PCIe 4.0 implementation plan

[Scorpio187]

It took more than 4 years before PCIe 3.0 SSDs started become more or less widespread. How long do you think it will take for PCIe 4.0 to become widespread on (at least on consumer level) given the final specifications are expected to be released in 2017?

Also, how fast is this baby going to be? Given that the current sequential read speed on Samsung 950 Pro reaches 2.5 GB/s, can it be twice as fast?

 

[Deders]

PCIe 3 still has plenty of bandwidth available. A PCIe 3.0 4x connection can provide 4GB/s each way, totalling 8GB/s.

 

[Scorpio187]

PCIe 3 still has plenty of bandwidth available. A PCIe 3.0 4x connection can provide 4GB/s each way, totalling 8GB/s.

I'm not tech savyy, but this is what I find confusing. How come a laptop that is equipped with PCIe 3.0 x 4 SSD can only reach (considering that PCIe 3.0 speed per lane equals 985 MB/s (×1)) from 1GB/s - 2.5GB/s? I'm not tech savyy as you can see, but I'd love clarification on this subject.

 

[Deders]

It's a limitation of the drive itself.

It's always been that way with IDE and Sata. Just because a Sata3 interface can allow up to 600MB/s (more like 550MB/s) Doesn't mean that the drive itself can supply that much data.

 

[Scorpio187]

O, I see. So do you think we'll start seeing PCIe 3.0 SSDs with read/write speed exceeding that of 950 pro in the near future? Also, what do you imagine the minimum speed of PCIe 4.0 SSD drives would be?

 

[jpiniero]

The future of storage (at the high end, on Intel at least) is 3DXP DIMMs. It'd be way faster than the PCIe interface by using the memory controller on the CPU. How realistic the pricing will be is an open question plus you will need an Intel processor that supports it.

 

[Scorpio187]

Aah yes, the 3D XPoint. I wonder how fast this beast is going to be.

 

[tcsenter]

I'm not tech savyy, but this is what I find confusing. How come a laptop that is equipped with PCIe 3.0 x 4 SSD can only reach (considering that PCIe 3.0 speed per lane equals 985 MB/s (×1)) from 1GB/s - 2.5GB/s? I'm not tech savyy as you can see, but I'd love clarification on this subject.

Laptop makers often reduce speeds intentionally to be more power efficient or reduce thermal dissipation. e.g. Macbooks used to limit SATA 3Gbps ports (internal) to 1.5Gbps for this reason. Each spec doesn't mandate the highest speed be utilized. e.g. a company can claim it's device is PCI-E 2.0 but actually implements 1.0 frequency/signaling with 2.0 protocol/encoding.

 

[Scorpio187]

Interesting. I didn't know that.

 

[Magic Carpet]

n/m.

 

[shabby]

Aah yes, the 3D XPoint. I wonder how fast this beast is going to be.

Intel mentioned it'll be slower than current dimm's since they plan to release it as an ssd and a dimm. So it'll be the fastest ssd out there at a premium price, but the cheapest high capacity dimm due to its slower speed... something along these lines.