AMD Radeon RX 480 4GB versus Radeon RX 480 8GB

By Nathan Kirsch

4GB versus 8GB of Memory on the Radeon RX 480

Yesterday we took an in-depth look at the new AMD Radeon RX 480 8GB reference card and found that it was a great card for gamers running 1920 x 1080 or 2560 x 1440 displays. The performance was pretty good for a $239 graphics card, but most gamers know that 8GB of GDDR5 memory is overkill if you are just going to be doing 1080P gaming. We had a number of people ask us about how the 4GB card performs since it costs less and $199 is more appealing to them. Let’s find out together! AMD Radeon RX 480 Bottom

All of the AMD Radeon RX 480 at-launch graphics cards have shipped with 8GB of memory on them. That means if you run out and buy a 4GB card this very second it really does have 8GB of memory on the card. AMD disabled it through a special vBIOS and also lowered the clock speed of the memory on the 4GB cards.

  • AMD Radeon RX 480 8GB Reference Card – Runs at 8Gbps, but board partners can use other speeds on custom cards as long as it is above 7Gbps
  • AMD Radeon RX 480 4GB Reference Card – Runs at 7Gbps, but board partners can use other speeds on custom cards as long as it is above 7Gbps
Radeon RX 480 ellesmere XT BIOS Flash
Flashing the Radeon RX 480 At-Launch Card To Change The Memory Capacity & Speed

We got out hands on on both vBIOS revisions and have taken the AMD Radeon RX 480 reference card and have tested with both the 4GB and 8GB versions of the vBIOS!

AMD ellesmere XT vBIOS Flash

The update process was a simple executable that was run on the desktop that took a few minutes to run and after that we could lock the memory to run at 4GB or run all 8GB.

For this article we ditched the press driver (Crimson 16.6.2 beta) and installed the public driver (Crimson 16.6.2 WHQL). We also tested at three different configurations to give you the best possible results as board partners will be using both 7Gbps memory and 8Gbps memory on their custom RX 480 cards next month.

  • AMD Radeon RX 480 8GB – Running at 8Gbps for 256 GB/s of memory bandwidth
  • AMD Radeon RX 480 4GB – Running at 8Gbps (Overclocked by 250MHz using AMD WattMan)
  • AMD Radeon RX 480 4GB – Running at 7Gbps for 224 GB/s of memory bandwidth

full-memory

With the AMD Radeon RX 480 reference card running the 4GB vBIOS we found that the memory topped out at 3940MHz when running game titles at a 4K resolution. Before the flash the same game titles were using nearly 6.5GB, so it looks like the memory is being capped.

Let’s run these three Radeon RX 480 card configurations and see how performance looks on a few benchmarks.