Introducing PowerColor Radeon HD 7770 1 GB
Introduction
Launched amongst much fanfare earlier this year, It's now time for AMD's Graphics CoreNext architecture to get down to serious business: driving a mainstream GPU that offers killer value at price-points which most people will end up buying. AMD today launched the Radeon HD 7700 series, based on its spanking new silicon codenamed "Cape Verde".
What makes this launch a particularly monumental challenge for Graphics CoreNext is that it now has to deliver on its biggest design goal, that of being a more efficient number-cruncher than previous-generation VLIW architecture. This efficiency is supposed to show in relative performance per mm² (taking the new 28 nm fab process into account), performance per Watt, and in more layman terms, performance to stream processor count.
But first, a little history lesson. AMD addressed the sub-$200 market with its first DirectX 11 generation of GPUs using the Radeon HD 5700 series, based on the 40 nm "Juniper" silicon. Since the following HD 6000 series was also based on this process, and AMD had achieved higher performance targets with "Barts", it decided to reshuffle the higher-end lineup, give Barts the HD 6800 series, and since Juniper was the only GPU smaller than Barts, re-brand it to the HD 6700 series, to everyone's disgust including ours. With the transition to the new 28 nm fab process and a new number-chomping architecture, Graphics CoreNext, designing a new GPU became inevitable for AMD. Hence, Cape Verde. Products based on this chip, the Radeon HD 7770 and Radeon HD 7750, are touted to be true successors of the HD 6700 series.
We also have the following reviews for you today:
- AMD Radeon HD 7770 (reference design)
- HD 7750 & HD 7770 in CrossFire
- ASUS Radeon HD 7770 DirectCU Review (custom cooler & overclocked)
- HIS Radeon HD 7750 iCooler (custom cooler)
- MSI Radeon HD 7770 OC (custom cooler & overclocked)
- XFX Radeon HD 7770 Black Edition Super OC Review (custom cooler & overclocked)
Architecture
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. A command processor takes input from the host machine, decodes
them, and does the groundwork for the number-crunching area, the
Graphics CoreNext clusters, which then perform all the shader and
math-intensive processing. The Raster Operations area does the final leg
of the processing, and the information is forwarded to the display
logic. All components are interconnected to an L2 cache, that works as a
very fast scratchpad for the GPU, and of course, the memory
controllers.
Cape Verde has 10 Graphics CoreNext Computing Units (GCN CUs), which total up 640 stream processors. The chip has 40 TMUs, and 16 ROPs. It features a 128-bit wide GDDR5 memory interface, with which it communicates with 1 GB of memory. The chip retains the display logic of Tahiti, which lets you connect up to 6 displays in Eyefinity for productivity usage. The GPU also features PCI-Express Gen. 3.0 support, which increases bandwidth between it and the rest of the system. While we doubt the chip really needs 32 GB/s of system bandwidth, PCIe Gen 3.0 could come handy when connected in configurations with lower number of PCIe lanes (such as x8, x4, or even x1), as PCIe Gen 3.0 has more bandwidth per lane.
With the new HD 7000 series, AMD also introduced what it refers to as ZeroCore Technology. Simply put, this feature reduces power consumption of the GPU down to zero, by gating power to it, when the system is idling for extended periods of time, when the displays are blanked. In this power state, the graphics card draws less than 3W of power, making it extremely energy-efficient. The typical board power figures for the Radeon HD 7700 GPUs are also claimed by its makers to be extremely low.
Cape Verde has 10 Graphics CoreNext Computing Units (GCN CUs), which total up 640 stream processors. The chip has 40 TMUs, and 16 ROPs. It features a 128-bit wide GDDR5 memory interface, with which it communicates with 1 GB of memory. The chip retains the display logic of Tahiti, which lets you connect up to 6 displays in Eyefinity for productivity usage. The GPU also features PCI-Express Gen. 3.0 support, which increases bandwidth between it and the rest of the system. While we doubt the chip really needs 32 GB/s of system bandwidth, PCIe Gen 3.0 could come handy when connected in configurations with lower number of PCIe lanes (such as x8, x4, or even x1), as PCIe Gen 3.0 has more bandwidth per lane.
With the new HD 7000 series, AMD also introduced what it refers to as ZeroCore Technology. Simply put, this feature reduces power consumption of the GPU down to zero, by gating power to it, when the system is idling for extended periods of time, when the displays are blanked. In this power state, the graphics card draws less than 3W of power, making it extremely energy-efficient. The typical board power figures for the Radeon HD 7700 GPUs are also claimed by its makers to be extremely low.
PowerColor HD 7770 1 GB
PowerColor sent us a card that is pretty much identical to the AMD reference design. Only the cooler has undergone very minor changes on the outside. Its internals are the same as on the AMD board, clock speeds are also at reference design level.
Packaging
Contents
You will receive:
- Graphics card
- Driver CD + Documentation
- Analog VGA Adapter
- Mini-DP to DP Adapter
The Card
PowerColor has chosen to use the same heatsink as on the AMD reference design, with slightly different branding on the outside.
The card requires two slots in your system.
Display connectivity options include one DVI port, one full size HDMI port and two mini-DisplayPorts. 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
PowerColor's thermal solution uses a rather simple approach that works without heatpipes or a fancy copper plate.
The card requires a single 6-pin PCI-Express power cables for operation. This power configuration is good for up to 150 W of power draw.
For voltage control the card uses the ST L6788A chip, which is the same as on many HD 5770 models. While it does offer software voltage control it severely lacks in the overclockers department. For example, it is not possible for software to read the current voltage, unless the chip is running on manual voltage mode (which is not the case when the card is at stock, with stock drivers).
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:www.techpowerup.com
