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Forums - Gaming Discussion - I/o throughput vs memory bandwidth

Some one please explain the difference and what they both mean for next gen gaming, cheers.



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If you have to ask it already means absolutely nothing to you.

Memory bandwidth is the maximum theoretical speed at which memory(RAM) can be read. So the theoretical speed at which a CPU or GPU can retrieve data from memory. It's important to keep the processor fed with data, because if it is too slow the whole process will stall because the processor processes data faster than it can retrieve it and has to wait for new data. In games that would result in stutter or lower framerates. More bandwidth is better but it is NOT a direct indicator of overall performance, since a game can also be bottlenecked at the processor, which is usually the case.

I/O throughput is similar. It refers to a specific storage device, which could be RAM or non-volatile storage like an HDD or SSD. Again, also not a direct indicator of performance but higher throughput is always better. As far as I have read it is more used for non-volatile storage. It's more important for next gen because the GPU will be able to directly access the SSD for additional data. However SSDs are much much slower than RAM, so the SSD needs to be as fast as possible to be of use to the GPU.



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I/O throughput is howfast you move (all) data around the entire system. A cool new feature, of these SSD's is they are so fast, they dont have to store as much in Ram, as previous consoles did. You can now load things as needed, and the speed is so fast, its no longer needed to "pre-store" as much. You can even flush things out of system ram, as they go out of view, and load them as your character is turning around ingame, back into ram, because the speed is so fast, without it being noticeable to the player.
This means ram sizes (while just 16GB) actually funktions way above what you would expect, comapired to older consoles. Naturally to take advantage of this, you need a fast SSD and a high I/O throughput (or it would stutter, when you try this).

Memory Bandwidth, is just for your systems ram (in this case).
Its usually used in connection with video cards (because this is where memory bandwidth matters most, for gamers).
Higher resolutions need high amounts of Vram, but also higher memory bandwidth. Picture sizes (4k) requires alot more data moved around, and memory bandwidth matters for this. Basically Memory Bandwidth is required upto a certain point, and the lower resolutions the less the need for high amounts of it, and vice versa.

Look at the Geforce 3070:   448 GB/S memory bandwidth 
Nvidia only gave it 448 GB/s, but thought that was enough for it (with its capabilities). Its about not running into bottlenecks.
How close are the PS5/XSX to this (in terms of performance)? *shrugs*

However it shows the consoles both probably have good enough memory bandwidth for it not to be a issue.


Xbox Series X has "weird" to use memory bandwidth.
Its system ram runs at 2 speeds (10GB at 560GB/s and 6GB at 336GB/s).
If a game needs more than 10 GB of ram to run, the mix-match of the speeds, might result in the PS5 memory bandwidth overall being higher.

Playstation 5's ram all run at the same speed (448GB/s) (so you dont need to worry about, data access levels/requirements, how much Vram games take up ect). It just all works, if you load something into it, while on the XSX the speed differnces might result in issues (depending on how its handled).

Last edited by JRPGfan - on 07 November 2020

Vivster is absolutely on the money.

The lines can be blurred when we start using Ram has a hard drive and a hard drive as Ram.

Essentially a computing system has a hierarchy of memories from fastest+smallest capacity to slowest+largest capacity.
Why do we do this? Cost. That's it. Otherwise we would have entire systems with just L1 cache and nothing else.
And by going with a hierarchy we can mitigate performance penalties.

We go from CPU L1 to L2 to L3 caches which are also in order of size and speed. (Smallest+Fastest)
Then (sometimes) you get L4/eDRAM/eSRAM which is another step up in terms of size, but also a step down in speed.
Ram comes next.... And then your Solid State Drive/Hard Drive... And then lastly your Optical Disk.

The SSD simply is an increase in hard drive bandwidth and latency over the older mechanical drives, it doesn't replace Ram, Ram is still orders of magnitude superior in every single way, except in regards to capacity and being volatile.



--::{PC Gaming Master Race}::--

JRPGfan said:

I/O throughput is howfast you move (all) data around the entire system. A cool new feature, of these SSD's is they are so fast, they dont have to store as much in Ram, as previous consoles did. You can now load things as needed, and the speed is so fast, its no longer needed to "pre-store" as much. You can even flush things out of system ram, as they go out of view, and load them as your character is turning around ingame, back into ram, because the speed is so fast, without it being noticeable to the player.
This means ram sizes (while just 16GB) actually funktions way above what you would expect, comapired to older consoles. Naturally to take advantage of this, you need a fast SSD and a high I/O throughput (or it would stutter, when you try this).

Memory Bandwidth, is just for your systems ram (in this case).
Its usually used in connection with video cards (because this is where memory bandwidth matters most, for gamers).
Higher resolutions need high amounts of Vram, but also higher memory bandwidth. Picture sizes (4k) requires alot more data moved around, and memory bandwidth matters for this. Basically Memory Bandwidth is required upto a certain point, and the lower resolutions the less the need for high amounts of it, and vice versa.

Look at the Geforce 3070:   448 GB/S memory bandwidth 
Nvidia only gave it 448 GB/s, but thought that was enough for it (with its capabilities). Its about not running into bottlenecks.
How close are the PS5/XSX to this (in terms of performance)? *shrugs*

However it shows the consoles both probably have good enough memory bandwidth for it not to be a issue.


Xbox Series X has "weird" to use memory bandwidth.
Its system ram runs at 2 speeds (10GB at 560GB/s and 6GB at 336GB/s).
If a game needs more than 10 GB of ram to run, the mix-match of the speeds, might result in the PS5 memory bandwidth overall being higher.

Playstation 5's ram all run at the same speed (448GB/s) (so you dont need to worry about, data access levels/requirements, how much Vram games take up ect). It just all works, if you load something into it, while on the XSX the speed differnces might result in issues (depending on how its handled).

I highly doubt next gen games will be utilizing the full 16gigs of Ram from a console. Platforms normally disallowed the full use of Ram to be used, as they need dedicated Ram to run the OS and feature sets. I wont be surprised that 6gigs of Ram for the XSX is for the OS etc.

WiiU had 2gigs of Ram, Half of it was used for the WiiU OS (1gig) considering the PS5 and XSX have much more complex OS and more features, expect anywhere near 4gigs for the OS, maybe even more.

https://www.reddit.com/r/wiiu/comments/zz53g/wii_u_ram_capacity_confirmed_1gb_dedicated_to/ 



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Azzanation said:
JRPGfan said:

I/O throughput is howfast you move (all) data around the entire system. A cool new feature, of these SSD's is they are so fast, they dont have to store as much in Ram, as previous consoles did. You can now load things as needed, and the speed is so fast, its no longer needed to "pre-store" as much. You can even flush things out of system ram, as they go out of view, and load them as your character is turning around ingame, back into ram, because the speed is so fast, without it being noticeable to the player.
This means ram sizes (while just 16GB) actually funktions way above what you would expect, comapired to older consoles. Naturally to take advantage of this, you need a fast SSD and a high I/O throughput (or it would stutter, when you try this).

Memory Bandwidth, is just for your systems ram (in this case).
Its usually used in connection with video cards (because this is where memory bandwidth matters most, for gamers).
Higher resolutions need high amounts of Vram, but also higher memory bandwidth. Picture sizes (4k) requires alot more data moved around, and memory bandwidth matters for this. Basically Memory Bandwidth is required upto a certain point, and the lower resolutions the less the need for high amounts of it, and vice versa.

Look at the Geforce 3070:   448 GB/S memory bandwidth 
Nvidia only gave it 448 GB/s, but thought that was enough for it (with its capabilities). Its about not running into bottlenecks.
How close are the PS5/XSX to this (in terms of performance)? *shrugs*

However it shows the consoles both probably have good enough memory bandwidth for it not to be a issue.


Xbox Series X has "weird" to use memory bandwidth.
Its system ram runs at 2 speeds (10GB at 560GB/s and 6GB at 336GB/s).
If a game needs more than 10 GB of ram to run, the mix-match of the speeds, might result in the PS5 memory bandwidth overall being higher.

Playstation 5's ram all run at the same speed (448GB/s) (so you dont need to worry about, data access levels/requirements, how much Vram games take up ect). It just all works, if you load something into it, while on the XSX the speed differnces might result in issues (depending on how its handled).

I highly doubt next gen games will be utilizing the full 16gigs of Ram from a console. Platforms normally disallowed the full use of Ram to be used, as they need dedicated Ram to run the OS and feature sets. I wont be surprised that 6gigs of Ram for the XSX is for the OS etc.

WiiU had 2gigs of Ram, Half of it was used for the WiiU OS (1gig) considering the PS5 and XSX have much more complex OS and more features, expect anywhere near 4gigs for the OS, maybe even more.

https://www.reddit.com/r/wiiu/comments/zz53g/wii_u_ram_capacity_confirmed_1gb_dedicated_to/ 

Microsoft and Sony are reserving more SSD space for OS functions thus they don't need to rely on Ram as heavily...

Thus the Xbox Series X will only use 2.5GB of Ram which is a reduction over the Xbox One.
The Xbox Series S will use only 2GB of Ram which is a reduction again, likely due to the 1080P User Interface rather than 2160P.



--::{PC Gaming Master Race}::--

Pemalite said:
Azzanation said:

I highly doubt next gen games will be utilizing the full 16gigs of Ram from a console. Platforms normally disallowed the full use of Ram to be used, as they need dedicated Ram to run the OS and feature sets. I wont be surprised that 6gigs of Ram for the XSX is for the OS etc.

WiiU had 2gigs of Ram, Half of it was used for the WiiU OS (1gig) considering the PS5 and XSX have much more complex OS and more features, expect anywhere near 4gigs for the OS, maybe even more.

https://www.reddit.com/r/wiiu/comments/zz53g/wii_u_ram_capacity_confirmed_1gb_dedicated_to/ 

Microsoft and Sony are reserving more SSD space for OS functions thus they don't need to rely on Ram as heavily...

Thus the Xbox Series X will only use 2.5GB of Ram which is a reduction over the Xbox One.
The Xbox Series S will use only 2GB of Ram which is a reduction again, likely due to the 1080P User Interface rather than 2160P.

Well thats an improvement, however 2.5gigs is still a fair chunk of Ram.



Azzanation said:
Pemalite said:

Microsoft and Sony are reserving more SSD space for OS functions thus they don't need to rely on Ram as heavily...

Thus the Xbox Series X will only use 2.5GB of Ram which is a reduction over the Xbox One.
The Xbox Series S will use only 2GB of Ram which is a reduction again, likely due to the 1080P User Interface rather than 2160P.

Well thats an improvement, however 2.5gigs is still a fair chunk of Ram.

Imagine we get the slim interface of 360 and ps3 back. They ran at 1080p, less than 64MB for the OS, 32MB even I think at the end of the gen. 2.5 GB, what a waste!



SvennoJ said:
Azzanation said:
Pemalite said:

Microsoft and Sony are reserving more SSD space for OS functions thus they don't need to rely on Ram as heavily...

Thus the Xbox Series X will only use 2.5GB of Ram which is a reduction over the Xbox One.
The Xbox Series S will use only 2GB of Ram which is a reduction again, likely due to the 1080P User Interface rather than 2160P.

Well thats an improvement, however 2.5gigs is still a fair chunk of Ram.

Imagine we get the slim interface of 360 and ps3 back. They ran at 1080p, less than 64MB for the OS, 32MB even I think at the end of the gen. 2.5 GB, what a waste!

Those consoles didn't have a 1080P interface, they were upscaled 720P.
In the Xbox 360's case it's UI was 720P upscaled... But many UI elements were actually 480P like the quick guide menu.

But yeah, they had tiny footprints, by the end of the gen the Xbox 360 was sitting at 24MB and the PS3 at 47MB.

Much of that has to do with how the UI was designed, the Xbox 360's OS used a modular-container approach, so only elements like the video playback engine got loaded into RAM when a user loaded the application, so there was always a delay delving a level deeper into the UI.

The Xbox One by comparison tried to keep as much data in memory as possible so launching an app was a bit snappier.

Next-gen the Xbox Series of consoles will be taking a more Xbox-360-like approach to the OS thanks to the SSD increasing the baseline storage performance.



--::{PC Gaming Master Race}::--

Pemalite said:
SvennoJ said:
Azzanation said:
Pemalite said:

Microsoft and Sony are reserving more SSD space for OS functions thus they don't need to rely on Ram as heavily...

Thus the Xbox Series X will only use 2.5GB of Ram which is a reduction over the Xbox One.
The Xbox Series S will use only 2GB of Ram which is a reduction again, likely due to the 1080P User Interface rather than 2160P.

Well thats an improvement, however 2.5gigs is still a fair chunk of Ram.

Imagine we get the slim interface of 360 and ps3 back. They ran at 1080p, less than 64MB for the OS, 32MB even I think at the end of the gen. 2.5 GB, what a waste!

Those consoles didn't have a 1080P interface, they were upscaled 720P.
In the Xbox 360's case it's UI was 720P upscaled... But many UI elements were actually 480P like the quick guide menu.

But yeah, they had tiny footprints, by the end of the gen the Xbox 360 was sitting at 24MB and the PS3 at 47MB.

Much of that has to do with how the UI was designed, the Xbox 360's OS used a modular-container approach, so only elements like the video playback engine got loaded into RAM when a user loaded the application, so there was always a delay delving a level deeper into the UI.

The Xbox One by comparison tried to keep as much data in memory as possible so launching an app was a bit snappier.

Next-gen the Xbox Series of consoles will be taking a more Xbox-360-like approach to the OS thanks to the SSD increasing the baseline storage performance.

I think the ps3 interface is 1080p, looks sharp to me. The ps3 also had the glass door interface for videos, animated thumbnails, pretty impressive. I still have tons of videos stored on my ps3, all with little clips playing in the menu, so cool. Tech doesn't always get better :/ Game thumbnails were animated as well or at least played music when scrolling over them. The XMB was great, too bad the store was so extremely slow.

I guess most of the reserved RAM nowadays is for always on video recordingand background downloads. The SSD could help reduce the RAM footprint of the OS, but that might take away from the games. They should have had 24 MB RAM, let's see how well the SSD can reduce memory usage from games.