Intel Corp (INTC)

[wbmw]

"SDP" is just TDP when running tablet workloads.

Wrong. SDP is a choice given to the OEM to redefine the steady-state power cap of the processor.

At TDP, all frequencies are "guaranteed", meaning even the worst-case workload will still clock at the frequencies stated for the processor.

However, the OEM has the choice to load a value in a register that sets the power cap of the processor at TDP, or at any point lower than this, up to and including the SDP, which is like a "floor" of dissipation of the processor.

This is convenient for the OEM, because their design may be able to accommodate 5W of cooling, or 7.5W of cooling, or 10W of cooling - but all of these can be loaded into the processor, and the CPU will ensure that under steady-state conditions (defined as 1-30 seconds worth of turbo), then it will throttle frequencies until the cap is reached.

If set to TDP, then there is essentially no throttling, and you are operating at the quoted frequencies. At decreasing values of the power cap, more throttling is required, up to and including the LFM frequency.