Silicon Power 4TB UD90 NVMe 4.0 Gen4 PCIe M.2 SSD R/W up to 5,000/4,500 MB/s (SP04KGBP44UD9005)

I am a huge fan of SP memory and memory products. I have been buying a lot from them recently. I got this because I wanted a decently large primary storage drive for my new main pc. This drive is nice and fast, OS boots in seconds, I haven't had any problems with any of my systems recognizing SP drives or memory. Installation was a snap, and performance was as advertised. I've built a handful of systems both AMD and Intel based and the Silicon Power nvme drives I've been using just work. They don't have to be the very fastest drives out there, but the Gen3 are plenty fast for my needs, even gaming. These are fantastic options that don't cost a ton.

Needed more space in my computer, this nvme SSD works great and had fast loading files abd booting the laptop.

The 1TB Silicon Power UD90 surprised me with its speed and stability. Read and write speeds are excellent, and you'll notice the difference immediately when booting up your system or transferring large files. Installation was easy thanks to the M.2 form factor, and the compact design fits perfectly in my PC. Furthermore, it offers a great balance between performance and price, making it an ideal upgrade for improving both everyday use and gaming.

Great quality at a good price(pre 2025 AI inflation).

EDIT: It was a bad M.2 slot. Drive was fine. My bad. Installed Windows to it and the drive partition table corrupted after a few days. No huge data loss or anything, but still inconvenient. There are no means to update the firmware provided by Silicone Power. Frequent 2101 detection errors. Very likely to be returning this.

Absolutely, here’s the review rewritten from your perspective, making it clear that you also experienced the slow speeds and recommend staying away from this drive: --- **Avoid This Drive – Slow and Disappointing!** I didn’t personally buy multiple Silicon Power drives in the past, but after seeing detailed reviews and specs, I expected the UD90 to be a decent budget SSD. It’s advertised with a Phison E21T controller and TLC NAND, boasting speeds of 5000MB/s read and 4500MB/s write in SLC mode. On paper, it looked like a solid choice with a 3000TBW rating. However, after putting it to use, I immediately ran into severe slowdowns. Copying large files (about 1TB) exposed just how bad the performance is—sustained writes quickly dropped to an abysmal 150MB/s–250MB/s. Further testing confirmed that the SLC cache is incredibly small (only 15GB–65GB), and once it runs out, the drive slows to a crawl. The controller struggles to flush the cache efficiently, making recovery painfully slow. Benchmarks show that outside of the SLC cache, speeds tank to around 250MB/s for reads and 150MB/s–250MB/s for writes. This strongly suggests the drive is using QLC NAND instead of TLC, which explains the poor sustained performance. QLC not only has lower endurance but also significantly throttles after the cache fills up—impacting both write and read speeds. And for what? To save $10–$20 over a proper TLC drive? Absolutely not worth it. Temperature-wise, it stays reasonable at around 49°C with a heatsink, but that doesn’t make up for the glaring performance issues. If this drive actually used TLC with a proper cache, it could have been a great value option. Instead, it’s a classic case of cutting corners at the cost of real-world usability. I also reached out to Silicon Power’s support to confirm the NAND type and explain the performance problems, but after three days with no response, I decided to dig into the issue myself. In the end, I avoided further frustration and went with a slightly slower but *far* more reliable TLC + DRAM drive (TeamGroup MP34) for just $20 more. If you’re considering this drive—don’t. The performance limitations make it a terrible value, and there are far better options out there.

I purchase this 4TB SP UD90 back in '23. I found the speed adequate for my needs. Worked like a champ until one day it did not. I was using it as a secondary drive for my steam games. Disappeared from BIOS, nothing in disk manager. Well I figure I'd see if SP would honor their warranty and they absolutely did. Went through the RMA process and two weeks later I have a replacement UD90. I purchased another 4TB UD90 and a 2TB 2230 UD90 (For my steam deck.). I'm very please with this company and back it up with my wallet.

Works for me. Read and write speeds are typical. I use this with an enclosure for media storage and it works well. The heatsink can be problematic for some enclosures if there is tight clearances, but for me I just removed the thermal pads from the enclosure and it fit just fine.