Power Consumption And Temperatures
Processor power-saving features were enabled on both stock configurations, including last quarter’s overclocked setup. But because the Pentium processor I'm using this time around is already such a low-power component, I didn't try to tune with EIST (Enhanced Intel SpeedStep Technology) enabled.
It's no surprise that a two-core Haswell-based CPU uses less power than AMD's 100 W Athlon X4. However, I didn't think that this quarter's overclocked configuration would need less power than last quarter's stock setup. Consumption while gaming is also down. Although you won't find this information in the chart, our new overclock peaks at just 197 W during a 10-minute Far Cry 3 sequence. That's 14 W less than last quarter's stock settings.
Other observations to note are the idle impact of disabling EIST, plus how little extra power is consumed under full system load (compared to the GPU-only measurement). 3DMark relies less on the host processor than our games, but still taxes one core (or in this case, half the Pentium’s available resources).
The peak CPU load temperature used for this calculation is the Pentium’s hotter-running core while stability testing in Prime95. Pushed to 1.238 V, a reasonable 72 degrees Celsius was lower than I imagined for the stock cooler. Even better, neither core climbed above 57 Celsius while playing Far Cry 3. Airflow from our enclosure’s three fans must have successfully helped the boxed heat sink do its job.
Last quarter, I had to use the motherboard’s CPU socket temperature readings for the Athlon X4 750K. However, my main focus while overclocking was directed towards Thermal Margins as reported by AMD OverDrive, which under load still indicated we had a reasonable cushion of 25 degrees Celsius.
As long as there is sufficient case airflow, our 10-minute burn test sitting outside Far Cry 3’s Amanki Outpost quickly heats the GPU up as much as an hour of normal gameplay. Although last quarter I ramped up cooling with a custom fan profile while overclocking, this Radeon R9 270 runs plenty cool at Sapphire's automatic fan settings, peaking at 44% duty cycle.
With our temperatures in check on both systems, the current PC's most pleasing feature is its low noise. Although Intel’s bundled thermal solution is the quieter of the two coolers, the largest noise-maker could have been mitigated last quarter by simply replacing or disconnecting the annoying side-panel fan. I only plugged that one in while overclocking to help keep my Athlon CPU cool.
