It is as you say and that is the advantage of having unified memory. The PS3 like a PC was limited to only using 256MB of ram for system memory i.e the kind of stuff you see in your task manager on PC. It also had 256MB for video memory but that's just GPU memory, it can't be used as system memory under normal circumstances. This means the 360 gave devs great flexibility over how much ram their games could use with 360 games in general having a significant advantage in total ram available to games than the the PS3, in practice PS3 games were ram starved compared to 360 games and any task that relied on memory capacity was crippled on the PS3.If this were the case then why did you state the 360 as having 512MB of RAM considering some (most) of it would undoubtedly be used as VRAM. As far as I know the VRAM could be used as system RAM too with some hacks but at a drastically reduced bandwidth and higher latency.