PS4 has extra low power processor and 256MB DDR3 RAM

#1
Seemed like the news was too important to be buried in the iFixit thread.

On mobile so I can't link right now, but it's a 2Gb Samsung chip attached to the low power secondary processor.

My guess is that it is used for caching the 15min video recording.
 
#9
I was wondering what's stopping Xbox from matching Sony's 15min video recording, given that their Upload Studio feature is very annoying to use if you have to manually mix 5 minute recordings.

Guess this makes sense.
It doens't, you could still use the HDD to store the video, the RAM is just for buffering.
 
#34
We already knew there was an extra processor, right?
Well there was a debate as to whether there would be a separate processor or if it was all on the main processor. It remains to be seen what is in the secondary processor but it makes sense to have a video encoder and audio encoder as neither has a cost of more than $1 each and a dual ARM A7 will be a few dollars.
 

ElTorro

I wanted to dominate the living room. Then I took an ESRAM in the knee.
#35
Probably all just for background processing. I am rather skeptical that this memory is used as a backbuffer for gameplay recordings. The APU would have to have access to that memory for that to work, so buffering the video in its own memory seems more straight forward.

Or the chip is actually hanging between the APU and the HDMI-Out and can handle video capture completely on its own.
 
#36
Well there was a debate as to whether there would be a separate processor or if it was all on the main processor. It remains to be seen what is in the secondary processor but it makes sense to have a video encoder and audio encoder as neither has a cost of more than $1 each and a dual ARM A7 will be a few dollars.
Video encoders are built into the AMD APU these days.
 
#37
The background processor is obviously for what we've been told it's for since the beginning, managing network and I/O functions while the system is in its low power stand-by state. Audio, Video Encoding and all that stuff happens in the APU. There's no good reason for it to be elsewhere.
 
#38
Probably all just for background processing. I am rather skeptical that this memory is used as a backbuffer for gameplay recordings. The APU would have to have access to that memory for that to work, so buffering the video in its own memory seems more straight forward.

Or the chip is actually hanging between the APU and the HDMI-Out and can handle video capture completely on its own.
Someone theorized on B3D it was for security functions but then also mentioned 256 is a lot for security.
 
#40
ram is probably just working space for downloads and connecting to the PSN etc. I wonder if it has its own little embedded OS? Guess it must have.

does it only do background downloads when in standby (annoying pulsing orange LED), or also when you're powered down?
 
#41
Seemed like the news was too important to be buried in the iFixit thread.

On mobile so I can't link right now, but it's a 2Gb Samsung chip attached to the low power secondary processor.

My guess is that it is used for caching the 15min video recording.
No. GameDVR videos are encoded with 720p30 with ~5mbit quality. That's around ~500MB of data.

My guess is that background processor uses that ram for its own needs, mini OS, drivers for southbridge, app for connecting to PSN, cache for installing stuff, etc.
 
#42
No. GameDVR videos are encoded with 720p30 with ~5mbit quality. That's around ~500MB of data.

My guess is that background processor uses that ram for its own needs, mini OS, drivers for southbridge, app for connecting to PSN, cache for installing stuff, etc.
yeah. Its kind of a nuts amount though - same ram as PS3 (not including the VRAM) just for a background processor.
 
#44
Been stated repeatedly that it's there for low/standby power functionality
But we didn't know about the RAM. People speculated that it would have to power the whole 8 GB of GDDR5 while in standby.

Though that probably still will be the case with the suspend feature when it becomes available, so I'm not sure what the extra RAM is for.
 
#45
Though that probably still will be the case with the suspend feature when it becomes available, so I'm not sure what the extra RAM is for.
Keeping APU and 8GB of GDDR5 in standby state [self-refresh mode] will use very low power [~0.5 W]. All the computation power is stopped, all cpu/gpu/ram clocks are down to zero, hardware receives just enough power to retains its "zeroes and ones" alive.
 
#46
Well there was a debate as to whether there would be a separate processor or if it was all on the main processor. It remains to be seen what is in the secondary processor but it makes sense to have a video encoder and audio encoder as neither has a cost of more than $1 each and a dual ARM A7 will be a few dollars.
Do we know how many CPU cores the ARM chip has?
 
#47
ram is probably just working space for downloads and connecting to the PSN etc. I wonder if it has its own little embedded OS? Guess it must have.
Yeah, it must. The complications of having to pass control of the system back and forth between the background processor's OS and the main OS are probably why we don't have game suspension at launch.

yeah. Its kind of a nuts amount though - same ram as PS3 (not including the VRAM) just for a background processor.
Well, there's a few ways to think about it. It's enough that they can buffer downloads and only spin up the drive occasionally to burst write the data, keeping noise and power use as low as possible. And they have to think about what the price and availability of this kind and capacity of RAM will be for the life of the product. With both the PS1 and PS2 they discontinued manufacturing when it got to the point that the parts they needed were so obsolete the prices they'd have to pay to get them made became prohibitive. a 64MB DDR3 chip might have been adequate for their needs today, and cheap, too, but what happens in 5 years when no one mass produces DDR3 in that density anymore?