AMD Radeon R9 285 GPU Review: Tonga Arrives
Just about a year ago, AMD released the Radeon R9 290X, based on the GPU formerly codenamed Hawaii. At the same time, the company also re-jiggered and re-named the rest of its line-up to create a fresh, top-to-bottom line-up of graphics cards in the Radeon R7 and R9 series. The Radeon R9 290X, and eventually the R9 290 and R9 295X2, however, were the only cards to actually feature new GPUs (i.e. Hawaii). The rest of the Radeon R7 and R9 series products featured previously released silicon, though clock speeds and memory configurations were typically tweaked to help differentiate the products.
Today, however, AMD is launching a new mainstream graphics card based on another fresh GPU, codenamed Tonga. Typically, when the big GPU manufacturers launch a new high-end product, they pare that GPU down to create more affordable offerings with nearly identical feature sets. But Tonga is not simply a pared down version of Hawaii. AMD has actually updated and improved a couple of functional blocks in the GPU to boost performance and / or power efficiency.
The first product built around the Tonga GPU is the Radeon R9 285. As its name suggests, this card falls into AMD’s current line-up in between the Radeon R9 270X and R9 280X, but there’s more to the story than just that. Take a look at the Radeon R9 285’s specifications below, and then we’ll check out the card and dig into some numbers…
AMD’s reference specifications call for up to a 918MHz engine clock for the Radeon R9 285 with 1375MHz memory (5.5 Gbps effective). The specifications list 2GB of on-board memory, but 4GB variants are coming down the pipeline as well. Typical board power is 190W and cards require a pair of supplemental 6-pin power feeds. Support for Direct X12, Mantle, and AMD’s TrueAudio technology is also present. We’ll dig into some other details regarding the new Tonga GPU on the next page, suffice it to say there’s a lot more to Tonga than you may be expecting.
AMD’s reference cards look much like the rest of the R9 series, but the Radeon R9 285 we received for testing is a custom model from Sapphire. The Sapphire Radeon R9 285 Dual-X is outfitted with an oversized, dual-fan cooler, with a few beefy copper heat-pipes, and is slightly overclocked right out of the box.
The Sapphire Radeon R9 285 Dual-X has a GPU engine clock of up to 965MHz and 2GB of GDDR5 memory clocked at 1400MHz, for an effective data rate of 5.6Gbps. Memory bandwidth at that speed is up to 179.2GB/s, over the reference card’s 176GB/s. Like reference cards, this Sapphire model requires a pair of supplemental PCI Express power feeds.
Outputs on the card consist of a pair of DVI outs, an HDMI output, and a full-sized DisplayPort output. Of course, the Radeon R9 285 has full support for AMD’s Eyefinity multi-display technology, and it will also support upcoming FreeSync monitors, which are set to debut sometime early next year. FreeSync is AMD’s answer to NVIDIA’s G-Sync variable refresh rate technology.