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I need to acquire a CPU with the RDSEED instructions for testing. As I work through the datasheets for Intel CPU's, it appears that AVX is the latest instruction set called out. See for example, an i5 CPU and an i7 CPU datasheet.

However, I have a MacBook Pro with an i7 with the AVX instruction set, but lacks both RDRAND and RDSSED. So I feel like I'm missing an important detail somewhere.

What instruction set architecture (ISA) is RDRAND and RDSEED part of? Or, what part of the spec should I be looking at to determine if a CPU has RDRAND and RDSEED?

(I realize RDRAND and RDSSED were introduced at different times. I just don't know how to determine a CPU with the feature).

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  • You have to tell us what processor you have. You linked to products separated by 2 years and 2 different generations. This information might not seem important but it might help us answer the question.
    – Ramhound
    Nov 12, 2015 at 11:52
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    @Ramhound - I don't have the processor. I need to buy a machine with a CPU that has RDRAND and RDSEED, and I'm trying to determine the processor it needs to fulfill the requirements.
    – jww
    Nov 12, 2015 at 11:56
  • " I have a MacBook Pro with an i5 that lacks both RDRAND and RDSSED." - I was asking you provide specifics about this.
    – Ramhound
    Nov 12, 2015 at 12:00
  • RDRAND are exist on Ivybridge or later products. RDSEED are Broadwell or later products.. I should point out "Intel® AES New Instructions" is will cover RDSEED and RDRAND.
    – Ramhound
    Nov 12, 2015 at 12:01
  • @Ramhound - My bad... The MacBook Pro is an i7 (not i5). But I can't find the processor specs. Apple does not appear to provide them, even on their Tech Spec page (its loaded with the MBP serial number). About all I can tell you is its the upgraded processor (2.4 GHz). The kid at the Apple store also told me it did have AES-NI and RDRAND, but that was a lie; it only had AES-NI. Lessons learned (for me): don't trust Apple, and don't let them ship you a device. Buy at the store, make them open it and inspect it on-site.
    – jww
    Nov 12, 2015 at 12:36

1 Answer 1

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RDRAND and RDSEED are not a part of any specific ISA extension set. They are their own set and have their own specific bits allocated in the CPUID instruction.

They were developed under the "Bull Mountain" codename and are today marketed as Intel Secure Key.

Intel Secure Key was added in Broadwell, so you need that or any later generation. Broadwell generation means Intel Core i5 or i7 where the 4-digit number appended to it starts with a "5". Like an Core i7-5775C. Intel later released the Skylake generation, that also includes these instructions. Skylake has codes starting with a "6", like Core i7-6700.

AMD has added RDRAND and RDSEED in Carizzo.

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    You forgot to mention that RDRAND is supported by Ivybridge products.
    – Ramhound
    Nov 12, 2015 at 12:46
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    That's correct. RDRAND is in IvyBridge and Haswell in addition to Broadwell and Skylake. However IvyBridge and Haswell lack RDSEED.
    – Vojtech
    Nov 12, 2015 at 13:19
  • Thanks Vojtech. it took three tries, but I finally got my hands on a 6th Gen i7.
    – jww
    Nov 29, 2015 at 2:13

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