diff --git a/borg/archive.py b/borg/archive.py
index a2cc59b99..3eccbbeef 100644
--- a/borg/archive.py
+++ b/borg/archive.py
@@ -494,6 +494,7 @@ class Archive:
 
     @staticmethod
     def list_archives(repository, key, manifest, cache=None):
+        # expensive! see also Manifest.list_archive_infos.
         for name, info in manifest.archives.items():
             yield Archive(repository, key, manifest, name, cache=cache)
 
diff --git a/borg/archiver.py b/borg/archiver.py
index 79bf65f03..4b13e47fd 100644
--- a/borg/archiver.py
+++ b/borg/archiver.py
@@ -284,8 +284,8 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
                 stats.print_('Deleted data:', cache)
         else:
             print("You requested to completely DELETE the repository *including* all archives it contains:")
-            for archive in sorted(Archive.list_archives(repository, key, manifest), key=attrgetter('ts')):
-                print(format_archive(archive))
+            for archive_info in manifest.list_archive_infos(sort_by='ts'):
+                print(format_archive(archive_info))
             print("""Type "YES" if you understand this and want to continue.\n""")
             if input('Do you want to continue? ') == 'YES':
                 repository.destroy()
@@ -354,8 +354,8 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
                     item[b'group'] or item[b'gid'], size, format_time(mtime),
                     remove_surrogates(item[b'path']), extra))
         else:
-            for archive in sorted(Archive.list_archives(repository, key, manifest), key=attrgetter('ts')):
-                print(format_archive(archive))
+            for archive_info in manifest.list_archive_infos(sort_by='ts'):
+                print(format_archive(archive_info))
         return self.exit_code
 
     def do_info(self, args):
@@ -380,8 +380,7 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
         repository = self.open_repository(args.repository, exclusive=True)
         manifest, key = Manifest.load(repository)
         cache = Cache(repository, key, manifest, do_files=args.cache_files)
-        archives = list(sorted(Archive.list_archives(repository, key, manifest, cache),
-                               key=attrgetter('ts'), reverse=True))
+        archives = manifest.list_archive_infos(sort_by='ts', reverse=True)  # just a ArchiveInfo list
         if args.hourly + args.daily + args.weekly + args.monthly + args.yearly == 0 and args.within is None:
             self.print_error('At least one of the "within", "hourly", "daily", "weekly", "monthly" or "yearly" '
                              'settings must be specified')
@@ -412,7 +411,7 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
                 self.print_verbose('Would prune:     %s' % format_archive(archive))
             else:
                 self.print_verbose('Pruning archive: %s' % format_archive(archive))
-                archive.delete(stats)
+                Archive(repository, key, manifest, archive.name, cache).delete(stats)
         if to_delete and not args.dry_run:
             manifest.write()
             repository.commit()
diff --git a/borg/helpers.py b/borg/helpers.py
index f96c1bf52..e97c88bf2 100644
--- a/borg/helpers.py
+++ b/borg/helpers.py
@@ -1,5 +1,6 @@
 import argparse
 import binascii
+from collections import namedtuple
 import grp
 import msgpack
 import os
@@ -119,6 +120,18 @@ class Manifest:
         self.id = self.key.id_hash(data)
         self.repository.put(self.MANIFEST_ID, self.key.encrypt(data))
 
+    def list_archive_infos(self, sort_by=None, reverse=False):
+        # inexpensive Archive.list_archives replacement if we just need .name, .id, .ts
+        ArchiveInfo = namedtuple('ArchiveInfo', 'name id ts')
+        archives = []
+        for name, values in self.archives.items():
+            ts = parse_timestamp(values[b'time'].decode('utf-8'))
+            id = values[b'id']
+            archives.append(ArchiveInfo(name=name, id=id, ts=ts))
+        if sort_by is not None:
+            archives = sorted(archives, key=attrgetter(sort_by), reverse=reverse)
+        return archives
+
 
 def prune_within(archives, within):
     multiplier = {'H': 1, 'd': 24, 'w': 24*7, 'm': 24*31, 'y': 24*365}