DUAL_EC_DRBG would have been the dumbest possible way to backdoor RDRAND. It would also imply that Intel is somehow able to slip in circuitry able to do two 256

DUAL_EC_DRBG would have been the dumbest possible way to backdoor RDRAND. It would also imply that Intel is somehow able to slip in circuitry able to do two 256-bit elliptic curve scalar multiplications in under 300 cycles, and pretend it is AES circuitry which would normally be orders of magnitude smaller and faster.