The Kingston KC2500 is more of an evolutionary upgrade over the KC2000 instead of a big revolution, Kingston is quite clear about that. Under the hood, both drives are based on exactly the same design, a Silicon Motion SM2262ENG controller is paired with Toshiba 96-layer TLC flash and 1 GB DRAM cache. Both drives connect to the host interface over a PCIe x4 Gen 3 link. The secret sauce for the KC2500 is in the SSD firmware. It seems Kingston has found a way to eke more performance out of the existing design.

Our synthetic testing confirms that random IO runs nearly identical on the KC2500, only sequential transfers are improved. The KC2000 achieved 2.7 GB/s read and 2.2 GB/s write in our mix of low-threaded queue depths, and the KC2500 does run at 2.9 GB/s and 2.7 GB/s, 20% faster for writes, 8% faster for reads. Pretty impressive for just a firmware update. When you compare the packaging of both drives, the KC2500 packaging reads "45x faster than a HDD," while the KC2000 claims "35x"—I'd say that's a little bit of a stretch, especially once you look at actual real-life performance.

Our mix of 20 real-life tests, tested at 80% filled storage capacity, shows an average performance gain of 1% over the KC2000, which makes the KC2500 the third-fastest SSD we ever tested; 1% ahead of the Gigabyte PCIe Gen 4 SSD and 1% faster than the HP EX950. Other high-performance M.2 NVMe SSDs like the Kingston A2000, Samsung 970 EVO, Crucial P5, and WD Black are 5% slower, which is not a lot but still significant. Typical SATA SSDs are almost 30% slower. Only the ADATA SX8200 Pro and much more expensive Samsung 970 Pro are 1–2 % faster.

1% gain over the KC2000 doesn't sound like much, but you have to consider that it's much harder to gain 1% at the top performance end of our test group than at the bottom. On the other hand, one has to wonder why Kingston didn't simply release a firmware update for their existing customers; I think such an action would go a long ways for customer loyalty. Flashing firmware isn't trivial, though, and I can imagine support calls of "oh I didn't know it would delete all my data" (no matter how often the updater warns that the drive gets cleared), or "my kid pressed the power button during the firmware update, please help".

Sequential write performance of the KC2500 is very good. On average, the drive will sustain 1.1 GB/s when you fill up the whole 1 TB capacity in one session. This is a very good result, better than every other TLC-based SSD we've tested except for the HP EX950. Of course, when you momentarily stop the write activity, the SLC cache will free up capacity immediately, so full write rates are available as soon as you give the drive a moment of time to settle down. Not much to report on thermals other than the fact that the sensor reports back temperatures which are around 20 °C lower than is actually the case, not a big deal.

Kingston is pricing the KC2500 at $185 for the tested 1 TB version, which is simply too much for the current market. Yes, you get a five-year warranty with this drive, which is one of the fastest we have ever tested, but the competition is strong. Noteworthy alternatives are the HP EX950 ($130) and ADATA SX8200 Pro ($120), and Kingston's own KC2000 ($150). If you can live with slightly slower performance, you can save big; the Crucial P1 is $100, and the ADATA Swordfish is even $95. A price increase of $35 over the KC2000 is too high in my opinion. Personally, I would be willing to pay $10 extra maybe, but not more. At $185, the KC2500 is also not that far off from the $230 Samsung 980 Pro.