SMP Windows On Laptops with Intel SpeedStep
Leonardo
Wake up and smell the glaciersEagle River, Alaska Icrontian
Previously, my laptop, Dell Inspiron E1405, C2D, T2400, 1830MHz/core, 1GB DDR2 performed very well with two clients running Folding@Home (standard cores). I switched to SMP Windows and observed some strange activity by SpeedStep, the Intel programming that throttles a CPU up to 50% to preserve battery strength and save energy.
The problem was that even when SMP Folding was utilizing the processing power of both cores at near 100%, after folding for an hour or two, the CPU would throttle down to 50% clock rate, effectively stalling SMP Folding. I tried several different BIOS settings for both SpeedStep and C-State settings, all to no avail. If I did not have something running on the laptop in addition to SMP Folding, the CPU core speed would drop to 50%. And yes, I am referring to running on AC power.
Solution: They only way I was able to get around this was to set the screensaver to come on when I am not using the laptop. This way, SpeedStep does not force 50% core clock, and the computer Folding will continue to supported by 100% CPU utilization.
The monitoring tools I used track CPU utilization and laptop Folding production are FAHMon and CPU Z. I would encourage all C2D laptop SMP Folders to closely monitor their laptop's CPU frequency and Folding production.
The problem was that even when SMP Folding was utilizing the processing power of both cores at near 100%, after folding for an hour or two, the CPU would throttle down to 50% clock rate, effectively stalling SMP Folding. I tried several different BIOS settings for both SpeedStep and C-State settings, all to no avail. If I did not have something running on the laptop in addition to SMP Folding, the CPU core speed would drop to 50%. And yes, I am referring to running on AC power.
Solution: They only way I was able to get around this was to set the screensaver to come on when I am not using the laptop. This way, SpeedStep does not force 50% core clock, and the computer Folding will continue to supported by 100% CPU utilization.
The monitoring tools I used track CPU utilization and laptop Folding production are FAHMon and CPU Z. I would encourage all C2D laptop SMP Folders to closely monitor their laptop's CPU frequency and Folding production.
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