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Intel's DG45FC "Fly Creek" industrial-sized (mini ITX) motherboard is a perfect HTPC motherboard - supporting desktop-class Intel Core 2 CPUs and having G45 chipset, capable of decoding Blu Ray content in real time thanks to hardware video acceleration implemented onboard. Unfortunately, motherboard's BIOS is very limited in terms of "advanced" options, namely the CPU voltage control, making undervolting and reducing power of CPU very hard, unless the user is very proficient in hardware engineering and able to "mod" the motherboard's power delivery circuitry.

Fortunately, this motherboard does not limit software control of CPU voltage at all - which makes is very similar to traditional laptop systems. With CPUgenie, we are able to easily control and reduce the voltage and power consumption of the HTPC setup based on Intel DG45FC.

- Motherboard: Intel DG45FC 'Fly Creek' G45 motherboard

- CPU: Intel Pentium Dual Core (Penryn core) E5200 'SLAY' 2500 MHz

- RAM: 2GB DDR2 800 MHz RAM

- OS: Microsoft Windows Vista, 32-bit

- ACPI BIOS contains processor performance records for two frequencies only (1200 MHz and 2500 MHz)

- Suggested voltage for 1200 MHz is 1.025V while the suggested voltage for 2500 MHz is 1.137V

This is rather "poor" configuration but in line with what you will get with most desktop board ACPI BIOS-es, unlike notebooks and mobile Core 2 Duo processors where there are typically several performance levels defined in ACPI BIOS. This also means that Windows CPU driver can only use these two configurations for performance management.

CPUgenie, on the contrary, is able to recognize and use all multipliers and performance levels, and also reduce the voltage in order to save power. We run the “Voltage Optimization Wizard” and after approx. 6 hours CPUgenie found much better values than factory defaults:

We also measured the power draw at the wall AC outlet, comparing the 100% load scenario of default system configuration and the same system running with CPUgenie optimized voltages:

Great results! It appears that our E5200 CPU is able to run at minimum allowed voltage, 1.025V on all multipliers - this, as a result, can save us up to 20 degrees Celsius under full load on 2500 MHz!!! For a HTPC system this is very significant temperature drop, which could enable more discrete cooling with less fan noise! Furthermore, we managed to save 17.8W of power (when system is running under 100% load) by purely decreasing the voltage of the CPU! On top of temperature savings, those power savings are also friendly to your power bill!

This also shows the potential of Penryn CPUs - running fully stable at 2500 MHz @1.025V probably means that the CPU could run stable at much lower voltages, pretty much as mobile Penryns do. Unfortunately, desktop Core 2 Duos are "VID-locked" preventing getting lower than a hard-coded minimum VID, 1.025V in the case of our E5200. CPUgenie also supports setting of any arbitrary VID (by "unlocking" the voltage range) but this typically has no effect as the limitation is hardware-based. You would need a special "Engineering Sample" (ES) version of the CPU in order to run it at any VID. Despite those limitations, this test shows that DG45FC with E5200 is an excellent HTPC board for software undervolting without any sacrifice of the performance!