Ubisoft Reflections rounded off day two of last week's Develop conference with an intriguing talk, tantalisingly entitled "Tips and Tricks for Porting to Next-Gen". For Digital Foundry, it was a must-see presentation primarily because the vast majority - and perhaps even all - of the multi-platform games we'll be playing on Xbox One and PlayStation 4 by the end of the year have been derived from PC code, necessitating some level of porting across to the new hardware.
More crucial is how the 8GB of RAM in the PlayStation 4 is utilised. This unified pool is a significant advantage over platforms like PC and PS3, where CPU and graphics RAM takes the form of two entirely separate pools of memory. The PS4 operates a system where memory is allocated either to the CPU or GPU, using two separate memory buses.
"One's called the Onion, one's called the Garlic bus. Onion is mapped through the CPU caches... This allows the CPU to have good access to memory," explains Jenner.
"Garlic bypasses the CPU caches and has very high bandwidth suitable for graphics programming, which goes straight to the GPU. It's important to think about how you're allocating your memory based on what you're going to put in there."
Lots of interesting tid-bits and insights into a developers creation process for PS4 in a relatively lengthy article. Please read the source