Blender doesn't require a powerful hardware setup for anyone who just wants to start using it. Is there anything special about the hardware needed for architectural visualization? Well, if you want to produce photorealistic renderings, then I strongly recommend you to upgrade your system with more RAM and CPU power, because these kinds of rendering require a lot of processing. But if you want to create renderings that look more like a sketch or anything that doesn't look photorealistic, it won't be necessary to use a powerful computer, because this kind of rendering demands less resources.
The Blender Foundation recommends these minimum requirements: