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

			Radeon HD 7750	GeForce GTX 550 Ti			GeForce GTX 460	GeForce GTX 460		Radeon HD 7770	Gigabyte HD 7770 OC	GeForce GTX 560
Shader Units			512	192			336	336		640	640	336
ROPs			16	24			24	32		16	16	32
Graphics Processor			Cape Verde	GF116			GF104	GF104		Cape Verde	Cape Verde	GF114
Transistors			1500M	1170M			1950M	1950M		1500M	1500M	1950M
Memory Size			1024 MB	1024 MB			768 MB	1024 MB		1024 MB	1024 MB	1024 MB
Memory Bus Width			128 bit	192 bit			192 bit	256 bit		128 bit	128 bit	256 bit
Core Clock			800 MHz	900 MHz			675 MHz	675 MHz		1000 MHz	1100 MHz	810 MHz
Memory Clock			1125 MHz	1026 MHz			900 MHz	900 MHz		1125 MHz	1250 MHz	1002 MHz
Price			$110	$120			$140	$140		$160	$160	$170

The 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.

A Closer Look

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.

Source: Techpowerup.com