Introduction

AMD announced its first new desktop graphics product for the year, the Radeon HD 7790. The company recently made it clear to us that it won't be introducing a new GPU family any time soon, at least not before October, but that doesn't mean it can't do patchwork to its existing product stack. The company seems least bothered with NVIDIA's recent GTX Titan Launch and finds that its "Never Settle Reloaded" bundles give its products an edge over NVIDIA's offerings, and with a bouquet of game titles under development that are optimized for its GPUs, things look like smooth sailing. In all the noise, AMD conveniently neglected the sub-$200 market.



The $100-200 market segment is a particularly high-volume one. AMD's current offerings include the Radeon HD 7850 1 GB around $179, the Radeon HD 7770 GHz Edition at $109, and practically nothing in between, unless you want to buy near-EOL new old-stocks of previous-generation AMD offerings such as the Radeon HD 6870. NVIDIA targeted this gap with its GeForce GTX 650 Ti aptly priced at $149 (now $139). The HD 7770 GHz Edition may convincingly beat the GTX 650 (non-Ti), but is too underpowered in comparison to the GTX 650 Ti. Playing current games at 1080p using the HD 7770 is asking for much.

AMD finally got down to do the patchwork, but may have realized that its 2.8 billion-transistor "Pitcairn" GPU can't be sold at price points lower than what the HD 7850 1 GB commands, and it could certainly not offer any cushioning for further price-cuts. AMD's solution? Build "Bonaire," a spanking new ASIC with just 2.08 billion transistors, but with a clever component layout. The chip allows AMD to price the Radeon HD 7790 exactly at $149, with room for future price-cuts.



Built on the 28 nm silicon fab process, Bonaire's component hierarchy has more in common with "Pitcairn" and "Tahiti" than with "Cape Verde," although all four are based on AMD's Graphics CoreNext micro-architecture. It features 14 compute units, which work out to 896 stream processors, two independent geometry engines, and two rasterizers. In comparison, Cape Verde may have 10 compute units (640 stream processors), but just the single geometry engine and rasterizer. AMD's approach with Bonaire may yield dividends with tessellation performance, so enabling tessellation shouldn't tax the GPU as much. AMD didn't widen the memory bus any further than 128-bit, but took advantage of falling 7 GT/s chip prices to clock the memory at 6.00 GHz (GDDR5 effective), which yields 96 GB/s of memory bandwidth (a 33% increase). The core remains at 1.00 GHz, but is augmented with an improved dynamic clock technology.



The new dynamic clock technology, which AMD no longer refers to as "boost," promises higher sustained clock speeds and better energy efficiency. The core clock speed mentioned by AMD in its specs sheets, 1.00 GHz, is the GPU's maximum (unless you manually overclock), which most applications shouldn't have a problem accessing. An improved dynamic-clock algorithm gauges graphics processing load, power limits, and temperatures at a higher polling rate of 10 ms, switching the clock speed, as needed, between 8 power states.



In this review, we're testing Sapphire's premium implementation of the Radeon HD 7790 featuring the company's Dual-X cooling solution. The card features a custom-design dual-fan cooler and offers factory-overclocked speeds of 1075 MHz core and 6.40 GHz memory for a premium of just $10 over AMD's suggested reference design retail price of $149.

Packaging

Contents

You will receive:

• Graphics card
• Driver CD + documentation
• PCI-E power cable
• DVI adapter
• CrossFire bridge
• HDMI cable

The Card

Sapphire is using the same dual fan cooler that we've seen on their HD 7850 Dual-X before. Note how short the actual PCB in the second picture would be. There is lots of unused space to the left, but keeping the length makes sense to for optimal airflow.


Installing the card requires two slots in your system.


Display connectivity options include two DVI ports, one full-size DisplayPort, and one full-size HDMI port. You may use all outputs at the same time, so triple-monitor surround gaming is possible with one card. The difference between the white and black DVI connector is that the white one carries an analog VGA signal.

The GPU also includes an HDMI sound device. It is HDMI 1.4a compatible, which includes HD audio and Blu-ray 3D movies support.


A single CrossFire connector is available, which means you can pair up two Radeon HD 7790s in a multi-gpu configuration.


Pictured above are 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.