GIGABYTE AMD A75 User Guide

GIGABYTE AMD A75 CHIPSET OC GUIDE

AMD Llano platform was launched recently and it offers some interesting overclocking abilities and impressive 3D
performance boost once system is tweaked. Llano platform has decent potential to make a great all rounder/home
media PC, office machine, even a gaming machine on a budget. We finally have an integrated GPU platform with some
solid graphics performance thanks to AMD and would like to share an OC guide!

The key to unlocking the potential of Llano platform is overclocking. GIGABYTE A-Series motherboard range has big
overclocking capability. The purpose of this guide is to show and analyse that overclocking capability and provide some
general pointers and key overclocking parameters, in order to get the most out of the platform to improve end user
experience.

Let's start with the test system used. High performance components were chosen purely for testing purposes and to
show capability of the platform rather than an indicative mainstream system, it's up to end users to combine what
price/performance components they wish to purchase.

SYSTEM:

 GIGABYTE A75M-D2H v1.0 (F3 shipping bios & F4c beta bios)
 AMD A8-3850 (quad core, 2.9GHz CPU, 600MHz GPU clock)
 4GB RAM KIT, Corsair CMGTX3
 8GB RAM KIT, Corsair CMGTX7
 750W Corsair HX750 PSU
 H100 Corsair water cooler
 Kingston SSDNow V Series 128GB SSD Drive (SATA0 port)
 ATI 11.7 Display Driver
 Windows 7 64-bit OS

The following benchmarks were used to assess performance and stability.

BENCHMARKS:

 3DMARK Vantage Performance
 SuperPi 8M
 Cinebench CPU
 Cinebench OpenGL
 Dirt3 game
 wPrime 32M

We chose a variety of CPU and GPU based benchmarks to try and understand how overclocking affects performance. In
terms of CPU based benchmarks we chose SuperPi 8M, wPrime 32M and Cinebench CPU which test single and multi
core performance. GPU based benchmarks include 3DMARK Vantage Performance, Cinebench OpenGL and Dirt3 DX11
video game.

These benchmarks are in no way a final test of stability and for further stability testing it is recommended to use some
form of CPU and GPU stress software. Ultimate stability is still the test of time.

Dino Strkljevic (dinos22), GIGABYTE Australia Page 1

BIOS screenshots

Dino Strkljevic (dinos22), GIGABYTE Australia Page 2

BASICS/KEY OC PARAMETERS

Max bclock: 161MHz frequency (bios settings)

Please be aware that current APUs are partially locked (locked upwards from max multi/frequency). This means that
even though a bios provides extra multipliers for CPUs or frequency adjustment on the GPU, they cannot actually set
CPU multi or GPU frequency higher than default values. In A8 3850 APUs case, the max multi is 29x and that is the
highest multiplier that can be set. A75M-D2H sees up to 47x multiplier however it will still default to 29x regardless of
what value is selected beyond 29x. Monitoring utilities may also show incorrect speeds to the real values in windows.
Best way to check is to test both settings and determine where there is any change in the benchmark. This board offers
GPU clock frequency change. Once again it is a locked APU and even though you can select frequency higher than 600 it
will not accept the change. You can however select lower frequency such as 550 or 500 which will reduce the GPU clock.
GPU frequency can only be changed to higher values via base clock adjustment on locked APUs.

How to OC Llano platform properly?

Reference Clock Adjustment

Given the fact APUs are currently locked the only way to properly overclock this platform is to control the reference
clock or base clock(bclock). Default value is 100Mhz and it can be adjusted upwards. Bclock will control CPU, memory
and GPU frequency. Increasing bclock to 110Mhz will increase CPU, RAM & GPU frequency by 10% for example. If we set
29x multiplier on CPU, x5.33 Memory ratio and 110Mhz bclock, the new CPU frequency will be 3190Mhz(29x110), RAM
frequency will increase from 1066MHz to 1172Mhz (110x5.33x2) and GPU frequency will increase from stock 600Mhz to
660MHz (600x1.10).

Our testing has two goals, to find the max bclock and to combine the max bclock with max CPU and memory frequency.

Dino Strkljevic (dinos22), GIGABYTE Australia Page 3