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Comment by sufiyan | Hacker News Reader

If so, why dont they increase refresh rates given that most of the memory (>95%) can do refreshes at numbers of over 3x existing refresh rates. This could potentially increase the energy savings and also potentially make the system faster because of lesser waiting time during Refresh and Row Activation.

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Faster refresh will mitigate leakage, so you can run your DRAM hotter, but I don't see how that helps energy savings. Refresh means current flows out of the cell, through the sense amplifier, and then current flows back in, through the word driver. More refresh means more current. More current flow, more power consumption. This does not seem to argue for energy savings.

I meant reduce the refresh rate. My bad. Should have proof read what I typed. Essentially, what I meant was that many dram chips needn't be refreshed as often as they are now.

why dont they increase refresh rates

Apple did exactly this to the EFI of some machines, to mitigate Rowhammer[1]:

   Description: A disturbance error, also known as
   Rowhammer, exists with some DDR3 RAM that could
   have led to memory corruption. This issue was
   mitigated by increasing memory refresh rates.

[1] https://support.apple.com/en-us/HT204934

I read an article that explained that DRAM cannot be read or written to during a refresh cycle, so if you triple the frequency of the refresh, you'll substantially harm the performance and throughput of the RAM.

I think they already did. The 2x refresh option has existed since DDR2, and was originally designed for very high temperatures BTW.

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