I noticed something else related to the vector processing. I was playing around with this code this evening, trying a few things, and I noticed that when I used the code posted in this thread with a vector size of 4, and enabled SSE and vector processing with FPC 3.0, I got the same internal error as the poster got when using AVX with a size of 8, if I did an "a xor b" operation instead of an "a + b" operation. If I did the "a + b" operation as shown in this thread, it works with SSE, but an xor operation will trigger the internal error. I suspect this isn't correct, because it seems like an xor operation should be possible, and in any event the internal error seems like it's not the correct response. Anyhow, I thought I should mention it because it looks like there might be some issues with the SSE vector processing as well.