By: wumpus (lost.delete@this.in.a.cave), April 19, 2019 6:50 am
Room: Moderated Discussions
anon (spam.delete.delete.delete@this.this.this.spam.com) on April 19, 2019 2:03 am wrote:
> PiedPiper (not.delete@this.likelyh.com) on April 18, 2019 7:33 pm wrote:
> >
> > > Are we looking at the same specs? It says 3500 MB/s for both for me.
> > > Either way that's limited more by the controller, the number of chips and the interface rather
> > > than the NAND. They could surely build a controller that would squeeze more out of the MLC, but
> > > what use is a controller that can get 5000-6000 MB/s read speeds with a PCIe 3.0 x4 interface?
> >
> > given we know it's zen 2, i'm pretty sure it would be PCIe 4.0
> > x4, which changes the max theoretical BW discussion a lot.
>
> I was refering to current SSDs where theoretically the MLC/TLC NAND would be faster than QLC, it just makes
> no sense to beef up the controller for that when you're limited to less than 4000 MB/s by the interface,
> resulting in realistically ~3500 MB/s. Of course that changes with PCIe 4.0, but the argument that TLC and
> QLC both offer the exact same read speed because they can both saturate PCIe 3.0 x4 is bullshit.
>
> But yes, that could be the marketing speak. Ignore the existence of SSD PCIe cards, ignore
> the fact that PCIe 4.0 x4 will be available for PCs before that console launches and just
> claim that you've got "more raw bandwidth than anything available for PC right now". Sounds
> better than "next year we'll have what PCs will have this year" but isn't.
I think the argument is that QLC storage that can saturate a PCIe 3.0 bus is "good enough" for plenty of otherwise insurmountable problems (loading times, streaming incoming assets for things like Spiderman flying through a city).
Cost and the inevitable much bigger storage requirements can't be ignored. PS5 appears to be going for 4k (with rumors of 8k) resolution and 4k texture DLCs have been seen doing 50G on their own. Building a PS4 sized storage unit is fine for playing PS4 games, but once developers stretch their legs in a 4k world, you are going to need a much bigger storage system.
Marketing is going to marketspeak. Engineers have to balance many things, and storage size is going to be as important as speed (and cost is always a spec). PC NVMe speed is high enough that it is unlikely that anyone will tell the difference between NVMe drives while gaming (especially if they can saturate 4xPCIe3.0).
> PiedPiper (not.delete@this.likelyh.com) on April 18, 2019 7:33 pm wrote:
> >
> > > Are we looking at the same specs? It says 3500 MB/s for both for me.
> > > Either way that's limited more by the controller, the number of chips and the interface rather
> > > than the NAND. They could surely build a controller that would squeeze more out of the MLC, but
> > > what use is a controller that can get 5000-6000 MB/s read speeds with a PCIe 3.0 x4 interface?
> >
> > given we know it's zen 2, i'm pretty sure it would be PCIe 4.0
> > x4, which changes the max theoretical BW discussion a lot.
>
> I was refering to current SSDs where theoretically the MLC/TLC NAND would be faster than QLC, it just makes
> no sense to beef up the controller for that when you're limited to less than 4000 MB/s by the interface,
> resulting in realistically ~3500 MB/s. Of course that changes with PCIe 4.0, but the argument that TLC and
> QLC both offer the exact same read speed because they can both saturate PCIe 3.0 x4 is bullshit.
>
> But yes, that could be the marketing speak. Ignore the existence of SSD PCIe cards, ignore
> the fact that PCIe 4.0 x4 will be available for PCs before that console launches and just
> claim that you've got "more raw bandwidth than anything available for PC right now". Sounds
> better than "next year we'll have what PCs will have this year" but isn't.
I think the argument is that QLC storage that can saturate a PCIe 3.0 bus is "good enough" for plenty of otherwise insurmountable problems (loading times, streaming incoming assets for things like Spiderman flying through a city).
Cost and the inevitable much bigger storage requirements can't be ignored. PS5 appears to be going for 4k (with rumors of 8k) resolution and 4k texture DLCs have been seen doing 50G on their own. Building a PS4 sized storage unit is fine for playing PS4 games, but once developers stretch their legs in a 4k world, you are going to need a much bigger storage system.
Marketing is going to marketspeak. Engineers have to balance many things, and storage size is going to be as important as speed (and cost is always a spec). PC NVMe speed is high enough that it is unlikely that anyone will tell the difference between NVMe drives while gaming (especially if they can saturate 4xPCIe3.0).
