Upgrading to SSD's for PS4, an awful choice?

[-tkf-]

Ahh, you caught me.

Still, I'd feel better about explicit support to keep it at top performance.

With the right drive the difference will be small and compared to a mechanical drive still far far better.. depending on how the PS4 makes use of the extra speed of course, the PS3 had a bottleneck somewhere that limited the benefit of SSD.

 

[Silent_Buddha]

Yeah, I'd be weary of sticking a smaller SSD into a PS4 without TRIM as if you full it up, you can easy turn into a worse performer than a mechanical drive. The OS will also do HDD defragmentation which harms the lifespan of an SSD. And the constant recording feature isn't too SSD-friendly either.

That depends on the PS3's OS actually supporting TRIM. If it doesn't then it doesn't matter if an SSD has it or not. And at this point who knows whether Sony has support for TRIM in the OS. Since it's going to come with a mechanical HDD, the limited development time they have available makes it highly unlikely it'll be included at launch. Just look at how long it took for Apple to finally put TRIM support into OSX and they have full time OS developers.

"Easy", if you run constant random write benchmarks on the drive, yes. Not just by sticking it in a console and using it normally; the drive's own garbage collection mechanism will be quite capable of keeping it fit.


Not necessarily, since SSDs can be detected by the console firmware (if supported.) In any case, some spurious writes won't do much in the way of lifespan reduction.


Doesn't really matter. It's pretty much impossible to actually wear out even a small SSD with normal use. The recording bitrate is too low to wreck the drive in any reasonable amount of time.

Assuming Sony weren't lying and they are constantly recording the last 15 minutes of video that represents a constant stream of writes to the drive. For a mechanical drive that's no big deal. For an SSD that's a potential problem if the system doesn't support TRIM. And depending on the quality of the recorded video that could potentially pose a long term problem for drives with lower endurance. Play for 3 hours and that's 3 hours of video that has potentially been written to the drive. At 1080p that's potentially 4-5 GB per hour at decent quality.

But perhaps they'll limit the always on recording to 720p at streaming friendly bitrates at which point it won't be nearly as much of an issue.

And garbage collection doesn't occur on SSDs until X amount of storage idle time has accrued. If the system is constantly accessing the drive whether to record game video or any other game/system access then GC won't happen.

As long as you leave some amount of unused space on the drive then it shouldn't be much of a problem. For smaller drives though it becomes far more likely for a user to fill the drive or nearly fill the drive at which point it becomes a problem and you're likely to hit the worst case scenario for drive performance.

Regards,
SB

 

[-tkf-]

That depends on the PS3's OS actually supporting TRIM. If it doesn't then it doesn't matter if an SSD has it or not. And at this point who knows whether Sony has support for TRIM in the OS. Since it's going to come with a mechanical HDD, the limited development time they have available makes it highly unlikely it'll be included at launch. Just look at how long it took for Apple to finally put TRIM support into OSX and they have full time OS developers.

Assuming Sony weren't lying and they are constantly recording the last 15 minutes of video that represents a constant stream of writes to the drive. For a mechanical drive that's no big deal. For an SSD that's a potential problem if the system doesn't support TRIM. And depending on the quality of the recorded video that could potentially pose a long term problem for drives with lower endurance. Play for 3 hours and that's 3 hours of video that has potentially been written to the drive. At 1080p that's potentially 4-5 GB per hour at decent quality.

But perhaps they'll limit the always on recording to 720p at streaming friendly bitrates at which point it won't be nearly as much of an issue.

And garbage collection doesn't occur on SSDs until X amount of storage idle time has accrued. If the system is constantly accessing the drive whether to record game video or any other game/system access then GC won't happen.

As long as you leave some amount of unused space on the drive then it shouldn't be much of a problem. For smaller drives though it becomes far more likely for a user to fill the drive or nearly fill the drive at which point it becomes a problem and you're likely to hit the worst case scenario for drive performance.

Regards,
SB

Netflix streams HD at around 3.2GB pr hour. Let's pretend that it's actually 5 GB pr hour as you suggested,

Taking from this: http://www.anandtech.com/show/6459/samsung-ssd-840-testing-the-endurance-of-tlc-nand

You can write 10GiB pr day for 35 years or 30GiB for over 10 years, or maybe i am reading it wrong?. Which would require 6 hours of constant playing every day. Garbage collection is a unknown, but i would guess that since the PS4 is designed to be "Green" it doesn't keep it's harddrive active all the time.

 

[dagamer]

Netflix streams HD at around 3.2GB pr hour. Let's pretend that it's actually 5 GB pr hour as you suggested,

Taking from this: http://www.anandtech.com/show/6459/samsung-ssd-840-testing-the-endurance-of-tlc-nand

You can write 10GiB pr day for 35 years or 30GiB for over 10 years, or maybe i am reading it wrong?. Which would require 6 hours of constant playing every day. Garbage collection is a unknown, but i would guess that since the PS4 is designed to be "Green" it doesn't keep it's harddrive active all the time.

System performance suffers terribly if a drive doesn't have TRIM commands sent. Remember that the drive isn't aware of what blocks are free until the OS tells it so with every new write command, it will keep writing to a new location not considering what the OS thinks is free. The Nexus 7 (2012) had this very issue until Android 4.3 solved it. You also start getting into problems with write amplification when you consider that most SSDs are rather small for the price compared to a 2.5" drive. Sony has already said that the PS4 will pre-cache games it thinks you might want to purchase putting more stress on the system. A hard drive and an SSD shouldn't be treated the same.

I wouldn't stick an SSD into a PS4 until Sony explicitly supports it. I'm not worried about the drive dying, but it's actually pretty easy to give it bad conditions to operate under (and if you try to get a drive that does garbage collection on its own like a SandForce drive, it also doesn't like dealing with non-compressible data like video streams).

 

[Grall]

that represents a constant stream of writes to the drive.

Not constant per se, it'd be a slow, bursty trickle of writes really.

For an SSD that's a potential problem if the system doesn't support TRIM.

Not really, at the low load a console would put on the drive. It's not a file or database server being run on the drive. It'd manage just fine unless the drive firmware is horribly broken.

And garbage collection doesn't occur on SSDs until X amount of storage idle time has accrued.

It'll happen when it runs out of spare area, regardless of how long since last write occurred, but if you're only writing on the order of a few gigs per HOUR at most (remember, this feature is intended for streaming across highly asymmetrical DSL connections and whatnot so it won't be very high bitrate), you won't notice any slowdown at all when you're writing while the drive garbage collects.

For smaller drives though it becomes far more likely for a user to fill the drive or nearly fill the drive at which point it becomes a problem and you're likely to hit the worst case scenario for drive performance.

Bah. No. You're only going to trip up a decent SSD into a worst-case scenario by pounding it with random writes. A video ring buffer would be anything but random, really. And these days, pretty much anything you can buy for money should be decent or better. Maybe stay away from the no-name, small bit-players, you'll be fine.

No need to be a worry wart, a console is a low-load environment.

 

[Silent_Buddha]

Not really, at the low load a console would put on the drive. It's not a file or database server being run on the drive. It'd manage just fine unless the drive firmware is horribly broken.

Considering that even something as simple as web browsing can trip up a drive without TRIM causing stuttering performance in the OS, it is certainly much more possible with constant writes to the disk from recording video. This happens even with modern SSDs as evidenced when people put them into Mac's before TRIM was supported. As I said, leaving a large reserve of unused space could get around that for most people as then you don't trigger block erase then write (which causes the stuttering performance) since you are less likely to fill the drive before it can do GC during idle time.

It'll happen when it runs out of spare area, regardless of how long since last write occurred, but if you're only writing on the order of a few gigs per HOUR at most (remember, this feature is intended for streaming across highly asymmetrical DSL connections and whatnot so it won't be very high bitrate), you won't notice any slowdown at all when you're writing while the drive garbage collects.

Triggering a block erase/write cycle while the data is being written to the drive will cause the OS to pause (causing the stuttering mentioned above) whenever this happens. If the drive features a lot of DRAM cache then this generally only happens if you have more writes than can be held in cache and written to disk before the next write request arrives. For older drives caches were quite small and hence you had pauses of up to 30 seconds or more for first gen SSDs. Modern SSDs feature larger caches, but you can still trigger the behavior with simple web browsing if the drive is required to do block erase/write whenever a write request comes in. That is why TRIM, even on modern drives is absolutely essential for smooth and consistent performance.

That is why GC is only done during drive idle time. As an example, one recent drive, the Crucial M500, has an extremely aggressive GC algorithm and it directly impacts performance of the drive. Although thankfully not in catastrophic ways. From the Anandtech review of the Samsung 840 EVO.

Sequential read and write performance, even at low queue depths is very good on the EVO. You may notice lower M500 numbers here than elsewhere, the explanation is pretty simple. We run all of our read tests after valid data has been written to the drive. Unfortunately the M500 attempts to aggressively GC data on the drive, so even though we fill the drive and then immediately start reading back the M500 is already working in the background which reduces overall performance here.

And the reason it isn't catastrophic is because it isn't attempting to do it while writes are pending.

Regards,
SB

 

[MrFox]

PS4 OS is a modified version of FreeBSD, which already supports TRIM, so it's just a question of Sony enabling it and testing it.

 

[-tkf-]

Considering that even something as simple as web browsing can trip up a drive without TRIM causing stuttering performance in the OS, it is certainly much more possible with constant writes to the disk from recording video. This happens even with modern SSDs as evidenced when people put them into Mac's before TRIM was supported. As I said, leaving a large reserve of unused space could get around that for most people as then you don't trigger block erase then write (which causes the stuttering performance) since you are less likely to fill the drive before it can do GC during idle time.



Triggering a block erase/write cycle while the data is being written to the drive will cause the OS to pause (causing the stuttering mentioned above) whenever this happens. If the drive features a lot of DRAM cache then this generally only happens if you have more writes than can be held in cache and written to disk before the next write request arrives. For older drives caches were quite small and hence you had pauses of up to 30 seconds or more for first gen SSDs. Modern SSDs feature larger caches, but you can still trigger the behavior with simple web browsing if the drive is required to do block erase/write whenever a write request comes in. That is why TRIM, even on modern drives is absolutely essential for smooth and consistent performance.

That is why GC is only done during drive idle time. As an example, one recent drive, the Crucial M500, has an extremely aggressive GC algorithm and it directly impacts performance of the drive. Although thankfully not in catastrophic ways. From the Anandtech review of the Samsung 840 EVO.



And the reason it isn't catastrophic is because it isn't attempting to do it while writes are pending.

Regards,
SB

It will take something special to make it a problem for PS4 owners with SSD drives. First they need the drive to be full, second they need to constantly be using the console in such a way that it writes and read constantly to the disc if GC isn't going to work.

And the real issue will afaik raise it's head during writes, which there isn't alot of on a console except for the streaming thing (few mbits) and download (few mbits). The classic SSD "stutter" is unlikely to show it's head in such a way it can be seen. It's not like we copy Gigs of data from one drive to another. Most of the data on the SSD is very static.

However, thanks to the possibility of actually using a SSD drive the daily usage of the PS4 can be accelerated to unseen heights in the console world. Loading times for games, apps browsers etc could be almost instant compared to the mechanical drive. I had the pleasure of trying the Harddrive Boot CD for the original PS2, it was pretty crazy the difference it made. If SSD's aren't bottleneck'd like they were on the PS3 it's going to be a nice plus for those that can afford it.

 

[Silent_Buddha]

It will take something special to make it a problem for PS4 owners with SSD drives. First they need the drive to be full, second they need to constantly be using the console in such a way that it writes and read constantly to the disc if GC isn't going to work.

And the real issue will afaik raise it's head during writes, which there isn't alot of on a console except for the streaming thing (few mbits) and download (few mbits). The classic SSD "stutter" is unlikely to show it's head in such a way it can be seen. It's not like we copy Gigs of data from one drive to another. Most of the data on the SSD is very static.

However, thanks to the possibility of actually using a SSD drive the daily usage of the PS4 can be accelerated to unseen heights in the console world. Loading times for games, apps browsers etc could be almost instant compared to the mechanical drive. I had the pleasure of trying the Harddrive Boot CD for the original PS2, it was pretty crazy the difference it made. If SSD's aren't bottleneck'd like they were on the PS3 it's going to be a nice plus for those that can afford it.

It's difficult to say. If Sony are going with apps, web browsing, video streaming, etc. Then there are going to be quite a few writes to the drive.

With proper TRIM support it's unlikely to fill a drive with daily activities that push it into the really bad performance state (having to do block erase/write at the time data is written to the drive). Without proper TRIM support the only way to potentially avoid this is to have extremely aggressive GC like the M500 which directly impacts read performance to some degree (GC is suspended when writes are occurring so as not to trigger catastrophic performance decline).

Obviously if you have a 250 GB SSD and only keep 175 GB of data on it at any given time it'll be difficult to trigger a worst case scenario under normal use conditions assuming the system has sufficient idle time to do GC. That becomes a problem though if a person has say a 64 GB or 128 GB SSD and only leaves 5 GB (as an example) free in order to make the most of their relatively expensive storage purchase (the same amount of money for a 64 GB SSD can buy you a 1 TB HDD). It doesn't take much web browsing or video streaming at that point to trigger block erase/write cycles while a write request is pending. That's without proper TRIM support. Although in the latter case of only a small amount of free space, even TRIM may not be entirely sufficient if writes are constant as the drive may not have sufficient drive idle time to block erase cells that have been marked as deleted before the next write request arrives.

It just depends on how much and how often data is written to the drive at that point. Although if you're that low on storage space, hopefully the PS4's OS is smart enough to disable or reduce the 15 minute automatic game video recording.

Regards,
SB

 

[-tkf-]

It's difficult to say. If Sony are going with apps, web browsing, video streaming, etc. Then there are going to be quite a few writes to the drive.

With proper TRIM support it's unlikely to fill a drive with daily activities that push it into the really bad performance state (having to do block erase/write at the time data is written to the drive). Without proper TRIM support the only way to potentially avoid this is to have extremely aggressive GC like the M500 which directly impacts read performance to some degree (GC is suspended when writes are occurring so as not to trigger catastrophic performance decline).

Obviously if you have a 250 GB SSD and only keep 175 GB of data on it at any given time it'll be difficult to trigger a worst case scenario under normal use conditions assuming the system has sufficient idle time to do GC. That becomes a problem though if a person has say a 64 GB or 128 GB SSD and only leaves 5 GB (as an example) free in order to make the most of their relatively expensive storage purchase (the same amount of money for a 64 GB SSD can buy you a 1 TB HDD). It doesn't take much web browsing or video streaming at that point to trigger block erase/write cycles while a write request is pending. That's without proper TRIM support. Although in the latter case of only a small amount of free space, even TRIM may not be entirely sufficient if writes are constant as the drive may not have sufficient drive idle time to block erase cells that have been marked as deleted before the next write request arrives.

It just depends on how much and how often data is written to the drive at that point. Although if you're that low on storage space, hopefully the PS4's OS is smart enough to disable or reduce the 15 minute automatic game video recording.

Regards,
SB

Hopefully they allocate the needed space for recording pr default, anything else would be stupid. And anyone that replaces a 512GB drive with a 64GB drive is asking for trouble. Just as the OS take a chunck of the ram, i expect it to take a healthy bit of the hard drive as well.

I am almost certain that the people that goes for SSD will never experience the problems you create, it's to far fetched to expect the PS4 OS to be a constant writing machine to such a degree that a SSD will never be able to garbage collect.

And again, they only critical write procedure is game recording, and even if the drive is filled to the brim, that space will be pre-allocated and not requiring any kind of high speed writes. And as i said, afaik read speed has nothing to do with the lack of GC collection, which is the important part..

 

[dagamer]

I only trust 3 companies at this point to write a general purpose OS, Microsoft, Apple and Google. Sony doesn't inspire confidence with their software.

 

[Shifty Geezer]

What was wrong with PS2 and PS3 and PSP and PSV OSes?

 

[Pressure]

I think what we are forgetting at this point, is that even if the Solid State Disk has to issue TRIM commands at the same time as writing to the drive, it will still be an order of magnitude faster than the old crummy mechanical hard drive.

I'm still rockin' an old, first generation Intel X-25M without support for TRIM from 2008 (50nm MLC) and it works just fine.

 

[dumbo11]

I only trust 3 companies at this point to write a general purpose OS, Microsoft, Apple and Google. Sony doesn't inspire confidence with their software.

"Microsoft entertainment division" didn't write windows 8, and "Sony console division" did not write BSD.

Anyway, I'd imagine that Sony are mostly interested in creating a 'slim' UI wrapper/app on top of BSD - they won't need to truly fork BSD as Apple did (twice?) or fork linux as google did.

 

[Silent_Buddha]

I think what we are forgetting at this point, is that even if the Solid State Disk has to issue TRIM commands at the same time as writing to the drive, it will still be an order of magnitude faster than the old crummy mechanical hard drive.

I'm still rockin' an old, first generation Intel X-25M without support for TRIM from 2008 (50nm MLC) and it works just fine.

The X-25M was definitely good but that was because they reserved a lot of NAND storage for the purposes of smooth operation. In general about 6-7.5%. The 80 GB drive had ~6-6.5 GB of NAND storage that was only available to the drive's firmware. If it got into a situation where the 80 GB user addressable space was full, it could still schedule writes to that reserve space. Then it could do GC when time permitted. Most competing drives at the time had no reserve space, which when combined with the crappy Jmicron controllers that most used at the time, lead to some really horrendous situations.

For most users that was sufficient to avoid a worst case scenario. But it was still possible to run it into a corner and trigger stuttering performance. I've done it before myself when I didn't pay attention and allowed the drive to mostly fill up with un-eraseable data and then went on a research binge on the web. Hello, OS pause and stutter.

The X25-M G2 came with TRIM which pretty much removed most corner cases when combined with an OS that supported TRIM, however.

Good drive for sure though. And you paid for it.

Regards,
SB

 

[dumbo11]

An interesting question is whether you could shove 1+GB of volatile memory onto a USB stick (and have it pretend to be a standard SSD).

Alternatively, a standard drive with an oversized buffer configured properly might do the same job... interesting.

 

[Grall]

I'm still rockin' an old, first generation Intel X-25M without support for TRIM from 2008 (50nm MLC) and it works just fine.

Yeah, and I used an X-25E (also without trim, because intel was too cheap to back-implement it on their older line of drives) for ~four years straight without any noticeable performance degradation whatsoever. Recently I wiped it and updated the firmware, then reinstalled win7 on it, so now it's essentially reset back to factory performance. Not that I ever noticed any difference mind you... It could copy large data files at ~120MB/s (reading and writing to the same drive simultaneously) after years of daily use, so lack of trim really isn't such a big deal as some are making it out to be.

 

[Silent_Buddha]

Yeah, and I used an X-25E (also without trim, because intel was too cheap to back-implement it on their older line of drives) for ~four years straight without any noticeable performance degradation whatsoever. Recently I wiped it and updated the firmware, then reinstalled win7 on it, so now it's essentially reset back to factory performance. Not that I ever noticed any difference mind you... It could copy large data files at ~120MB/s (reading and writing to the same drive simultaneously) after years of daily use, so lack of trim really isn't such a big deal as some are making it out to be.

The X25-E used SLC which has a significantly lower block erase penalty than MLC as well as ~2.5x the write speed of MLC.

That made it almost impossible to trigger the catastrophic write penalties that could happen with MLC based drives if you got into a situation where it had to do a block erase before it could write data. Hence TRIM doesn't benefit SLC drives in the same way that it does for MLC drives.

But the drawback of course is price. At launch an X25-E with 32 GB had an MSRP of 695 USD compared to an X25-M with 80 GB with an MSRP of 595 USD.

Regards,
SB

 

[-tkf-]

The X25-E used SLC which has a significantly lower block erase penalty than MLC as well as ~2.5x the write speed of MLC.

That made it almost impossible to trigger the catastrophic write penalties that could happen with MLC based drives if you got into a situation where it had to do a block erase before it could write data. Hence TRIM doesn't benefit SLC drives in the same way that it does for MLC drives.

But the drawback of course is price. At launch an X25-E with 32 GB had an MSRP of 695 USD compared to an X25-M with 80 GB with an MSRP of 595 USD.

Regards,
SB

So do you actually think that a modern ssd will be slower than a mechanical 2.5 drive in a ps4 at some point. I am just wondering what real life scenario that would have to happen for this to happen. We are talking about writes, right? When do you see a ssd being outpaced by a mechanical 2.5 drive, is there even any examples with modern ssd where this can be shown?

 

[Grall]

So do you actually think that a modern ssd will be slower than a mechanical 2.5 drive in a ps4 at some point.

Impossible. There just won't be enough writes shoved onto to the drive to wear it down like that.