Ultimate X5 SLOWER than X2

[gomactrading]

Just compared speed of avi to dvd conversion on same machine, same file, same settings. X5 took about 45 minutes (all hardware accelerations enabled on i7 NVIDIA CUDA) and about 30 minutes with X2. Same with acceleration disabled. On X5 KMP_DUPLICATE_LIB_OK=TRUE had to be enabled as environment variable as otherwise X5 would not start. Does anyone know why such a dramatic decrease in speed is possible and is there a solution to the problem?