The Crucial X6 4TB Portable SSD was actually a fairly complicated review for us to complete. What at first seemed like a simple capacity increase for an existing product series quickly snowballed into something much more complicated. For starters the Crucial X6 4TB Portable SSD was often uncapable of running at full speed on our motherboards 10Gbps USB Type-C port. We connected and ejected the drive 10 times and found that 6 out of 10 times it would only connect as a SuperSpeed device instead of SuperSpeedPlus. This meant that we were getting 420 MB/s sequential read speeds instead of 820 MB/s on CrystalDiskMark.
This issue was duplicated by Phison and Crucial and is actively being investigated. We have been working with both companies on this issue for several weeks and are glad they were able to duplicate. It might be something isolated to a small number of platforms as this issue was not observed on all the systems that we tired the X6 4TB drive on. AMD has had a number of USB connectivity issues lately, so hopefully we didn’t just add another issue to their list.
Update April 6th, 2021: Micron and Phison have been able to duplicate this issue and the cause involves the Pericom PI3EQX1004 USB 3.1 Gen2 10Gbps ReDriver used on the TUF GAMING X570-PLUS (WI-FI) motherboard. It is sending out a TX signal that is out of compliance with USB-IF and that is why we are not always able to connect at the right speed. Now Diodes Incorporated and ASUS are involved and looking for a solution to the issue that can be issued with a motherboard firmware update.
We also found out that the PI3EQX1004 ReDriver is already End of Life (EOL) and was replaced by the PI3EQX1004B1. Hopefully a fix can be developed for the ASUS TUF GAMING X570-PLUS (WI-FI) motherboard, but that board came out in July 2019 and was ‘refreshed’ when the ASUS TUF GAMING X570-PRO (WI-FI) came out in September 2020. Guess what? That newer model uses the newer Pericom PI3EQX1004B1 USB 3.1 Gen2 10Gb/s ReDriver.
We also ran into an odd quirk where the FINAL FANTASY XIV: Shadowbringers official benchmark would not successfully run from the X6 4TB drive. It would hang and Windows 10 would ask to send a crash report to Microsoft. We tried it on AMD X570 and Intel Z490 platforms without success on both USB Type-C and Type-A ports. This issue has been brought up to Crucial and Phison and they plan on doing a full USB analyzer test on this corner case soon.
Hopefully a new firmware can be released that fixes both of these issues. Other than those two issues that we encountered the Crucial X6 4TB Portable SSD performed as expected. We were able to reach the drives rated sequential read speed of 800 MB/s on CrystalDiskMark and it performed better than SATA-based portable SSDs in the majority of our benchmarks.
When it comes to pricing the Crucial X6 4TB Portable SSD runs $489.95. That is a very impressive price point and much lower than competing products from rival companies. The only real competition for this portable drive would be Sabrent with the Rocket Pro 4TB USB External SSD priced at $699. Crucial is hundreds of dollars less and offers around the same level of performance as both at NVMe solutions!
The Crucial X6 4TB drive is exciting as it is one of the largest portable SSDs that money can buy and enters the market at an aggressive price point. This drive will be appealing to those that need to store and easily transport gobs of data!
We are going to hold off recommending this drive right now due to the issues we encountered, but Crucial and Phison are actively working on them. We waited weeks to post this review in the hopes it was a super quick fix, but they are unable to give us an ETA for something like that. Since this is a product that you can run out and buy today there needs to be at least one “Legit” review for the community to digest. If they are able to fix the issues we encountered we’ll be sure to circle back here and give you the latest information.
Legit Bottom Line: The Crucial X6 4TB is impressive for the price, but needs some stability and performance improvements before we suggest spending almost $500 for it.