During my initial benchmarks of the HP EX950, I noticed that some real-life tests came back lower than expected. They were still "good" but not as high as what I would have expected given the drive's positioning on the market and the praise it got from other reviewers. After more testing it became evident that the issue is related to reading and writing large chunks of data in parallel, at low queue depth. Our sequential QD1 mixed test simulates the typical "read data, process, and write back" process that happens in a lot of programs. Surprisingly, that was the only test that showed less than stellar results—everything else, sequential and random IO, looked great and was suggestive of this being one of the fastest drives on the market. Most people shopping for SSDs look at sequential results only because it is here where they see the big multi-gigabyte numbers vendors are presenting in their marketing (and optimizing for).

Looking at our real-life performance numbers, things were different. While there weren't any huge slowdowns, the numbers clearly showed that the EX950 wasn't performing as well as other drives using similar components. For example, the ADATA SX8200 Pro was 4% faster on average, which is a fairly large difference. I reached out to HP and BIWIN with my data and provided a test case, too. They were quick to respond and promptly confirmed that they can indeed reproduce the problem I've been seeing on my drive, which came with the latest retail firmware. After a few days they offered me a firmware update, which fixed QD1 sequential mixed speeds. This update isn't available to the public yet. They are working on an easy-to-use 1-click updater that makes it straightforward for consumers to upgrade their drive.

After the firmware upgrade, the usual synthetic benchmarks, like random and sequential read/write, were unchanged—QD1 mixed sequential was the only test that increased substantially. All the data is included in this review. Now the EX950 performed like a completely different drive that kept smashing records. Many of our tests suddenly ran 10%+ quicker—pretty impressive.

Overall, when averaged over all our real-life tests, the HP EX950 with the firmware update is the fastest SSD we ever tested, 5% faster than the drive before the upgrade. It beats the ADATA SX8200 Pro by 1% and is even faster than the much more expensive MLC-based Samsung 970 Pro. One test I would like to highlight is "Steam Unpacking". If you've ever waited impatiently for a Steam game release and were sad because the preload had to be decrypted and unpacked after launch, which takes forever, the EX950 is the best choice. It is a good deal faster than anything else, letting you play earlier than your friends.

Our testing shows that the SLC cache is quite big, sized at 300 GB (or 15% of the total capacity). This will suffice for all but the largest workloads, such as restoring a full-drive backup from a sufficiently fast source (such as another NVMe SSD, however unlikely). What's also worth mentioning is that even when the SLC cache is exhausted, write speeds remain very high—1.3 GB/s until 1.2 TB have been written. This is better than nearly all other TLC SSDs we've reviewed so far. Of course, once write activity stops briefly and the SLC cache has time to flush to TLC in the background, write speeds are quickly restored to the full 2.7 GB/s.

Probably the weakest test result was our thermal testing. Since the EX950 lacks a heatsink, it will heat up quickly when heavily loaded. Just one minute into our stress test, temperatures reached 90°C, and the drive started thermally throttling. The throttling behavior is well-mannered, though. Write rates don't fall off a cliff immediately. Instead, the drive will continue writing at 1.2 GB/s, which is still plenty fast. Having a proper heatsink would definitely be a nice touch, especially for enthusiasts. Maybe the heatsink could be bundled separately to retain compatibility with notebooks and some motherboards while giving desktop users the option to install it if they feel their thermals are too high.

Currently, the HP EX950 2 TB SSD is listed for $273 online, which is more than reasonable. At that price point there is very little competition. I found only two alternatives. The first is the Sabrent Rocket Q 2 TB at $240. While that drive is much more affordable, it is much slower than the EX950 because it is based on QLC flash. The second is the ADATA SX8200 Pro for $260, which performs similarly. I also have to praise HP for releasing a 2 TB version—many vendors don't do that. For example, the Samsung 970 Pro isn't available in that capacity, and neither is the Crucial P1. If you're looking for a large high-performance SSD, then the HP EX950 should definitely be on your list—once the firmware update is made publicly available.