RAM empties itself even without safe erasure (#8156)

wiki/src/doc/advanced_topics/cold_boot_attacks.mdwn

@@ -34,5 +34,7 @@ Tails is running* can recover data from RAM as well. To avoid that,
 learn the different methods to [[shutdown
 Tails|doc/first_steps/shutdown]] rapidly.
 
-As far as we know, cold boot attacks are not a common procedure for data
-recovery, but it might still be good to be prepared.
+As far as we know, cold boot attacks are not a common procedure for
+data recovery, but it might still be good to be prepared. If no cold
+boot attack happens directly after shutdown, the RAM empties itself in
+minutes, and all data disappears.

wiki/src/support/known_issues.mdwn

@@ -198,6 +198,10 @@ Tails does not consistently [[!tails_todo
 more_efficient_memory_wipe desc="erase all system memory as it
 should"]].
 
+If no [[cold boot attack|doc/advanced_topics/cold_boot_attacks]]
+happens directly after shutdown, the RAM empties itself in minutes,
+and all data disappears.
+
 After using Tails Installer, the "emergency shutdown" doesn't work
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