IBM Intel Xeon E5504 46D1351 User Manual

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Intel® Xeon® Processor 5500 Series Datasheet, Volume 2

Parameters used by the thermal throttling logic.

Heat removed from DRAM 8 DCLKs. This should be scaled relative to the per command 
weights and the initial value of the throttling threshold. This includes idle command and 
refresh energies. If 2X refresh is supported, the worst case of 2X refresh must be 
assumed.

When there are more than 4 ranks attached to the channel, the thermal throttle logic is 
shared. 

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1

SAFE_INTERVAL. Safe values for cooling coefficient and duty cycle will be 

applied while the SAFE_INTERVAL is exceeded. This interval is the number of 

ZQ intervals since the last time the MC_COOLING_COEF or MC_CLOSED_LOOP 

registers have been written. A register to write to MC_COOLING_COEF or 

MC_CLOSED_LOOP will re-apply the normal MC_COOLING_COEF and 

MC_CLOSED_LOOP.MIN_THROTTLE_DUTY_CYC values. The register value 

written need not be different; writing the current value will suffice. The 

MC_THERMAL_STATUS.CYCLES_THROTTLED field is reloaded when the number 

of ZQ intervals exceeds this value. This field must not be programmed to 0; this 

value is illegal.

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255

SAFE_DUTY_CYC. This value replaces 

MC_CLOSED_LOOP.MIN_THROTTLE_DUTY_CYC while the 

MC_THERMAL_PARAMS_B.SAFE_INTERVAL is exceeded.

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1

SAFE_COOL_COEF. This value replaces MC_COOLING_COEF while the 

THERMAL_PARAMS_B.SAFE_INTERVAL is exceeded.

7:0

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0

ACTCMD_ENERGY. Energy of an Activate/Precharge Cycle.

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255

RANK3. Rank 3 Cooling Coefficient.

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255

RANK2. Rank 2 Cooling Coefficient.

15:8

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255

RANK1. Rank 1 Cooling Coefficient.

7:0

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255

RANK0. Rank 0 Cooling Coefficient.