Bitlocker Performance Impact on SSD

You should have a negligible performance impact with most SSDs. Especially with the latest Intel CPUs that can do hardware AES way faster than a drive (any drive) can read or write. My MacBook Pro pushes over 900 megabytes per second with AES according to the TrueCrypt benchmark, and that's a laptop.

On my desktop I use 4 Samsung SSDs in RAID0 and I have BitLocker turned on. TrueCrypt on this same machine reports over 5GB/sec for AES. (Two 6-core Xeons...)

That said, the SandForce SSD controller is said to do some internal compression/dedupe (which was proven via benchmarks that used large compressed files that it could not "optimize"). Obviously this is not going to work at all with BitLocker where every encrypted sector will be completely unique and uncompressible. So if you're planning on using an SSD, don't get a SandForce one - or if you do, make sure you can return it if you find that performance really degrades after you turn BitLocker on.

Because BitLocker does not really change the usage characteristics of the drive other than changing the data itself (e.g. it does not cause the OS to write randomly instead of linearly), it should have the same impact on an SSD that it would have on platters. That is, I would still expect the 20%-10% decrease in performance that MaximumPC found, as mentioned in the thread you link to. Note that the speed of BitLocker may be bottlenecked by either the processor or the drive. That is, if the processor can encrypt/decrypt faster than the drive can read/write data, then file I/O will occur at near the speed of the drive. If your processor is overtaxed, the processor may limit file I/O speed (although I believe hardware-accelerated cryptography should minimize the likelyhood of this happening).

On Dell Inspiron 15 7577 Intel i7-7700HQ Samsung 950 PRO 256GB NVMe Windows 10 64 bit NTFS I see indication of performance penalty by Bitlocker on small random files(e.g. compilation process), VeraCrypt is bad, transient(no need to encrypt) in memory is fast (e.g. get more memory, script mount of in memory disk and copy of files for compilation).

Not encrypted:

Not encrypted