By not doing much realtime garbage collection the random write speed can drop significantly over time, but at a lower write speed the 830 isn't penalized as much as other drives. After 20 minutes of 4KB random writes the SSD 830 will only write at a rate of around 20MB/s. There's a significant drop in performance but the drive is still able to deliver ~100MB/s speeds. Here's what the drive looks like after our torture test:
Sequential read/write performance should be around 400/330 according to Iometer. After 20 minutes of torture I ran a single sequential read/write pass to measure how much of a hit the drive took. To quantify the behavior I filled all user addressible LBAs on the SSD 830, then proceeded to run our random write torture test on the now-dirty drive. These days things are a lot better but it's still a concern. In the old days the Samsung controllers would hit single digit write speeds, often slowing down to sub-HDD speeds. Unfortunately this approach can result in pretty poor performance over time.
Samsung doesn't do a lot of active garbage collection while writing in order to maintain ultra high write speeds, instead it prefers to clean up the drive during periods of little to no IO activity. My biggest issue with Samsung SSDs in the past has been their extremely poor performance over time.
