[HN Gopher] The Death of SRAM?
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       The Death of SRAM?
        
       Author : _hypx
       Score  : 37 points
       Date   : 2022-12-14 20:55 UTC (2 hours ago)
        
 (HTM) web link (fuse.wikichip.org)
 (TXT) w3m dump (fuse.wikichip.org)
        
       | nordsieck wrote:
       | > So where do we go from here? The reality is that currently, the
       | only viable alternative to SRAM is simply more SRAM, and
       | therefore we expect to see SRAM directly consuming more area.
       | 
       | Betteridge's law strikes again.
        
         | richardjam73 wrote:
         | It's more of an extinction than a death. If SRAM can't shrink
         | it will eventually be replaced by other technologies that can.
        
           | EarlKing wrote:
           | Not exactly. SRAM will be replaced by other technologies that
           | can if and only if there is a commensurate increase in speed
           | (since that's the whole point of using SRAM over DRAM).
        
             | _hypx wrote:
             | There's already talk of STT-MRAM or SOT-MRAM replacing
             | SRAM. They offer similar performance while also being non-
             | volatile. If SRAM scaling ends, this becomes a much more
             | promising technology.
             | 
             | https://semiengineering.com/sot-mram-to-challenge-sram/
        
       | userbinator wrote:
       | _such as higher density at lower read /write specifications, non-
       | volatility capabilities, lower read-write cycle capabilities_
       | 
       | Also known as NAND flash, i.e. the chips that actually wear out.
       | Another example of planned obsolescence creeping in to what used
       | to be effectively unlimited lifespan for "solid state"
       | electronics?
        
         | to11mtm wrote:
         | There's different options for different things.
         | 
         | You have:
         | 
         | - EEPROM for low/medium frequency of update, small size,
         | persistence
         | 
         | - NAND flash for low/medium frequency of update, semi-arbitrary
         | size, persistence
         | 
         | - eDRAM variants (Mosys '1T SRAM' comes to mind, which is still
         | DRAM but has more dedicated Row/Column circuitry vs SDRAM's
         | RAS-CAS timing shenanigans) for frequent update, volatile or
         | maybe battery backed storage, non-persistent
         | 
         | Which... we -kinda- see in some layers already, as eDRAM has
         | gone from 'fancy server procs and halo mobile chips' to a
         | -little- more mainstream.
        
       | ajross wrote:
       | Wasn't this already sorta common knowledge? Almost the tricks in
       | recent process generations to increase density have been
       | vertical. FinFETs et. al. work by stretching the transitor
       | upwards to increase gate area, so it drives harder and you need
       | fewer of them to implement the same logic. But the actual pitches
       | of the gate and fins haven't been changing nearly as fast, so the
       | smallest circuits aren't seeing much benefit.
       | 
       | A SRAM cell is 6-8 transistors all connected internally with only
       | a read and data line coming out (well, and the power rails).
       | That's already horizontally packed, making the transistors
       | beefier won't help anything.
        
         | aidenn0 wrote:
         | Do recent generations help at all with multiply ported SRAM?
        
       | mjevans wrote:
       | Not the death, but AMD's chiplets at different process nodes is
       | the approach of the future. One of the slides I remember from an
       | AMD presentation in recent Gamers Nexus videos showed curves for
       | cache, logic, and a third curve across process nodes.
       | 
       | SRAM has desirable properties; simplicity, self sustaining state,
       | latency.
       | 
       | The flattening curves follow the approach to the physical limits
       | of doped silicon. It'll be interesting to see if another electron
       | based but different semiconductor or another method of computing
       | entirely (maybe photonics or some other range of the EM
       | spectrum?) continues the rise in density or if we instead focus
       | more on optimizing hardware and software.
        
         | arcticbull wrote:
         | Yeah, basically. The 3D-VCache approach reduces the need for
         | scaling by increasing the surface area available. It's not
         | quite as important to get the absolute smallest transistors if
         | you can use a larger process node, make the cache the same size
         | as the entire rest of the die, then stick it on top.
         | 
         | You're no longer competing for space on the same die as the
         | functional units.
        
       | Gualdrapo wrote:
       | Oh. _That_ SRAM. For a moment I imagined Bauke Mollema was
       | cheering up reading this[0].
       | 
       | [0] https://www.youtube.com/watch?v=Tsk3zAZyLaQ
        
         | davidw wrote:
         | Yeah... started thinking "uh oh, where am I going to get
         | replacement bits for my MTB?!"
        
         | turminal wrote:
         | Age restricted and wants me to sign in :(
        
           | LeifCarrotson wrote:
           | They're talking about the bicycle component vendor named
           | SRAM:
           | 
           | https://www.sram.com/en/sram/mountain
        
             | to11mtm wrote:
             | It's been forever since I've been deep into biking so I'm
             | afraid to click the link.
             | 
             | 9 speed was already almost too much for a 'casual-
             | enthusiast' [0].
             | 
             | But in general, Shimano or Campy is my preference for
             | drivetrain [1] and Avid/Shimano for brakes [2].
             | 
             | [0] - I've blown out 9 speed cassette in less than 1k miles
             | due to my riding style (skipping gears). NEVER had a
             | similar problem on the 8 speed cassettes or 5 speed
             | freewheels I would roll on.
             | 
             | [1] - Ok so I had a SRAM grip-shift break in a way it shot
             | plastic in my face which was a terrible first impression.
             | But also I've had 'issues' with a lot more SRAM vs Shimano
             | when building/maintaining bikes. And then there was the
             | Truvativ 3 speed road crank that could never get adjusted
             | right (FWIW, I got the same 'model' as a double for a
             | tandem and it was bliss... but that is my point about QC.)
             | Also, that mess that was 'power spline'. Tore that up
             | before in less than 500 miles.
             | 
             | [2] - In the day I was all about Speed-Dial 7s[3] for
             | levers and BB7s for brakes (Very adjustable, none of the
             | pains of fluid based disc brakes) and Shimano had a bad
             | habit of trying to make things proprietary (center-lock
             | disc hubs).
             | 
             | [3] - SD7s are the best retrofit-bike thing on the planet,
             | because they can make all sorts of old/new brake
             | combinations work with a consistent set of levers!
        
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