The RX 480 has arrived for evaluation as an 8GB card. This is not the reference 4GB RX 480 with slightly slower vRAM that will sell for $199, but a more expensive $239 reference 8GB version. AMD has released its new Polaris architecture today and we are going to compare it to the GTX 980, to a mildly overclocked 970, and to the reference 290X and to the XFX 390 OC to see how this new card compares in performance and if it is well-suited for bringing less expensive VR to the masses as AMD claims.
According to AMD, the RX 480 graphics cards with Polaris Architecture and AMD LiquidVR technology deliver immersive VR experiences with leading VR headsets. But RX 480 is not just for VR as asynchronous shaders and new geometry capabilities enable support for DirectX 12 and Vulkan with the latest version of Graphics Core Next (GCN) for PC gamers. And gamers will be able to stream and record their favorite games up to 4K at 60 FPS with virtually no performance impact.
Polaris architecture combines the latest FinFET 14 process technology and advanced power, gating, and clocking technologies to deliver a cool-and-quiet gaming experience compared with their last generation. Polaris boasts a brand new display engine and HDR-ready capabilities while the new Radeon WattMan (formerly AMD Overdrive) offers a new level of customization and control over clocks, voltages, and temperature. And as with previous generations, Radeon software tends to optimize the hardware as drivers mature, improving gaming performance over time.
Power tends to become the limiting factor for performance. High-end graphics products such as the Radeon R9 300 Series are limited by power delivery to 300W, while notebook graphics must use as little power as possible to deliver excellent battery life and low heat.
The GCN architecture is AMD’s foundation for performance across their entire graphics ecosystem, from integrated notebook solutions to high-end discrete graphics cards for VR and PC gaming.
For the last five years, graphics processors have relied on the 28nm node. However, for Polaris, AMD has selected Samsung and Global Foundries’ 14nm FinFET-based process technology which can reduce power consumption and enable operating voltages that are significantly lower than the previous generation, thereby cutting active power by nearly one-third. Instead of requiring 2 PCIe connectors, the RX 480 that we tested gets by with only 1, yet still it is supposed to deliver R9 390 performance.
New Features for Polaris
To accompany the new Polaris architecture, Radeon WattMan is AMD’s new overclocking utility that controls GPU voltage, engine clocks, memory clocks, fan speed and temperature. WattMan is based on OverDrive features but offers new ways of more precise overclocking controls. With the new control over voltage and per state frequency curve for GPU clocks, more comprehensive tuning control is now available. GPU core and memory clocks can be adjusted per available DPM state for greater control. Along with voltage control per state. Voltages are not shared between GPU and memory clocks, but are set independently.
WattMan also features advanced fan and temperature control. Temperature maximum and target can now be set. Along with Power limit, the new control allows even further customization. Max temperature is the absolute high temperature before the system clocks are reduced to cool down the GPU. Target is the temperature before the fan speed is raised to cool down the GPU. Power limit boosts or reduces the power sent to the GPU. This can be increased or reduced by plus or minus 50% in Polaris 10 XT. WattMan even features data capture and a historical view of GPU activity, temperature, fan, and clock speeds.
With this new control, fan minimum speed, target speed, and minimum acoustic limit can now be set. Minimum, is the absolute minimum the fan can run at. Target, is target maximum fan speed, the fan will run at if temperature level is not above target. Minimum Acoustic Limit is the clock limit/threshold for acoustics.
Async Shaders is a feature that allows complex graphics tasks to use all available AMD Radeon graphics resources simultaneously. Breaking one big job into many small segments allows the work to be done more quickly, yielding greater performance. AMD’s Graphics Core Next architecture has dedicated hardware, called Asynchronous Compute Engines (ACE), which are specifically designed to do this job at high speed.
The Polaris architecture enhances the command processor with a new quality-of-service technique known as Quick Response Queue. It enables developers to designate a compute task queue as high-priority through APIs. Both high-priority and regular priority tasks co-exist and share the GPU’s execution resources, but the ACEs dispatch workgroups from the high-priority task ahead of normal tasks. This prioritization ensures that high-priority tasks will use more resources and complete first, without the command processor context switching out other lower-priority tasks. This technique is used extensively in AMD’s LiquidVR SDK to prioritize ‘time warping’, which is a latency and jitter sensitive task, and to ensure that the time warping occurs immediately before the vertical sync.
There are a lot of new features and exciting potential coming with Polaris and we want to see how some of these are practically implemented into RX 480 for gamers as we attempt to overclock it.
Let’s take a brief look at the specifications of the AMD Radeon RX 480 8GB.
The RX 480 4GB/8GB
With the RX 480, AMD wants to bring R9 390/GTX 970 performance into a much less expensive and less power-hungry card for gamers and for entry level VR. Much is made of Liquid VR for immersive Virtual Reality headsets which are already available this year. And FreeSync, DX12, Eyefinity, CrossFire and TrueAudio are featured for the Polaris RX 480 along with WattMan, AMD’s new overclocking utility.
The above specifications are for the 8GB $239 version of RX 480 that we are reviewing here which uses 8GB of 8Gbps GDDR5 memory. The $199 version of RX 480 it uses 4GB of 7Gbps memory, and we have not tested it.
The specifications of the RX 480 are quite impressive for a $199 to $239 card, especially compared to the more expensive R9 290X/390 which use a lot more power to achieve similar performance.
Our Testbed of Competing Cards
Here is our testbed of 5 competing cards and we shall test 26 games and 1 synthetic benchmark using Core i7-4790K turbo locked to 4.4GHz by the BIOS, ASUS Z97+ motherboard and 16GB of Kingston “Beast” 2133MHz HyperX DDR3:
- RX 480 8GB – $239 (AMD’s new Polaris architecture card)
- GTX 980 4GB
- GTX 970 EXOC by GALAX, 4GB
- R9 390 OC by XFX 8GB
- R9 290X 4GB – reference non-throttling 1000MHz Uber mode
These are the 5 cards that we are testing to see where the RX 480 stands. We are using 26 modern games and 1 synthetic benchmark at 1920×1080, 2560×1440, and at 3480×2160 resolutions.
How does the RX 480 8GB compare with other VR-ready cards?
This is the big question: How does the RX 480 compare with other cards in a similar performance range?
First, let’s take a closer look at the new Radeon RX 480.