[HN Gopher] SiPearl Lets Rhea Design Leak: 72x Zeus Cores, 4x HB...
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       SiPearl Lets Rhea Design Leak: 72x Zeus Cores, 4x HBM2E, 4-6 DDR5
        
       Author : rbanffy
       Score  : 57 points
       Date   : 2021-02-25 09:53 UTC (13 hours ago)
        
 (HTM) web link (www.anandtech.com)
 (TXT) w3m dump (www.anandtech.com)
        
       | Pet_Ant wrote:
       | >the project uses Arm's upcoming Neoverse "Zeus" cores which
       | succeed the Neoverse N1 Ares cores
       | 
       | Would have much rather seen rise-v for true independence. Maybe
       | the cores will be swappable?
       | 
       | This does seem like legitimately a good case for it with the
       | means to succeed.
        
       | ksec wrote:
       | Need (2020) In the Title.
       | 
       | Also not sure what is worthy of discussions or if there are
       | anything new.
        
         | Google234 wrote:
         | It hasn't been discussed on this site yet so I don't have a
         | problem with the post
        
       | fnord77 wrote:
       | "leak"
        
         | Zenst wrote:
         | Yes, I'm very mindful how companies and politicians have
         | accidents like this - so may well be what I class as "tactile
         | marketing" If we see some share or funding for that company
         | soon, then that would be handy PR then.
         | 
         | [EDIT ADD] Seems they had funding just over a year ago, so be
         | due another round soon I'd expect, that with staggered PR press
         | releases with a slant of European super computer and with that,
         | this leak probably do them more good than harm PR wise - more
         | so if they are in position to be seeking new investment, which
         | it does look like they will - at least how it feels too me.
        
       | wyldfire wrote:
       | > PCIe board
       | 
       | That shows up on the roadmap. Does that mean it's only available
       | as an add-in card?
        
       | floatboth wrote:
       | > hybrid memory subsystem comprising four HBM2E memory stacks as
       | well as four or six regular DDR5 memory channels
       | 
       | YES! That's what I wanted to see happen.. I'm surprised AMD
       | wasn't first to do this, considering their history with HBM GPUs.
        
         | dragontamer wrote:
         | Hybrid memory systems are famously difficult to work with.
         | 
         | See XBox 360 eDRAM, Xeon Phi (DDR4 + HMC version), among
         | others. Its a computer architecture that keeps showing up every
         | few years... programmers get frustrated with the split-memory
         | architecture. So its rare for such a system to ever become
         | popular.
         | 
         | ----------
         | 
         | HBM RAM doesn't have any better latency characteristics than
         | DDR4. Traversing a linked-list in HBM will take the same amount
         | of time (maybe even a bit longer) than DDR4. As such, its non-
         | obvious how to optimize the split-memory operations.
         | 
         | NUMA-style mallocs / frees (malloc to a particular memory
         | location) don't really match the performance characteristics
         | either. Its not that one or the other RAM has better latency...
         | its that one RAM has more BANDWIDTH than the other. NUMA-style
         | is already more complicated than most programmers are willing
         | to work with, and yet its still not enough to capture the
         | performance attributes of HBM vs DDR4.
        
         | ChuckNorris89 wrote:
         | AMD was almost sinking till a few years ago, so throwing the
         | little money they had in expensive pipe dreams like this would
         | have been their end.
         | 
         | Best they stuck to their strengths like Ryzen CPUs and Radeon
         | GPUs and turned the ship around.
        
           | rbanffy wrote:
           | Processors designed for HPC, GPUs and generic server CPUs
           | have different evolutionary forces acting on them. We can be
           | sure AMD did at least some simulations on EPYC about how HBM
           | memory would impact performance on server workloads.
           | 
           | It all depends on the workload and demand. AMD can have much
           | larger volume with a part tailored for the space between HEDT
           | and server than with one tailored to HPC workloads.
           | 
           | I would _love_ to misuse one of these as my personal
           | workstation (just I would have loved to use a Xeon Phi), but
           | not all my purchasing decisions are strictly rational.
        
       | dekken_ wrote:
       | > September 8, 2020
        
         | rbanffy wrote:
         | I wonder if the link could change to
         | https://www.tomshardware.com/news/sipearl-rhea-n6-open-silic...
        
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       (page generated 2021-02-25 23:03 UTC)