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Wednesday, March 21, 2012

Gigabyte HD 7770 OC

A few weeks ago AMD launched their Radeon HD 7700 Series. The cards use the all-new Cape Verde graphics processor which is based on AMD's new GCN Graphics Core Next architecture that promises increased performance and lower power draw.

Cape Verde is a downscale from the "Tahiti" silicon, on which higher Radeon HD 7900 series parts are based. There are fewer number of redundant components, so Cape Verde is left functionally-identical to Tahiti, but is smaller, built for more affordable graphics cards. Cape Verde also retains the basic hierarchy of the architecture as implemented in Tahiti.
Gigabyte's HD 7770 OC is a custom implementation of the HD 7770. It features a massively increased GPU clock speed of 1100 MHz. Memory clock has been increased too, to 1250 MHz.

Radeon HD 7770 Market Segment Analysis

HD 7750
GTX 550 Ti

GTX 460
GTX 460

HD 7770
Gigabyte HD
7770 OC
GTX 560

Shader Units




Graphics Processor

Cape VerdeGF116

Cape VerdeCape VerdeGF114


Memory Size

1024 MB1024 MB

768 MB1024 MB
1024 MB1024 MB1024 MB
Memory Bus Width

128 bit192 bit

192 bit256 bit
128 bit128 bit256 bit
Core Clock

800 MHz900 MHz

675 MHz675 MHz
1000 MHz1100 MHz810 MHz
Memory Clock

1125 MHz1026 MHz

900 MHz900 MHz
1125 MHz1250 MHz1002 MHz


$160$160$170E CARD

Gigabyte's card uses the samae cooling solution as their HD 6770 and GeForce GTX 550 OC. The heatsink uses a very large 10 cm fan to provide maximum airflow to the card.

The card requires two slots in your system.

Display connectivity options include one DVI port, one full size HDMI port one full size DisplayPort. You may use all the outputs at the same time, thanks to AMD's superior display output architecture.

An HDMI sound device is included in the GPU, too. It is HDMI 1.4a compatible which includes HD audio and support for Blu-ray 3D movies. The DisplayPort outputs are version 1.2 which enables the use of hubs and Multi-Stream transport.
You may combine up to two HD 7770 cards from any vendor in a multi-GPU CrossFire configuration for higher framerates or better image quality settings.


Pictured above are photos of the front and back, showing the disassembled board. High-res versions are also available (front, back). If you choose to use these images for voltmods etc, please include a link back to this site or let us post your article.


Gigabyte's heatsink uses a fairly standard approach to cooling. A large metal piece with fins sits on top of the GPU core and soaks up the heat. The large fan on top of it blows air across the fins to transport heat away efficiently.
The card requires a single 6-pin PCI-Express power connector. This configuration is good for up to 150 W of power draw.
An uPi uP1609 is used to generate the GPU voltage. I've never seen that controller before, so it is unknown whether it supports software voltage control.
The GDDR5 memory chips are made by Hynix, and carry the model number H5GQ2H24MFR-T2C. They are specified to run at 1250 MHz (5000 MHz GDDR5 effective).
AMD's new Cape Verde graphics processor introduces a new shader architecture, it is also the second GPU to be produced on a 28 nm process at TSMC. The transistor count is 1.5 billion.