The Pentium 4 600 Series
|Pentium 4 600 Series|
|0||SSE3, TM2, HT, C1E, XD, EMT64|
A stepping update was introduced only three months after the release of the Pentium 4 570 at 3.8 GHz, the fastest processor of the 500 series. The so-called 600 series was also based on the Prescott core, but with doubled L2 cache. Upon its introduction, the fastest CPU of this new family was the Pentium 4 660 running at 3.6 GHz.
The die of the 600 series Prescott processors takes up 135 square mm².
Additionally, the 600 series came equipped with the EIST (Enhanced Intel SpeedStep Technology), XD, EM64T, and TM2 (Thermal Monitor 2) features right from the start. The 500 series, meanwhile, only gained these one at a time over a longer period. Hyper Threading also received a few small improvements in the new 600 series. Finally, Intel's validation of DDR2 memory with a CAS latency of 4.0 clocks was also welcomed.
At the same time, the Thermal Monitor 1 that had been introduced with the first iteration of the Prescott core was replaced with the much more intelligent version 2. It now allows work on the computer to continue normally; unlike Thermal Monitor 1, which skipped entire clock cycles to let the processor cool down, Thermal Monitor 2 simply lowers the CPU's internal clock speed. Thus, although the clock cycles are now longer, they are still more constant and don't result in choppiness in the system.
The operating principle of the Thermal Monitor 2: The resulting TM2-clock cycles continue to be regular, unlike that of the TM1.