- Gigabyte F2A88X-UP4
- 16GB Kingston DDR3 Savage 2400Mhz Ram (Review)
- Sapphire R9 285 Dual X OC 2GB
- Noctua NH-D15S (Review)
- TP-LINK TL-WR841HP Wi-Fi Router (Review)
- Asus MG279Q 1440p Gaming Monitor
- 1TB Western Digital HDD
- OCZ ZS 650 PSU
- Windows 8.1
Special Thanks to:
- AMD for the A10-7870K
- AMD for the Gigabyte F2A88X-UP4
- AMD for the Sapphire R9 285 Dual X OC 2GB Crossfire
- AMD for the Asus MG279Q Gaming Monitor
- Kingston for the 16GB DDR3 Savage 2400Mhz Ram
- Noctua for the NH-D15S
- TP-LINK for the TL-WR841HP Wi-Fi Router
Overclocking and Undervolting
Overclocking is the process of increasing the clock frequency beyond the recommended speeds set by the manufacturer. Increasing the clock speed will definitely lead to significantly higher performance. However, when increasing the CPU clock speed voltage will have to be increased to ensure the stability of the overclock. While overclocking we decided to turn off Turbo Boost as well as APM Master. APM Master is known for causing throttling on a software level. The Motherboard that we used for overclocking the A10-7870K was the Gigabyte F2A88X-UP4 Rev 3.0. The motherboard was already flashed with the latest bios, F7, enabling immediate support for the A10-7870K. The stock CPU voltage was unusually high set at 1.48v but reports of that happening has proven to be a direct result of an early bios release. Since the voltage can be reduced within the bios itself, this doesn’t prove to be a problem at all. We decided to test stability with Intel Burn Test (IBT) as it is commonly known to generate a lot of heat. Intel Burn Test was left running at it’s maximum for a good 30 rounds. All the overclocks seen in the chart below ran without any errors or reboots, thus ensuring that our results were stable. Since a lot of popular software monitoring tools weren’t accurate with temperature readings we decided to use AMD Overdrive. The Thermal Margin within AMD Overdrive is the most accurate when it comes to temperature readings of the A10-7878K. Thermal Margin indicates the temperature left for the CPU to reach it’s maximum safe operating temperature.
The chart above shows the clocks we were able to reach at the corresponding CPU voltages. The sweet spot seemed to be 4.5Ghz at 1.44v. We did manage to reach 4.7Ghz at 1.49v. In order to reach these overclocks we made use of the Noctua NH-D15S. Even at 4.7Ghz at 1.49v, we still had a whooping 33c showing in the Thermal Margin of AMD Overdrive indicating that it was 33c away from hitting the maximum safe operating temperature. The stock cooler which comes with the A10-7870K is an improvements over the one that was being sold along with the A10-7850K. However, we do not suggest overclocking on the stock cooler beyond 4-4.1Ghz depending upon the silicon of one’s chip. Temperature with the stock cooler rose steadily as we kept increasing voltage. The stock cooler is best left for stock clocks. On the iGPU side of things we were able to overclock it from 866Mhz all the way to 1040Mhz. That’s a 174Mhz overclock on the iGPU. To ensure stability we further increased the NB Voltage from 1.26v to 1.33v. The A10-7870K is an improvement over the A10-7850K in terms of overclocking. Even though its only ahead by a little, it nevertheless is ahead, suggesting that AMD did improve upon the manufacturing process.
The stock Ram speed compatible with the A10-7870K is 2133Mhz but can go all the way upto 2400Mhz via AMD Memory Profiles in the bios. For some reason we couldn’t stabilize the Memory speed at 2400Mhz and decided to use it at 2133Mhz. We believe that this issue has less to do with the APU and more to do with the motherboard as there have been quite a few reports of the inability to run 2400Mhz on a Gigabyte FM2+ motherboard.
Since the stock voltage was set at 1.48v owing to the bios of the motherboard, we decided to see by how much we could actually reduce the CPU voltage to run stock clocks. We continued to undervolt and managed to reduce the CPU voltage all the way to 1.2v for 3.9Ghz. This is tremendously impressive and may prove to be vital in reducing power consumption. Note that undervolting isn’t reducing performance as the CPU stock speed is still maintained. Undervolting also reduces temperatures and results in the same performance that one would get by running their CPU at 3.9Ghz at 1.48v.