Join the Discussion - To hell with nVidia's definition of SFF ready. What should be the actual SFF standard?

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As with all generations of PCIe, 4.0 is entirely (pysically and electrically) backwards-compatible with 3.0, 2.0 and 1.0. A PCIe 4.0-based GPU such as the Radeon VII or upcoming RX 5700 series will plug into any old PCIe board and work just fine (barring other incompatibilities such as UEFI issues). The controllers just step down to a compatibility mode. If compatibility only went one way, that would mean that GPUs, for example, wouldn't adopt the new tech until the vast majority of the potential buyers had PCIe 4.0, which likely won't be the case for another 5 years. In other words, limiting backwards compatibility would kill the standard before it even launched. Even the newly presented proposal for PCIe 6.0 maintains full backwards compatibility to 1.0.

[QUOTE="Valantar, post: 152113, member: 5738"] As with all generations of PCIe, 4.0 is entirely (pysically and electrically) backwards-compatible with 3.0, 2.0 and 1.0. A PCIe 4.0-based GPU such as the Radeon VII or upcoming RX 5700 series will plug into any old PCIe board and work just fine (barring other incompatibilities such as UEFI issues). The controllers just step down to a compatibility mode. If compatibility only went one way, that would mean that GPUs, for example, wouldn't adopt the new tech until the vast majority of the potential buyers had PCIe 4.0, which likely won't be the case for another 5 years. In other words, limiting backwards compatibility would kill the standard before it even launched. Even the newly presented proposal for PCIe 6.0 maintains full backwards compatibility to 1.0. [/QUOTE]

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