Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > alt.comp.os.windows-11 > #18493

Re: memory usage vs fan usage

Show all headers | View raw

On 2025-04-18 18:13, VanguardLH wrote:
> "Carlos E.R." <robin_listas@es.invalid> wrote:
> 
>> The operating system would know, and decide not to use part of the
>> memory. Switch it off, no contents to worry about losing. But I suspect
>> the power saved would be minimal.
> 
> I have 64 GB of RAM.  That would be a hell of a lot of writes to
> remember (64 GB) to know if some memory had been written in the past.
> With my 64 GB of RAM, another 64 GB of RAM or cache on very slow disk
> would be need to track which addresses had been written in the RAM.  Or,
> alternatively, I could only use 32 GB of my RAM, because the other 32 GB
> was used for tracking past writes.
> 
> This history cache to record which addresses were accessed wouldn't need
> to be as big as the main RAM that stores the data, or maybe a bit
> mapping could be used to equate an address in RAM to a bit in history
> RAM, but the history would have to record all writes however long the
> computer had been powered up, including sleep modes.  More RAM would be
> needed to track writes to main RAM.  You certainly wouldn't use a
> history cache on a drive.

No, if the feature existed it would switch on/off large blocks of 
memory, probably entire modules or chips.


> 
>>> Okay, but it takes a moment to come out of sleep mode, and that would
>>> be highly impactful to the performance and responsiveness of the OS
>>> and apps if the computer were constantly diving into deep sleep to
>>> immediately come out of it.
>>
>> Not important, because switching a memory module on would happen when
>> loading more software, or when some application demands a lot more
>> memory. This would be a rare event.
> 
> No, the moment any process needed a single byte from a memory module
> would require the memory module to be instantly turned on from sleep.

No. It would happen only when a program wants to assign, for instance, a 
block of 100 MB of memory, and the operating system decides whether to 
use swap or activate more ram.

Accessing a byte? No, that byte is already assigned and live.

A ram module can not be switched off while any code holds addresses on it.

> That includes the OS along with any services and backgrounded programs.
> Yes, executables have an image loaded into memory when they get loaded,
> but memory is also accessed by running processes.  ALL processes would
> have to get suspended to prevent any memory access during sleep.  Well,
> that's when sleeping, and neither you nor the computer can do anything,
> so it appears all memory modules can go into a partial reduced power
> mode, but require constant refreshing and voltage can never be reduced.
> The constant refreshing to retain content in memory and required voltage
> means the memory module doesn't sleep, it just has a lower duty cycle to
> reduce its power consumption, but then DRAM doesn't consume much power.
> 
>> It might be interesting for phones and other battery operated devices.
>>
>> You make me wonder: mobile phones use dynamic ram, or static ram?
>>
>> I think calculators use static.
> 
> Static RAM holds its data as long as it has power.  Does not require
> refreshing versus dynamic RAM where data decays in seconds and needs
> constant refreshing.  SRAM is faster than DRAM, but not as dense as
> DRAM.  SRAM is used in cell phones and wearables, and as a cache for the
> CPU registers (i.e., microprocessors have SRAM), but then nowhere near
> as much memory is needed as for main system memory where programs are
> loaded and data is stored.
> 
> There is also NVSRAM where batteries are impractical to preserve data,
> like in medical equipment where data loss is intolerable from a power
> loss.  I've never looked into PSRAM (Pseudostatic SRAM) which puts the
> refresh logic inside the memory module.
> 
> I don't see SRAM sold at Newegg.  I've never had a desktop build nor
> pried into a laptop that had sockets for SRAM, just for DRAM.  I did
> find SRAM sold online, like at:
> 
> https://www.mouser.com/c/semiconductors/memory-ics/sram/
> 
> 4 GB SRAM (134,217,728 x 32) was the largest they list.  They didn't
> show pricing since it was out of stock.  It is a BGA package, so has to
> get soldered which reflects its specialty use, not slid into a socket.
> 
> I suspect Paul, based on the technical detail of his posts, has dug more
> into where SRAM might get used.


-- 
Cheers, Carlos.

Back to alt.comp.os.windows-11 | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-17 15:16 +0100
  Re: memory usage vs fan usage Paul <nospam@needed.invalid> - 2025-04-17 12:09 -0400
    Re: memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-17 19:57 +0100
      Re: memory usage vs fan usage Paul <nospam@needed.invalid> - 2025-04-18 03:15 -0400
  Re: memory usage vs fan usage VanguardLH <V@nguard.LH> - 2025-04-17 11:59 -0500
    Re: memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-17 19:40 +0100
      Re: memory usage vs fan usage Frank Slootweg <this@ddress.is.invalid> - 2025-04-19 12:04 +0000
        Re: memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-19 13:36 +0100
          Re: memory usage vs fan usage Paul <nospam@needed.invalid> - 2025-04-19 09:25 -0400
          Re: memory usage vs fan usage Frank Slootweg <this@ddress.is.invalid> - 2025-04-19 14:54 +0000
            Re: memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-19 16:16 +0100
            Re: memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-24 08:17 +0100
              Re: memory usage vs fan usage VanguardLH <V@nguard.LH> - 2025-04-24 05:14 -0500
                Re: memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-24 11:30 +0100
                Re: memory usage vs fan usage Paul <nospam@needed.invalid> - 2025-04-24 09:08 -0400
                Re: memory usage vs fan usage VanguardLH <V@nguard.LH> - 2025-04-24 20:59 -0500
                Re: memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-25 07:40 +0100
                Re: memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-25 19:13 +0100
                Re: memory usage vs fan usage VanguardLH <V@nguard.LH> - 2025-04-25 22:29 -0500
                Re: memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-26 10:31 +0100
                Re: memory usage vs fan usage VanguardLH <V@nguard.LH> - 2025-04-26 15:05 -0500
        Re: memory usage vs fan usage "Carlos E.R." <robin_listas@es.invalid> - 2025-04-19 14:36 +0200
          Re: memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-19 13:56 +0100
          Re: memory usage vs fan usage Paul <nospam@needed.invalid> - 2025-04-19 09:28 -0400
  Re: memory usage vs fan usage VanguardLH <V@nguard.LH> - 2025-04-17 15:07 -0500
    Re: memory usage vs fan usage "Carlos E.R." <robin_listas@es.invalid> - 2025-04-17 22:25 +0200
      Re: memory usage vs fan usage VanguardLH <V@nguard.LH> - 2025-04-17 19:30 -0500
        Re: memory usage vs fan usage "Carlos E.R." <robin_listas@es.invalid> - 2025-04-18 14:09 +0200
          Re: memory usage vs fan usage VanguardLH <V@nguard.LH> - 2025-04-18 11:13 -0500
            Re: memory usage vs fan usage "Carlos E.R." <robin_listas@es.invalid> - 2025-04-18 21:33 +0200
    Re: memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-17 22:12 +0100
      Re: memory usage vs fan usage VanguardLH <V@nguard.LH> - 2025-04-17 20:07 -0500
      Re: memory usage vs fan usage Paul <nospam@needed.invalid> - 2025-04-18 05:24 -0400
        Re: memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-18 12:08 +0100
          Re: memory usage vs fan usage Frank Slootweg <this@ddress.is.invalid> - 2025-04-18 18:09 +0000
            Re: memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-18 19:36 +0100
  Re: memory usage vs fan usage "Carlos E.R." <robin_listas@es.invalid> - 2025-04-17 22:29 +0200
    Re: memory usage vs fan usage Andy Burns <usenet@andyburns.uk> - 2025-04-17 22:17 +0100
      Re: memory usage vs fan usage "Carlos E.R." <robin_listas@es.invalid> - 2025-04-18 02:19 +0200
      Re: memory usage vs fan usage Paul <nospam@needed.invalid> - 2025-04-18 05:52 -0400

csiph-web