Judging by details revealed in a chip conference agenda, the clock frequency race isn't over yet. IBM's Power6 processor will be able to exceed 5 gigahertz in a high-performance mode, and the second-generation Cell Broadband Engine processor from IBM, Sony and Toshiba will run at 6GHz, according to the program for the International Solid State Circuits Conference that begins February 11 in San Francisco. Chipmakers have run into problems increasing chip clock speed--essentially an electronic heartbeat that synchronizes operations in a processor--because higher frequencies have led to unmanageable power consumption and waste heat . To compensate, Intel and Advanced Micro Devices have turned instead to the addition of multiple processing cores on each slice of silicon. That's effective when computers are juggling numerous tasks at the same time, but increasing the clock speed means an individual task can run faster. The first-generation Cell Broadband Engine chip,...