>>507081601PS3 used XDR memory which was a competitor to DDR at that time.
It was very good in terms of latency but not so good in bandwidth, for the time
The PS3's memory architecture was a bit strange for a console in that it had 512MB of total memory divided into 256MB main RAM and VRAM, but the CPU and GPU can both do DMA with each, leaving it to devs to work out which was faster in production.
The Xbox 360 was basically the PS3 with unified memory, DDR2 instead of XDR and a much less complicated CPU arch.
The PS3 could in theory get much better CPU performance than the 360, but it didn't normally work that way in practice.