| drkohler said: I don't think we will see stacked ram in a future PS4. Not worth the effort. What you win in surface you loose in height, essentially. By the time this becomes an option, we are looking at a potential PS5. Potential savings are in the SoC (which might be a multi-die assembly for the first year(s). This 28nm stuff is brand new (at least for GF, a potential manufacturer), untested technology so the yields are probably very low on the cpu and gpu dies. If you have a single large die and the cpu part is bad, you have to throw away the gpu part as well and vice-versa. If you have two separate dies, you only have to throw away the defective die, not both dies). If you look at any PC dimm that has a heat spreader, you'll notice that the heat spreader is not in contact with the ram chips, but with the small pcb board the ram chips are soldered onto. Ram chips are basically cooled through their pins, the heat flows through the pins onto the pcb and barely through convection. So if you have stacked ram, you just insure the pins are "large enough" (whatever that means in the end) soldered onto a "large" heat spreader. Better airflow around the heat spreader will do the job (if I look at my board with four ddr3-1600 dimms, the air flow is pretty shitty but the heat spreaders apparently still do the job). |
When you say not worth the effort you mean basically just the space the ram takes away ?
But GDDR5 produces more heat and eats up alot more power than DDR3 or DDR4. If this could be reduced by lets say 20 Watts through stacked ram the powersupply could be made smaller and cheaper aswell as the cooling and the board. the number of chips might be less too DDR3/4 densities are easier to increase than GDDR5.
Ofcourse if its not worth the effort Sony won't do it. But we don't know if it might be worth the effort someday in the future.
Sure guaranteed savings are in the SoC, but stacking could come out cheaper than using GDDR5 one day. If the process is proven and widespread. PS2 got redesigned after PS3 was on the market so who knows.
