In an interview with IGN, lead system architect Mark Cerny revealed the additional RAM is DRAM, which is slower than the GDDR5 in the system, but will still provide a performance benefit.
“We felt games needed a little more memory, about 10 percent more, so we added about 1GB of slow, conventional DRAM to the console,” he said.
Cerny went on to explain that the 1GB of DRAM would be used to store background applications when switching to a game, instead of allocating space on the GDDR5 RAM for it. Essentially, this gives the PS4 Pro more of the faster RAM to use on games.
The PS4 Pro launches on November 10, priced at $400. It features a 1TB hard drive but does not have a 4K Blu-ray player in part because Sony says it sees a shift towards streaming.
Sony has also confirmed you will be able to swap out the internal hard drive for the PlayStation 4 Pro, as is also the case for the standard PS4 and the PS3. PS4 Pro owners will be able to manually swap the hard drive and scale up to 6 Gb/s. This is double the speed of the original PS4’s SATA II interface, which scales up to 3 Gb/s.
For lots more on the PS4 Pro’s specs, price, and features check out our in-depth breakdown.