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fatslob-:O on 18 February 2018
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Intrinsic said:

fatslob-:O said:

In terms of memory bandwidth, it's absolutely top notch and I don't wish for 4K, I wish for physically based dynamic global illumination ... (BW might become a severe bottleneck when doing ray traversal in ray tracing so I want this mitigated as soon as possible for next generation) 

Also the difference is much larger than 50 GB/s. The fastest HBM 2 memory module can let us achieve rates as high as 1.25 TB/s on a 4096-bit bus width while the maximum a GDDR6 standard memory module can achieve on a 512-bit bus width will net 1 TB/s. GDDR6 has a massive 20% BW deficit compared to the fastest HBM 2 memory module ... 

No....

16GB of GDDR6 with 256-bit bus = 576GB/s.

24GB of GDDR6 with 384-bit bus = 864GB/s 

I can't say anything about what GDDR6 on a 512-bit bus would reach but instead I ask this. At 864GB/s we are looking at bandwidth more than 4 times whats in the PS4 today. You really think we need that much bandwidth in a console to push 4k games? I doubt. HBM would be great... but its just not necessary.

Even after using Samsung's 18 Gbps GDDR6 modules, it still won't hold a candle to HBM 2 ... 

We don't need 4K for next generation, we need something far more and that physically based dynamic global illumination ... 

Pemalite said:

Well. GDDR5X protocol and interface training sequence are similar to those of the GDDR5, but adopts the 16n prefetch that GDDR6 is adopting.
We could say it is an extension of GDDR5 rather than something new, the name of the DRAM backs that up.

It mostly existed because GDDR6 was so late to the table, we needed an interim solution.

I'm just going to take a wait-and-see approach on GDDR7, if we get it before 2020 then great.

GDDR5X is most definitely a different standard from GDDR5. Both have different physical packaging and GDDR5X operates at lower voltages too so it is not some extension. A hardware vendor can't just slot in a GDDR5X module in place of a GDDR5 module and that's partially why AMD is in a bind since they didn't design Vega to be compatible with GDDR5X so we're either going to have to wait until the 2nd gen Vega comes or if not that then Navi ... 

Personally I hope we get GDDR7 standard finalized in 2020 for a 2021 release so console hardware manufacturers can use it if they launch their consoles during that year ... 

Pemalite said:

GDDR6 is cheaper though for it's given capacity, which is why it will be leveraged for next-gen.
Unless GDDR7 is ramped up before then, but I have my doubts.

With that in mind... If AMD drives home the memory controller, I am sure they could push the bandwidth, AMD and nVidia pushed GDDR5 to it's absolute limits, power consumption be damned even.

If we can't get GDDR7 then hopefully they make do with just GDDR6X by just doubling the bandwidth and not touching the densities. I'd be content with just 16GB with 4 GB of DDR5 dedicated to the whole background ... 

8 Zen 3+ cores (with AVX-512 + TSX), successor to Navi microachitecture and at least 1 TB/s (wanted 2 TB/s) for PS5 should be the baseline ... (next generation could be our last one)