I believe that one of the biggest challenges of PS4/X1 is the efficient use of the 8 cores on their CPU.
The single thread performance of Jaguar cores are not that good (which is expected since one of its targets are Tablets and Netbooks). It also does not have something like Intel's Turbo Bust to improve its single thread performance by a dynamic/on-demand overclock. To offset these limitations, developers have the option to parallelize their CPU intensive code.
Unfortunately to create such a code developers have to face some interesting problems:
1) Not every task can be parallelized;
2) Some task can be parallelized but the result is a code that runs slower than the original code;
3) Once parallelized a code becomes non-deterministic which may lead to a lot of trouble to test it;
4) Data synchronization (starvation, racing conditions, deadlock, etc.);
5) Using 100% of 8 cores at the same time is almost impossible unless you are coding a solution to something homogeneous like weather forecast;
By the way, I read that since their CPU is essentially two independent Jaguar combined hence the CPU may not be suited to allow a process to have access to the 8 cores at the same time (four cores for each process), can someone please confirm this to me?
