IBM CMX58886CX user manual Thermal Monitor and Thermal Throttling, Error-Correction Codes

Thermal Monitor and Thermal Throttling

The Intel ® Thermal Monitor is a feature on the CMX58886CX that automatically throttles the CPU when the CPU exceeds its thermal limit. The maximum temperature of the processor is defined as the temperature that the Thermal Monitor is activated. The thermal limit and duty cycle of the Thermal Monitor cannot be modified. The Thermal Monitor can be disabled by the BIOS for applications where deteministic speed is more important than device failure due to thermal runaway. In addition to the Thermal Monitor, conventional Thermal Throttling is also provided. This forces the CPU to skip clock cycles when it exceeds a thermal limit. The thermal limit and duty cycle of thermal throttling can be modified in the BIOS.

Error-Correction Codes

The Graphics and Memory Controller Hub (GMCH) may be configured in the BIOS setup to operate in an Error-Correction-Code (ECC) data integrity mode. ECC mode allows multiple bit error detection and single bit error correction. The GMCH generate an 8-bit code word for each 64-bit Qword of memory, and performs a full Qword write at a time so that an 8-bit code is sent with each write. Since the code word covers a full Qword, writes of less than a Qword require a read-merge-write operation. Consider a Dword write to memory. In this case, when in ECC mode, GMCH will read the Qword where the addressed Dword will be written, merge in the new Dword, generate a code covering the new Qword and finally write the entire Qword and code back to memory. Any correctable (single-bit) errors detected during the initial Qword read are corrected before merging the new Dword.

Memory with ECC enabled requires additional system memory resources. This will cause the integrated graphics engine to have less memory bandwidth for access to the graphics frame buffer. Because of this, the display may flicker at high resolutions when the graphics processor is fully utilized and ECC is enabled. ECC memory is supported with internal graphics only.

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