Sapphire HD 7970 6GB Vapor-X GHz Edition Reviewccokeman -
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What you get when you step up to the Sapphire HD 7970 6GB Vapor-X Edition is a card that appears visually to be a carbon copy of the next level up Toxic Edition card from Sapphire. The small difference in appearance is by way of the Vapor-X stickers instead of the Toxic Edition stickers on the hub of the dual sealed fans. The most identifiable feature of the card is the large dual fan-equipped Vapor-X cooling solution. Sapphire's HD 7970 6GB Vapor-X Edition is built from a base that includes AMD's 28nm Graphics Core Next architecture for use in a PCIe 2.0/3.0 16x slot. At 11 inches in length, the card should fit within the confines of most of the mid/full towers on the market. The Vapor-X cooling solution is going to occupy 2.5 slots and may interfere with running a CrossfireX setup on some motherboards.
From the front the large cooling solution takes center stage with the Vapor-X logo strategically placed on each fan hub. The rear view shows a full cover back plate that functions as both a brace for the 12 layer custom PCB and as a heat sink for the 3GB of GDDR5 memory that sits on the back of the PCB. The Vapor-X logo is present in a bold text that will be visible through a chassis window. Cutouts in the back plate open around large components including the back half of the ten phase power circuit using Black Diamond chokes that run 10% cooler and 25% more efficient than reference designs. The bottom view shows that the cooling solution employs four heatpipes that transfer the thermal load from the vapor chamber base to the fin array. Along the top of the card is the Sapphire logo that lights up white when the card is in operation.
Connectivity options for the Sapphire HD 7970 6GB Vapor-X Edition includes the standard for the HD 79XX series pair of Dual Link DVI ports, a single HDMI 1.4a port that offers support for Deep Color, 7.1 High Bitrate Audio, and Stereoscopic 3D, and a pair of Mini Displayport 1.2 ports that support the use of an MST hub or daisy chaining DisplayPort monitors to allow the card to support up to six displays in an Eyefinity setup. Eyefinity 2.0 brings along the ability to have independent audio streams for each video so you can have independent video streams with audio that follows along with each one. The venting on the I/O bracket is not going to allow a ton of air through it but will help to discharge a percentage of the thermal load while the rest will be recycled into the chassis airstream for removal by the case fans. Most modern chassis have adequate airflow to minimize the effects of the open shroud design dumping heat into the chassis. The back view shows part of the VRM circuit and the voltage control and monitoring chip. The dual cooling fans are connected to separate headers on the 12 layer PCB instead of connecting to single header and splitting up under the shroud.
Along the spine of the card are some of the interesting features of the HD 7970 6GB Vapor-X Edition. Dual Crossfire bridge connections allow up to four cards to be connected in a CrossfireX configuration using a motherboard that supports this feature. The large Vapor-X cooling solution will make this configuration a difficult proposition but using the cards with a water cooling system you can enjoy a quartet of these cards. Just under the Crossfire Bridge connections is a series of LEDs used to indicate the temperature state of the GPU with green, amber, and red LEDs as a visual clue as to how warm the GPU core is getting. The HD 7970 had a dual BIOS switch mounted just aft of the CrossfireX connections that allowed the end user to have two BIOS profiles to switch back and forth as need be or to recover from a bad flash. On the GHz Edition cards that feature a boost clock the switch still functions much the same but allows for an increased clock speed. Stock GHz Edition cards have a stock clock speed of 1000MHz on the core and a dynamic boost clock of 1050MHz. The EZ OC button jumps the base clock to 1050MHz with a dynamic boost clock of 1100MHz. When activated this button glows a bright Sapphire Blue. The true test of its worth is a boost in gaming FPS or benchmarking results. In this respect it offered an increase in my 3DMark 11 results of close to 300 point at the performance preset. Dual 8-pin power connections show that a 375 watt draw is possible when you take into account the 75W coming from the PCIe slot. Minimum power supply requirements for using this card is a 500 watt power supply with an 850 watt PSU suggested for CrosfireX configurations.
Peeling off the heat sink and back plate allow us to get a closer look at what makes up the Sapphire HD 7970 6GB Vapor-X Edition. As large as the vapor chamber and heat pipe based cooler is, it is held on by only the four screws around the GPU core socket. The back plate is held on with more screws as it is used to provide structural rigidity for the PCB, as well as doubling as the heat sink for the back half of the power circuit and the 3GB of GDDR5 memory on the back. Just like the Toxic Edition, the PCB shows as jet black under a flash instead of a dark brown providing some visual appeal. Along the top of the PCB are a series of voltage check points that can be used when the blue cover over them has been removed and provide a useful access point for monitoring leads.
Sapphire uses its Blue Power+ 8+1+1 power circuit that includes an 8+1+1 phase power circuit running through a 12 layer PCB. Eight phases feed power to the CPU core with another dedicated to the memory and MVDD circuit. Used on both the Toxic Edition and the 6GB Vapor-X Edition are new double sided Black Diamond chokes and DirectFET technology that work to reduce operating temperatures of this part of the system by as much as 40 °C. Additional cooling comes by way of small heat sinks attached to the PCB. These cover the power circuits and are cooled from the airflow through the heat sink to keep the thermals in check. A CHIL CHL8228 controller is used to provide software based voltage control and monitoring.
As the main feature of this card the cooling solution bears a large percentage of the focus. Sapphire has put together a dual 90mm fan equipped vapor chamber design that uses four heat pipes (two 8mm in size and two at 6mm) to carry the thermal load from the vapor chamber plate to the aluminum fin array. An industrial looking shroud is mounted over the heat sink assembly for both looks and functionality. This new Vapor-X vapor chamber is designed specifically for this current generation of Vapor-X-equipped cards. The vapor chamber uses a stepped surface to mate with the core due to the shim used around the core. As seen on the Toxic and 3GB Vapor-X, a pair of small aluminum sinks are used to cool the power circuits and fit under the main thermal solution.
A pair of 90mm fans are used to drive the airflow through the thermal solution on this Vapor-X-equipped HD 7970 . Made by FirstD these fans are 90mm in size, PWM controlled, and feature an aerofoil fin design and hubs that are designed to be dust resistant, improving longevity of both the fans and the card. When run at maximum speed these fans are audible in the case. As fan speed is reduced the noise generated decreases to a point where the card is inaudible. While PWM controlled, the fans were incredibly quiet in comparison to a reference design.
AMD's GHz edition 28nm Tahiti core is just an improved process core that features the same GCN architecture and specifications as the non GHz edition parts with the exception of the Dynamic boost feature for the GPU core. Transistor count is 4.31 billion, stream processor count is 2048, texture units at 128, and ROPs at 32. GDDR5 memory is used on the HD 7970 6GB Vapor-X Edition and runs through a 384-bit bus. Hynix is the supplier of choice with its 1500MHz rated H5GQ2H24AFR-R0C modules, 24 of which are used to make up the 6GB frame buffer size on this 6GB-equipped card. The GHz Edition core is rated to run at 1000MHz with a dynamic boost clock of 1050MHz. Sapphire's EZ OC button adds 50MHz to the base clock to 1050MHz with a dynamic boost clock of 1100MHz with the push of a button. Memory speeds are left untouched at 1500MHz (6000MHz Effective) when in EZ OC mode.
Solidly built and equipped with the best Sapphire has to offer in terms of component selection and build quality, the HD 7970 6GB Vapor-X Edition should provide a challenge for the further upscaled Toxic edition. Let's see how it compares to the competition.