My Sticker says ATI X1600 256, but in Catalyst Control info says 512mb....which is it?

Most specs say the Z96j comes with the ATI X1600 with 256mb, even my sticker says that, but when I check system info in Catalyst Control Center, it says 512mb. What do I have?

 

You have 256MB of dedicated video RAM and 256MB of shared system RAM. It's actually called Hypermemory intended into tricking the average person into thinking more video memory means better graphics card. An Nvidia equivalent of the Hypermomeory scheme would be Tourbocache which is pretty much the same thing. It wouldn’t even matter if you had 512MB of dedicated VRAM anyhow since the X1600’s 128-bit memory bus wouldn’t recognized much more than 256MB of VRAM anyhow. Not suggesting there's anything wrong with your Mobilty X1600, cause the same would apply to the present day HD 3650 512MB/1024GB with its 128-bit memory bus.

 

Ok thanks for clearing that up for me.

But now I'm confused about the memory bus(actually buses in general I'm not sure about where in the flow of processing they sit, and what they do). When you say 128bit not recognizing more than 256 VRAM, that is on top of the 256 built in RAM? How does the bit of the bus effect the memory, in terms of how much is needed to use how much memory?

Thanks again

 

By all means I'm no expert in hardware to go that in-depth, but rather I've found this to be so from the available information around. All you have to know is:

64-bit:128MB, 128-bit:256MB, 256-bit:512MB, etc