I boot externally via USB 3 using a Samsung Pro. Write speeds were great for a while (~420MB/Sec), but now benchmarking puts me at around 170MB/Sec, sometimes as low as 90MB/Sec. Sometimes as high as ~212MB/Sec, but never has high as it should be. Read speeds are a consistent ~430MB/Sec, so I know USAP is functioning and the speed is available on the bus. It seems like an issue with the drive. My research shows Samsung being called out and that this is a known issue. Customer Service claims the drive is designed to be used with TRIM and that I can send to drive in for inspection under warranty. Not having another SSD in the house means that my machine is put out of commission for awhile. I am debating the merits of sending the drive in, as it still operates very snappily despite this very low benchmarking. Maybe the low write speeds don't matter for my uses? I don't know. Have others used SSDs for six months or more through USB 3 and not found this degradation? I am wondering if I should have gone with the inexpensive Transcend StoreJet Thunderbolt drive just for the TRIM function. I was under the impression TRIM was not really necessary, but maybe it is? Maybe with only some manufactured drives and not others?