. This suggests that there's still lots of untapped potential in its power optimization. Overall energy efficiency is lower than most Gen 4 drives on the market—definitely something that Phison has to work on.

On an SSD, all power is converted into heat—which means that the Corsair MP700 needs serious cooling when you make it work hard. Corsair ships the drive without a heatsink, it's your own responsibility to use your motherboard's M.2 cooler or buy an aftermarket thermal solution. I'm not convinced that this is the best solution, especially when other Gen 5 previews have shown heatsinks of various sizes on competing M.2 Gen 5 drives. In our thermal testing of the bare drive, without any airflow in the case, which is a worst-case, we saw thermal throttling during reads after 90 seconds at full speed (or ~500 GB total transferred) and after 55 seconds of writes (~240 GB total transfer). While these durations seem short, you have to consider the immense amount of data transferred in such a short duration. For the vast majority of users I'd even say that there's no need to go crazy with cooling, 99.99% of the time you will not move enough data to make the drive throttle; and you also need a data source or target that can match the speeds of the MP700. What makes things problematic though is that once thermal throttle is reached, the drive will stop working until a power cycle. No, it will not slow down until it cools off, it will simply disappear to the rest of the system and never come back, even when cooled down. This looks like a firmware issue to me that should be fixable. Alternatively, it may be linked to the 4 W heat generated even under light loads, indicating that any amount of throttling may not be able to sufficiently decrease the heat output and allow the drive to cool down on its own. More testing and research is needed here.

According to Corsair, the MP700 2 TB will sell for $290, which is not exactly cheap, considering how much SSD prices have come down in recent months. For example you can get WD's SN850X 2 TB for $160, the Samsung 980 Pro is even only $130. While the Samsung 990 Pro is barely faster than the 980 Pro (it's still Gen 4), even that is just $190, so still $100 less. Kingston's KC3000 is currently $145, similar Phison E18-based drives can be found even cheaper. This huge gap in price/performance makes it difficult to recommend the MP700. If you absolutely must have the fastest SSD, then the MP700 can be a good choice, but make sure you put some cooling on it.