Well, I've got another one to add to the 46th page of this awkwardly-long thread... For lack of a thread-search function, and having spent a disproportionate amount of time thumbing through several pages of this thread looking for it, I've got to ask...
Why does Phoenix (or by relation, poclbm, since I only have nVidia cards) use a full core's CPU, to no useful purpose? The only way I can efficiently use Phoenix - which is otherwise the most efficient client I've seen yet - is by tweaking Windows' power management settings to throttle the CPU to its minimum speed. If I allow Windows to run normal power management, Intel Turbo Boost kicks in on my laptop and runs the CPU full-blast... but it performs at
exactly the same speed (I've even seen marginally better!) when I throttle the CPU to its lowest (50%, verified with TMonitor) setting. In other words, Phoenix seems to be performing absolutely zero productive work with the full CPU core it eats up at any clock rate... meanwhile it produces twice the heat and consumes twice the power that it needs to operate!
This also serves as a useful tip for passers-by in this thread: for the energy-conscious, you can go to Windows' Power Options control panel, create a new power scheme (I call mine just "Bitcoin"), edit its advanced settings, and set Processor Power Management -> "Maximum processor state" to 50%... and you'll likely end up with half the wasted heat while maintaining the same performance in Phoenix
Sort of a dual-purpose post here: to explain this observation and its effects in hopes of finding a workaround or adding a fix in the code... and to see if anyone else experiences this same issue in their miners!
This has occurred for me in all of the following: Atom D510 with nVidia Ion (with clock tweaks, runs stable at 4.66 Mhash/sec), Core 2 Quad Q6600 with nVidia GeForce 8800GTS (tweaked, runs stable at ~22.5 Mhash/sec), Core 2 Duo with Quadro NVS 290 (stock, ~3Mhash/sec), and a Core i5 M430 with nVidia GeForce GT 325M (Optimus, tweaked, stable at ~12Mhash/sec). All running Windows 7 SP1 x64, all the latest drivers from nVidia.
edit to note: The 8800GTS and GT 325m both run as "add-on" GPUs; Optimus powers off the GPU when not needed and the 8800 is secondary to the Intel GPU in my setup. So I can throw desktop-responsiveness to the wind there - however, if I push "aggression" too far (varies with GPU), it crashes the display driver and I have to disable/re-enable the device to get clocks back to normal. Also has no effect on CPU usage. Any tweaks I could apply for these GPUs that aren't driving a display?