Replies to post #121528 on Intel Corp (INTC)

[wbmw]

For example Intel specified the N2805 with 4.3W TDP and 2.5W SDP and for Haswell-Y the datasheet says 9.5W TDP(Down) (6W SDP). You say for the cooling design target an OEM can aim and build their device for the SDP and not TDP? I thought for the cooling requirements the TDP is still the required target.

Atom works a bit differently. But for Ivy and Haswell, there's a steady-state power cap that can be defined anywhere in between the SDP and the TDP. There is only one register that defines the cap, so it can only be set to one value, and not both. If it is set to the SDP (or anything other than TDP), then the TDP is ignored. Your performance will range from whatever you can reach while in turbo operation, to whatever you can reach in steady-state operation. It depends on a value defined in another register, between 1 and 30 seconds. The timer begins as soon as a workload takes the CPU out of an idle or sleep state - but it's based on a decay model, so constantly taking the CPU in and out of idle (as in certain bursty scenarios) will not start the timer back at zero.