PlayStation 4 (codename Orbis) technical hardware investigation (news and rumours)

[Exophase]

Cerny: The second custom chip is essentially the Southbridge. However, this also has an embedded CPU. This will always be powered, and even when the PS4 is powered off, it is monitoring all IO systems. The embedded CPU and Southbridge manages download processes and all HDD access. Of course, even with the power off.

Where do you read "custom ARM chip"? It's a reasonable expectation for some embedded CPU to be ARM but there's no guarantee.

Sony says they'll include a big HDD with every console. I doubt they'll also include 16GB of flash. Vita has no spinning disc so it needs something.

AMD didn't license TrustZone. They licensed a Cortex-A5 which includes TrustZone (and other hardware parts like ARM's bus). There's a difference. We don't really know why they wanted it and we don't really know what makes sense for PS4 and what Sony will want to use.

 

[MrFox]

I don't know about the 16GB flash rumor, but it's a big plus to have the OS in flash:

• The entire firmware becomes very responsive, quick booting. An OS with a low memory footprint is hard on random-io, takes big advantage of flash.
• The PS4 should have a resilient dual OS partition (Cerny said it would do background firmware install, this is probably the best way), so usable capacity would be half.
• Prevents the OS from trashing the HDD when popping a browser or other apps, gives the running game a guaranteed I/O performance despite the multitasking.
• It allows downloads while in standby without spinning up the HDD, easier to comply with EU requirements. Just spin up the disk and flush every few GB.
• It brings back the ease of replacing the HDD without having to re-download the entire firmware (the fat PS3 did that, they dropped the feature with the slim).

 

[Grall]

Single flash devices as used in consumer electronics are rarely particularly fast, and quite often in fact monstrously slow. You can bet that it's because of its onboard flash that switching to/from apps on the Wuu is so slow as it is right now.

 

[patsu]

Where do you read "custom ARM chip"? It's a reasonable expectation for some embedded CPU to be ARM but there's no guarantee.

Sony says they'll include a big HDD with every console. I doubt they'll also include 16GB of flash. Vita has no spinning disc so it needs something.

AMD didn't license TrustZone. They licensed a Cortex-A5 which includes TrustZone (and other hardware parts like ARM's bus). There's a difference. We don't really know why they wanted it and we don't really know what makes sense for PS4 and what Sony will want to use.

In their PS4 article, Eurogamer mentioned that the custom processor is ARM-based.

16GB Flash rumor may have started from keeping OS firmware, built-in apps, and app-switching. I think I read about it before the secondary custom chip announcement (DF reported the custom chip as an additional independent compute unit at that time). So far, people were skeptical about 2GB, 4GB and 8GB GDDR5 and it happened. OTOH, early rumors about 14+4 config didn't really materialize. We will have to wait for more details.

ARM did more than just licensing an ARM-A5 chip. In their press release, they will incorporate TrustZone IP into their APUs. There is also broad-level partnership in this area. May not be surprising if AMD wants a foot into ARM opportunities.

EDIT: Naturally, it is also possible for Sony to roll their own solutions. Or perhaps like their GPU approach, they customize existing IP for their use.

 

[MrFox]

Single flash devices as used in consumer electronics are rarely particularly fast, and quite often in fact monstrously slow. You can bet that it's because of its onboard flash that switching to/from apps on the Wuu is so slow as it is right now.

What I can bet, is that Nintendo took the lowest possible eMMC (samsung KLM8G2FE3B) connected in 4bits mode (just so it's even slower). It's the kind of chip they put in the cheapest smartphones and ebook readers, and the $49 android tablets. They do 10MB/s and 400 iops. Samsung has a great range of products up to a class2000 eMMC chip that clocks 260MB/s and 5000 iops. There's also plenty of reasons why Nintendo couldn't achieve a responsive OS, they just don't know how to write an elaborate OS. But I digress.

Taking the question in reverse, if Cerny decided to have the OS in flash specifically for i/o speed instead of capacity, he would use the high-speed parts. Samsung has a nice 16GB eMMC in production that's 140MB/s and 3500 iops (KLMAG2GE2A).

 

[Silent_Buddha]

What I can bet, is that Nintendo took the lowest possible eMMC (samsung KLM8G2FE3B) connected in 4bits mode (just so it's even slower). It's the kind of chip they put in the cheapest smartphones and ebook readers, and the $49 android tablets. They do 10MB/s and 400 iops. Samsung has a great range of products up to a class2000 eMMC chip that clocks 260MB/s and 5000 iops. There's also plenty of reasons why Nintendo couldn't achieve a responsive OS, they just don't know how to write an elaborate OS. But I digress.

Taking the question in reverse, if Cerny decided to have the OS in flash specifically for i/o speed instead of capacity, he would use the high-speed parts. Samsung has a nice 16GB eMMC in production that's 140MB/s and 3500 iops (KLMAG2GE2A).

To get good performance out of flash memory you need a good flash memory controller (not cheap) and multiple fast flash chips (so low capacity is out) in order to interleave read/writes. It's a fairly expensive proposition. It's why you don't see cheap fast USB keys. And why you pretty much never see fast, low capacity USB keys. I don't think there's any really fast USB keys under 32 GB due to the requirements to get good performance. The same applies to SSDs only more so as they can generally afford the more expensive flash memory controllers that aren't practical in a USB key as well as the DDR based caches.

They do still have good random read access which helps to overcome the generally low sequential transfer speeds of small amounts of flash memory. At which point it becomes a bit of a wash and you're better off just using the included high capacity HDD with high density platters as cost savings is then multiple orders of magnitude.

Then again, if Sony is hellbent on losing massive amounts of money with every PS4 sale, then flash memory for storage makes lots of sense.

Regards,
SB

 

[Grall]

Taking the question in reverse, if Cerny decided to have the OS in flash specifically for i/o speed instead of capacity, he would use the high-speed parts. Samsung has a nice 16GB eMMC in production that's 140MB/s and 3500 iops (KLMAG2GE2A).

There's no reason to believe sony would reason any different than nintendo here. They sure as hell didn't with the PS3; updating its firmware takes fecking forever. Nobody would cheer them for paying extra for the super fast class of flash devices except the fanboys, who mindlessly cheer them on regardless of everything anyway.

 

[MrFox]

To get good performance out of flash memory you need a good flash memory controller (not cheap) and multiple fast flash chips (so low capacity is out) in order to interleave read/writes. It's a fairly expensive proposition.

Not for an embedded system like this. I provided the part number and the specs. Please look it up and start your argumentation from there. With BSD and it's plethora of modern open source file systems supporting raw flash, everything becomes easy. No need for an expensive controller. There's a CPU in the south bridge, it's more than enough for everything a modern flash file system would need, even including wear leveling.

About read/write interleave. Why would an OS partition need heavy write access? Remember there's a CPU in the south bridge and it's entire purpose is to manage the IO. The write cache would be right there with it. Tight interleaving of read/write is reserved for badly written OSes with file systems throwing fsync and write barriers left and right for no reason (actually there's a reason, but I won't go there). A game console OS won't have this problem. read/write ratio on the OS partition will also be almost only read, while writes can be buffered a lot.

I don't think there's any really fast USB keys under 32 GB due to the requirements to get good performance. The same applies to SSDs only more so as they can generally afford the more expensive flash memory controllers that aren't practical in a USB key as well as the DDR based caches.

I gave you an eMMC chip that's 16GB and does 140MB/s with 3500 read iops, no need for a controller. The chip package is 16mmx12mm, while the one in the WiiU is 11.5mmx13mm, the exact same line of chips from the same company. These chips target tablets and smartphones. It's eMMC. It's not SD, not sata SSD, and certainly not USB key. Please follow from this fact.

 

[Silent_Buddha]

About read/write interleave. Why would an OS partition need heavy write access? Remember there's a CPU in the south bridge and it's entire purpose is to manage the IO. The write cache would be right there with it. Tight interleaving of read/write is reserved for badly written OSes with file systems throwing fsync and write barriers left and right for no reason (actually there's a reason, but I won't go there). A game console OS won't have this problem. read/write ratio on the OS partition will also be almost only read, while writes can be buffered a lot.

I'm not talking about interleaving writes combined with reads. You have to interleave reads in order to get good read performance. The same goes for writes. Hence, the fewer NAND modules you have on the package the slower your read speed OR write speed. This is why 32 GB devices are slower than 64 GB devices which are slower than 128 GB devices etc. Once you get to 256 GB devices and up you have the same channels and performance levels out.

I gave you an eMMC chip that's 16GB and does 140MB/s with 3500 read iops, no need for a controller. The chip package is 16mmx12mm, while the one in the WiiU is 11.5mmx13mm, the exact same line of chips from the same company. These chips target tablets and smartphones. It's eMMC. It's not SD, not sata SSD, and certainly not USB key. Please follow from this fact.

I'll check into it, but so from a casual look, there's no information about pricing (so it's still quite likely to be expensive for a fast device at 16 GB) for the higher speed teirs. As well it does require a controller but it is on the package itself. In fact the one you listed appears to be their most expensive package. As well their own product information lists 1500 random IOPS, decent but not great. And that's for the expensive one.

The one that would most likely be featured in a console that isn't trying to bankrupt the company would likely be the KLMAG2WE4A (250 IOPS) or KLMAG2GE4A (400 IOPS) both of which would actually be slower than pretty much all modern day 5400 RPM HDDs. And they would STILL be more expensive.

So, no, you haven't given me anything to refute that it would be an expensive proposition with little upside. If this were a mobile device then yes, the cost premium would make sense. But for a console, when the storage ends up being orders of magnitude more expensive per GB while not offering a substantial increase in speed, then why increase the amount of losses you'll rack up with each console sale?

Regards,
SB

 

[Brad Grenz]

I think you're exaggerating the price of flash modules. Even the fastest SSDs are under a dollar a gigabyte now, and they have additional costs from the controller and packaging. In any case, just because Nintendo bought the cheapest, slowest flash they could find doesn't mean Sony would do the same, not if the intended application is performance sensitive.

 

[Grall]

Most of the OS - as in vast majority of it - will be stored on HDD, not flash, because HDD is magnitudes cheaper than even the cheapest, slowest flash on earth. So this whole discussion is entirely moot.

Flash will bootstrap the machine, likely hold enough data to rebuild system when you need to change the HDD, and not much more methinks. I have huge problems entertaining the idea of sony sticking a high-performance SSD-like storage system in PS4 just for the performance it brings. A console simply doesn't load enough stuff often enough for that to be worthwile or cost effective.

 

[Shifty Geezer]

I have a phone that has a full fledged OS, more versatile than PS4 needs to be, running in well under a GB. 1 GB Flash should be enough to install OS. Add 2 GBs for stability during installs, and that's loads. Apps can be stored on HDD. I dare say 1 GB flash would be enough for a core OS. Google suggests FreeBSD can fit in 300 MBs.

As the OS is write once, read many, read performance will be the most critical aspect. I'm thinking of PS3 Superslim 12GB here, with 4 GBs OS IIRC. Write speeds are diabolical, but the read speeds are okay and it's cheap. Shouldn't cost too much more to get a decent speed, just large enough, flash drive for the OS. As it would save HDD having to thrash for some OS functions (which could also just be loaded all into RAM now there's 8 GBs...), it makes quite a bit of sense to me.

 

[Silent_Buddha]

I think you're exaggerating the price of flash modules. Even the fastest SSDs are under a dollar a gigabyte now, and they have additional costs from the controller and packaging. In any case, just because Nintendo bought the cheapest, slowest flash they could find doesn't mean Sony would do the same, not if the intended application is performance sensitive.

Am I? A cheap SSD featuring slow speeds and old controllers can get down to around 0.70 USD per GB which is a whole lot cheaper than it was 2 years ago. That's for a 240-256 GB device, the sweet spot with regards to pricing. Drop down to low capacity SSDs and the price per GB goes up drastically to about 1.56 USD. Over double the cost per GB. And that's for a 32 GB device. Drop down to a 16 GB SSD and the price per GB would go up even more (likely into the 3.00 USD per GB range) if they were actually made.

Compare that to HDDs. The sweet spot is 3 TB 3.5" drives at about 0.045 USD per GB. 3.5" drives aren't likely to appear in a console however. So, looking at 2.5" drives the sweet spot for pricing is at the 1 TB level where it's about 0.08 USD per GB. And just as with flash drives as capacity goes down, price per GB goes up. A 500 GB 2.5" drive (as rumored for Durango) goes for about 0.12 USD per GB.

So, yes, I was exaggerating a bit with orders of magnitude. But it certain is more than an order of magnitude more expensive.

Now if you don't mind dropping the speed drastically by using a USB key flash controller or a cheap eMMC package you can lilely keep the price of 16 GB of storage to around 1.00 USD per GB or lower depending on how slow you want the device to be. And at that point you're going to likely be slower than a mechanical HDD anyway while paying more per GB.

I have a phone that has a full fledged OS, more versatile than PS4 needs to be, running in well under a GB. 1 GB Flash should be enough to install OS. Add 2 GBs for stability during installs, and that's loads. Apps can be stored on HDD. I dare say 1 GB flash would be enough for a core OS. Google suggests FreeBSD can fit in 300 MBs.

As the OS is write once, read many, read performance will be the most critical aspect. I'm thinking of PS3 Superslim 12GB here, with 4 GBs OS IIRC. Write speeds are diabolical, but the read speeds are okay and it's cheap. Shouldn't cost too much more to get a decent speed, just large enough, flash drive for the OS. As it would save HDD having to thrash for some OS functions (which could also just be loaded all into RAM now there's 8 GBs...), it makes quite a bit of sense to me.

At 1 GB the cost will be relatively small, but the speed will also be quite slow as well. In this case likely slower than the 5400 RPM drive. At which point I fail to see the case for the additional cost no matter how small. Then again, if it fits into 300-500 MB of storage space then the speed of the flash storage won't be an issue, but still why throw in additional costs when in that case a mechanical HDD would do just as well.

Cheap tablets and smartphone use flash mainly because of the size and power use. Speed of the storage used is dog slow. But when your apps are generally a few 10's of MBs in size even 20 MB/s transfer speeds will load it up quickly.

Regards,
SB

 

[MrFox]

I'm not talking about interleaving writes combined with reads. You have to interleave reads in order to get good read performance.

You mean bank interleaving inside the chip? What's expensive about that? The bank interleaving is internal, it isn't any more complex than swapping the chip-select bits inside the address space.

As well their own product information lists 1500 random IOPS, decent but not great. And that's for the expensive one.

No, you're wrong. It's 3500 read iops. 140MB/s read. That's also the last-year part, samsung is gloating that they now own the eMMC market for smartphone and tablets because they are much faster than the competition. This product line targets the tablet and smartphone market. It won't be expensive as you claim. Cost is determined by die size and production volume.

The one that would most likely be featured in a console that isn't trying to bankrupt the company would likely be the KLMAG2WE4A (250 IOPS) or KLMAG2GE4A (400 IOPS) both of which would actually be slower than pretty much all modern day 5400 RPM HDDs. And they would STILL be more expensive.

No. That's 400 iops in WRITE. The JEDEC class is the write iops. Samsung's controllers read 2.5x that number. That's 1000 iops for the mid-range chip, and about 50MB/s, where have you seen a 1ms 5400 laptop HDD?

 

[Silent_Buddha]

You mean bank interleaving inside the chip? What's expensive about that? The bank interleaving is internal, it isn't any more complex than swapping the chip-select bits inside the address space.

That's where you are wrong. Even their eMMC uses 8 flash chips per package.

Feel free to link me to their documentation. I did a cursory look at their site and that's what I pulled up for the model number you gave me. And that was for Read IOPs. Even better would be a link to actually product with benchmarks at an external site. Granted that is difficult for eMMC based drives if they aren't used in a PC. Especially since manufacturer specs are rarely even close to what is achieved in the real world. The Intel 520 for example quotes a read IOPS of 50k. In the real world workloads (read non-enterprise) it struggles to top 12K IOPS (drops dramatically for lower capacity drives). The same is true for eMMC devices, where manufacturer quoted IOPS are only attainable in synthetic benchmarks.

For a mobile device it is irrelevant whether it can reach the quoted IOPS since the demand on the storage subsystem isn't going to be very high regardless.

Regards,
SB

 

[MrFox]

That's where you are wrong. Even their eMMC uses 8 flash chips per package.

I'm not wrong. My sentence was factual. I didn't claim there weren't multiple dies.

Call it chip-select or bank-select. It's the same thing for all intent and purpose. I claim the interleaving is across banks, who cares if it's 2 dies of 32 banks, or 4 smaller dies of 16 banks? It's the number of banks that matters, and the interface.

The chip I mention is a dual-die package.
The 12GB PS3 is using the KLMAG2GE4A, which is basically the class400 version, also dual-die, the dies are a bit smaller, so a bit less expensive (die size == cost).
Benchmarks are showing the 12GB to be faster loading games than the HDD version. So it's not slower than a 5400 HDD. For an OS, the iops will be king.

 

[Cyan]

Gaffer rykomatsu translated the Watch Cerny interview:

That's quite an interesting interview, especially where he mentions the different customizations they've made to make the machine even more efficient. It shows how Sony devoted their time to further improving the capabilities of the console via smart design rather than trying to make it run super hot and so on.

 

[rockaman]

There's no reason to believe sony would reason any different than nintendo here. They sure as hell didn't with the PS3; updating its firmware takes fecking forever. Nobody would cheer them for paying extra for the super fast class of flash devices except the fanboys, who mindlessly cheer them on regardless of everything anyway.

That was 7 years ago... different time, different place. Hard to predict the future of networking, unless you have 20/20 hindsight. No console had a perfect OS back from 2006.

 

[Brad Grenz]

Am I? A cheap SSD featuring slow speeds and old controllers can get down to around 0.70 USD per GB which is a whole lot cheaper than it was 2 years ago. That's for a 240-256 GB device, the sweet spot with regards to pricing. Drop down to low capacity SSDs and the price per GB goes up drastically to about 1.56 USD. Over double the cost per GB. And that's for a 32 GB device. Drop down to a 16 GB SSD and the price per GB would go up even more (likely into the 3.00 USD per GB range) if they were actually made.

Compare that to HDDs. The sweet spot is 3 TB 3.5" drives at about 0.045 USD per GB. 3.5" drives aren't likely to appear in a console however. So, looking at 2.5" drives the sweet spot for pricing is at the 1 TB level where it's about 0.08 USD per GB. And just as with flash drives as capacity goes down, price per GB goes up. A 500 GB 2.5" drive (as rumored for Durango) goes for about 0.12 USD per GB.

So, yes, I was exaggerating a bit with orders of magnitude. But it certain is more than an order of magnitude more expensive.

Now if you don't mind dropping the speed drastically by using a USB key flash controller or a cheap eMMC package you can lilely keep the price of 16 GB of storage to around 1.00 USD per GB or lower depending on how slow you want the device to be. And at that point you're going to likely be slower than a mechanical HDD anyway while paying more per GB.

I paid $80 for a top rated Samsung 128gb ssd last year. 256gb models routinely sell for about $140. Obviously it doesn't compare to a mechanical hdd, but the point is if Sony's OS to needs a patch of high quality flash it won't break the bank. Sub $10 for 16gb is realistic.

 

[patsu]

The OS should be relatively small. When PS3 was launched, the OS and built-in apps were all in the Flash RAM. They eventually reduced the Flash size and migrated stuff to the HDD over time. The team was probably swarmed at that time.

If the 16GB rumor were true, then I hope it's used to facilitate BR reading/streaming, app switching, and partial install (working buffer).