How is Sony going to implement 8GBs GDDR5 in PS4? *spawn
- Thread starter Sonic
- Start date
I wonder how they are going to do the 8GB gddr5 (by the numbers, 256bit @ 1375Mhz).
It would require 16 4gbit gddr5 chips in clamshell mode (so later revision could use 8 8gbit chips for smaller footprint/cost savings) but the problem is not even 4gbit gddr5 chips exist yet as far as I'm aware (and using 2gbit chips would not only require a huge amount of chips but it's impossible on a 256bit bus). I guess they got a deal with someone securing all wavers of the not-yet-existing chips
.It doesn't look like a short-term solution to me, for the stacking you'd look at a new chip, so maybe with a future die shrink.
It's pretty hard to get info on GDDR5 bulk prices. Looking at the price differential between 7770 1/2GB, 7850 1/2GB and 660 2/3GB, we can try to infer the extra gigabyte is about the same price as 4-5 GB DDR3 (all retail prices)
4GB of DDR3 is $20 (spot price), implying $80-$100 for 4GB DDR5.
Durango's memory system offers the same aggregate bandwidth (104GB/s + 68 GB/s) as Orbis (170GB/s) for a fraction of the price.
Cheers
CrossPosted from: http://forum.beyond3d.com/showpost.php?p=1710535&postcount=622
Granted that chart shows old prices, but surely the price wouldn't have dropped by 50%, would it? And also the double density would raise cost too.
The AMD 6970 has 176 GB/s memory bandwidth using 1375MHz Memory Clock (5.5 Gbps GDDR5)
4 * $48.57 (2GB 6970) = $194.28
8 * $18.45 (1GB 6670/6850/6870) = $147.60
4 * $36.90 (2GB 6950) = $147.60
The AMD 6950 has 160 Gb/s 1250MHz Memory Clock (5.0 Gbps GDDR5)
The AMD 6870 has 134.4 Gb/s 1050MHz Memory Clock (GDDR5)
The AMD 6850 has 128 Gb/s 1000 MHz Memory Clock (GDDR5)
Granted that chart shows old prices, but surely the price wouldn't have dropped by 50%, would it? And also the double density would raise cost too.
The AMD 6970 has 176 GB/s memory bandwidth using 1375MHz Memory Clock (5.5 Gbps GDDR5)
4 * $48.57 (2GB 6970) = $194.28
8 * $18.45 (1GB 6670/6850/6870) = $147.60
4 * $36.90 (2GB 6950) = $147.60
The AMD 6950 has 160 Gb/s 1250MHz Memory Clock (5.0 Gbps GDDR5)
The AMD 6870 has 134.4 Gb/s 1050MHz Memory Clock (GDDR5)
The AMD 6850 has 128 Gb/s 1000 MHz Memory Clock (GDDR5)
I am thinking they might want to reserved like around 1GB now that they have 8 to work with.
These prices can't possibly account for the new 4gb chips which will certainly be used in Orbis. Those prices are for at least 32 chips.
Initial pricing on higher density chips probably isn't lower. It might be by the end of the year.
IIRC latency of gddr5 should be quite comparable to ddr3 (I've never seen hard numbers). Yes there's some more overhead associated but in the end it isn't really all that significant, assuming a decent MC.
We could compare the retail price of the HIS Radeon HD 7850 4GB iPower IceQ Turbo to the HIS Radeon HD 7850 2GB iPower IceQ Turbo and then double it, to provide a baseline.
In reality, the difference should be smaller than this since Sony will be producing the PS4 in much greater quantities than HIS does of the 7850 4GB.
The 2GB version is currently US$200 on Newegg, while the 4GB version is US$280 on Newegg (the only store where it is currently sold), but the latter figure should come down as retail availability expands.
Guru3d states an expected retail price for the 4GB version of around US$225. http://www.guru3d.com/articles_pages/his_radeon_7850_ipower_iceq_4gb_review,25.html
Admittedly this is for 153.6GBps GDDR5 rather than 176GBps GDDR5, but I doubt it would make much difference to pricing.
In reality, the difference should be smaller than this since Sony will be producing the PS4 in much greater quantities than HIS does of the 7850 4GB.
The 2GB version is currently US$200 on Newegg, while the 4GB version is US$280 on Newegg (the only store where it is currently sold), but the latter figure should come down as retail availability expands.
Guru3d states an expected retail price for the 4GB version of around US$225. http://www.guru3d.com/articles_pages/his_radeon_7850_ipower_iceq_4gb_review,25.html
Admittedly this is for 153.6GBps GDDR5 rather than 176GBps GDDR5, but I doubt it would make much difference to pricing.
We've had knowledgable folk tell us 8 gigabit GDDR5 chips aren't available so Sony would need to double the bus width or clamshell the RAM or something decidedly non-trivial. the 8 GBs GDDR5 was the real surprise and eye-opener. After that I should have switched off instead of sitting through an hour of old PR videos...
We've had knowledgable folk tell us 8 gigabit GDDR5 chips aren't available so Sony would need to double the bus width or clamshell the RAM or something decidedly non-trivial. the 8 GBs GDDR5 was the real surprise and eye-opener. After that I should have switched off instead of sitting through an hour of old PR videos...
Heck, are 4gbit GDDR5 chips even available?
Samsung and Hynix largest chips are both 2gbit chips with x32 interface.
If Sony needs to use custom packages, it's added cost to a pile of added cost.
Cheers
(((interference)))
Veteran
We've had knowledgable folk tell us 8 gigabit GDDR5 chips aren't available so Sony would need to double the bus width or clamshell the RAM or something decidedly non-trivial. the 8 GBs GDDR5 was the real surprise and eye-opener. After that I should have switched off instead of sitting through an hour of old PR videos...
Perhaps the bus was always 256 bit? The rumours recently had a reduction in bw from 192 to 176 GB/s so perhaps that can give us another clue.
Betanumerical
Veteran
Its in the official Sony docs as 8GB GDDR5 * 176GB/s. so its pretty certain its that.
But that was before we knew about background recording and upload of gameplay footage etc. That sh*t dont come for free and that certainly doesnt leave alot for the O/S if its only 512MB.
Obviously not basing that on anything other than assumption. But seems a no brainer that the kind of live social/online infastructure Sony is building around the OS is going to require some memory