That is not how it works. At the beginning of the development, you start with a blank sheet of paper and make two decisions on cpu, gpu and ram layout. First, you either go unified memory (XBox 360) or separate memory (PS3, PC). Each solution has its (dis-)advantages which have been discussed to death. Both companies went unified memory. The second decision is how to hook the gpu to the memory. The simple way is use graphics memory (expensive and fast). If you go the cheap route (ddr), you need something to offset its slow speed, which is local gpu memory (cache structured or bank addressable). Both solutions lead to the same performance if carried out correctly.

When the development started, MS already had the "entertainment angle" in sight, so they neeed a 8G ram console for all the stuff. Sony pondered on 2G or 4G ram for a games console. (At that time, 1G gddr5 PC graphic cards were "cool", 2G cards "insane", 4G cards unaffordable). MS went eSram instead of eDram (like WiiU) because of ? (? could be speed/ power/ process technology not available at 28nm/  related). Probably an 80mm^2 transistor grave or half the gpu die size...

The rest is history. 4GBit gddr5 chips became available in quantities and Sony got a last-minute deal (or it was planned intention since the clam-shell layout allowed for simple chip replacement without adding anx design costs/changes) and went up to 8G, apparently. Major piss-off for MS. Now we have Sony: $150 APU + $90 gddr5 versus MS: $220 APU + $15 ddr3 (These numbers are not made up and prices will of course go down over time but just not this year in the initial fab runs).

don't take this personally, but you said things i already know... in the end you agree with me (eSRAM its what makes the MS chip more expensive and they use eSRAM because they choose DDR3 memory type, witch is cheaper than GDDR5) after this you post similar numbers as mine but true numbers that say the same... cool man... :D
i was just trying to point something out to Slimebeast that i think he was missing in his argument with walsufnir...

BTW eSRAM instead of eDRAM is because SRAM is true cache ram and is faster, but more expensive and has more transistors (bigger in size, obviously)...

I wasn't answering to your posts, I was just explaining that both solutions can be equivalent in performance, there is no "how stupid of MS to use ddr3" argument. (And as a sidenote, cache ram is quickly moving away from sram to edram)

$220 for APU?
$150 for APU?
$90 for memory

I can say to you guys these numbers are far away from the real manufacture costs... the most expensive AMD APU is priced at $120 to retail (not manufacture cost) a 246 mm² die made in 32nm SOI process.

28nm is cheaper than 32nm... there are no way PS4 APU (that will have close to the same size of the most expensive AMD APU) will cost $150 to manufacture.

Both APUs with a 80% GOOD chips per wafer will cost less than $100 to manufacture.

If they aren't made up where did you get the numbers from?

They are made up...

A APU to have these costs in 28nm needs less than 20% of good chip per wafer... a ~300mm² APU.

I wil never talk about sources, ever. I am losing patience, however, reading all the nonsense in this and other forums, so I might simply refrain from reading and posting one day.

Even without sources, you could get a good idea about chip manufacturing and "how it works generally" by reading specific semiconductor forums where the "semiconductor people exchange ideas". These are not the easy-to-read forums, there are scientists, not gamers, contributing.

And ethomaz: If it makes you happy: Yes, I have no clue and make up all my numbers, everytime - After all, I am not a scientist with 20+ years insight into various mass manufacturing technologies ,I just made up that part, too. Happy now?

I knew it.

DDR3 is rising in price anyway.
Will probably increase massively in price once the PC transitions over to DDR4, that's going to erode on any potential cost savings Microsoft made by opting for DDR3 to begin with if it happens, GDDR5 memory will be here and getting cheaper for a long time yet, low-end cards are yet to use it exclusively, so still more economies of scale to be taken advantage of there.

you did quote me... and if some one use that argument, you should quote them... i certainly didn't.

@bold, so you are saying that MS did wrong? SRAM is much better and a true cache RAM with lots of advantages over DRAM, only disadvantages is size, power consumption and cost... MS did good here (performance wise). and if that is happening (moving from SRAM -> DRAM) it has to be because of price and companies wanting to be "green". if they are indeed having problems with the eSRAM chip, the move to a eDRAM chip would cause a performance hit in the overall system but produce less heat... choices... choices...