AMD Radeon HD 7790 Revealed



Product: AMD Radeon HD 7790
Company: AMD
Author: James Prior
Editor: Charles Oliver
Date: March 21st, 2013

Introducing Bonaire

Today the veil lifts on a new GPU from AMD, codenamed Bonaire. Bonaire is an island in the Caribbean, and is AMD's latest Sea Islands 2013 product group GPU, the AMD Radeon HD 7790. There are a lot of islands in the sea - lots of seas, for that matter - and so the fair isle of Bonaire fits nicely into the Southern Islands stack between Cape Verde and Pitcairn. The AMD Radeon HD 7790 doesn't feature a new architecture - this is a Graphics Core Next (GCN) architecture with no revisions. Bonaire has some configuration enhancements, and process maturity tweaks, to give it a boost over the Radeon HD 7700 / Cape Verde series without blowing up the power budget - this is the first GPU to learn from AMD's APU products; AMD explicitly stated Richland, but we have suspicions about a certain semi-custom design, too.

AMD Radeon HD 7790

Four numbers stand out with the Radeon HD 7790 / Bonaire: the number of GCN compute units (14, up from Cape Verde's 10) which naturally increases texture units as well (4 TMUs per CU). Next is the clock speed of the engine, the reference clock is 1GHz like Cape Verde but both partner samples from Sapphire and Gigabyte feature a 7.5% factory overclock for a 1075MHz as tested speed. The third number is memory clock, a full 1600Mhz / 6Gbps like on the big boys GPUs for 96Gbps bandwidth. Finally, there's the primitive per clock rate, now set at two per tick - also like the big boy GPUs (Pitcairn and Tahiti), the Bonaire design leverages dual Asychronous Compute Engines to increase geometry throughput.

GCN ASIC's

Bonaire features ~40% more transistors than Cape Verde, hitting the magic 2bn number, actually 2.08Bn - not far shy of the 2.15Bn in the 2009 flagship HD 5870 / Cypress GPU. At 85W board power. Yeah. A 5W increase over the HD 7770 Ghz Edition with a healthy bump on every spec, which AMD performance figures indicate could increase performance by almost 30%. 30% more from 5W. This is part of the trick learned from the APU, a result of the refinements of Trinity to create Richland, which led to the new voltage changing abilities, which leads to a total of eight digital power modes (DPM). The original HD 7000 series has 3 DPM states, and Boost enabled parts have 4 DPM states.

DPM States

AMD Radeon HD 7790 Specifications:

  • 28nm Graphics Core Next architecture using 2.08Bn transistors
  • 896 Stream Processors in 14 Compute Units (CU)
  • 1000Mhz Engine Clock
  • 1500MHz (6Gbps) 1GB GDDR5
  • 128-bit Memory Bus
  • 96GB/s memory bandwidth
  • 56 Texture Units
  • 16 ROPS
  • 1.79 TFLOPS (Single Precision)
  • DVI-DL + HDMI 1.4 & 2 mini-DisplayPort outputs
  • Supports Fast HDMI and Positional Audio
  • DirectX 11.1 / OpenCL 1.2 / OpenGL 4.2 / C++ AMP
  • 85W Board Power limited by PowerTune
  • 6-pin PCI-E power input
  • <3W Idle power under ZeroCore Power
  • PCI-Express 3.0
  • $149USD SEP

From the outset, AMD partners will be launching custom designs with their own PCBs and coolers. We have two such cards for testing today, the Sapphire Radeon HD 7790 Dual-X OC and the Gigabyte Radeon HD 7790 GV-779OC-1GD. Both cards feature custom heatsink and fan designs, and factory overclocks. Below you can see more of the partner offerings:

Sapphire Dual-X OC
Gigabyte OC
ASUS
PowerColor Turbo Dual
Sapphire
PowerColor