morphine_

Windows' usage of TRIM has nothing to do with this. TRIM has been enabled by default since Windows 8 (7?). The MP510 could have a firmware bug and not perform TRIM when asked, though, which would go some ways to explain this situation. Also, the cache is for cache, just that; it doesn't count into the main storage area. Data flows from the PC to the cache, and is then written first-in-first-out (FIFO) to the main area. In case you're referring to the cache filling up, that only happens when you do a large operation (like copying a 10GB file). The cache fills up before enough data is written to the main area, and the drive slows down until it's done. That's normal expected behavior, and not the scenario here. If you're referring to the overprovisioning section, modern drives are overprovisioned from the factory. That's another reason why this behavior should not be happening, given that the overprovisioning is meant to provide extra cells precisely for when the drive starts filling up, and/or cells start dying, which isn't going to happen with a new drive. Remember the speed comes back up after a zero-fill. The statement about two or three slots to ease the load doesn't make sense, really. It's not a RAID setup.

If anyone from the SSD team wants to reach out, I also encountered this problem, but my MP510 960GB is currently sitting unused and I can run whichever diagnostics you want on it. I only got the write speeds back after a zero-fill, fwiw. Let me know if I can help diagnose this.

If anyone from the SSD team wants to reach out, I also encountered this problem, but my MP510 960GB is currently sitting unused and I can run whichever diagnostics you want on it. I only got the write speeds back after a zero-fill, fwiw. Let me know if I can help diagnose this.