SBMfromLA :
Here is part of an article I found concerning those types of Adapters:
Pros and Cons
The benefit of using a DVI to VGA adapter is that you won’t have to buy a new monitor in order to use your new video card, but there is a trade-off. Because you are using the adapter, you are downgrading the DVI signal to make it work via VGA. This means you aren’t getting the best quality output from your new video card, which kind of defeats the purpose of upgrading in the first place.
In most cases, the quality degradation going from digital to VGA is not perceivable unless the display has trouble accurately recovering the pixel clock and aligning all three channels. The main reason people upgrade GPUs is to game either at higher resolution or higher frame rate, and unless you want to game at resolutions beyond 2048x1536, VGA is capable of handling the usual 1920x1080/1200p60 as well.
BTW, the Asus R9-280X (at least the model I have looked at) has 1xDVI-I + 1xDVI-D ports, so one of the two ports should support DVI-to-VGA using a simple passive adapter to patch the GPU's analog channels through to the VGA pins. OP could also use a DVI-to-HDMI adapter instead.