ONLY THERMAL CORRECTNESS CAN ELIMINATE CPU THROTTLING

As a self-protection feature, some CPU's incorporate an internal temperature monitoring diode and a throttling circuit. In simple terms, you can think of this as a thermally controlled governor. The governor in this case wields a two-edged sword. On the plus side, the governor will prevent the CPU from overheating to the point of system failure, and thus provides for a stable system even when built into a thermally sub-standard chassis. On the minus side, the governor limits the performance of any such system by automatically lowering the CPU speed. In other words, while you get a stable system regardless of the thermal performance of the chassis, you don't "get what you pay for". The really sad thing about this situation is that you have no way of knowing if and how much your system performance has been compromised and performance-monitoring software is no help, because it will of course report that the CPU is fully occupied. While there is undeniable value in having a stable system, we at CCSI feel that insuring system reliability by "hobbling" system performance is a bit like harnessing a racehorse to a sightseeing carriage or perhaps in an extreme situation to a plow. While the racehorse certainly could pull the carriage or the plough, that is not what he was born and bred for!

CPU's that do not have the throttling feature always run at full speed, but require a chassis that provides proper cooling in order to run reliably. The advantage of a thermally correct chassis is that it will not only allow a non-throttled CPU system to run reliably, but will also allow a throttled CPU to run without the governor being invoked, thus optimizing both system reliability and performance.

As can be seen from the above discussion, it is critical when purchasing a chassis to make sure that it is thermally correct in order to avoid CPU throttling. Any statement to the effect that "we have the system running at such and such speed with no problem" should be taken with at least a "grain of salt". Since the system, while operating reliably, may not truly be "running", but "walking" or even "crawling".

Power supply design for 1U and 2U servers is another extremely challenging task due to several opposing design criteria. On the one hand we must provide more power for the higher speed dual CPU processor servers and on the other hand we have far less physical space available for the power supply plus we have to contend with the thermal issues described above. Increasing power output while significantly reducing the size, and providing the required thermal management of high output 1U power supplies is a daunting task, which is well beyond the abilities of the average conventional designer. In fact, with experienced engineering staff with many years of experience in designing high density systems and solving thermal management challenges, CCSI still spent over 2000 man-hours on these solutions and went through three different power supply designs to arrive at the final dual 300 watt power supply utilized in our RC 0103 1U chassis.

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