The Intel TRNG design used for RdRand in Ivy Bridge has an impressively low transistor count so I don't think die-cost alone is the issue. http://spectrum.ieee

The Intel TRNG design used for RdRand in Ivy Bridge has an impressively low transistor count so I don't think die-cost alone is the issue. http://spectrum.ieee.org/semiconductors/processors/behind-intels-new-randomnumber-generator/0 http://spectrum.ieee.org/semiconductors/processors/behind-in... http://en.wikipedia.orghwiki/RdRand http://en.wikipedia.orghwiki/RdRand I suspect they just didn't consider RNG quality as a big factor in the usefulness of the design. TPM pre-dates the recent advances in on-die TRNG design. Plus the chip tends to live on a low-speed bus on the system which makes it inherently a bit crappy as a place to keep a high-bandwidth application like an RNG.