Ho installato l'SSD e ci ho trasferito l'intero OS (così non ho perso alcun dato)
Questo è il systemd-analyze con l'HD:
11s 282ms 344us NetworkManager.service
5s 828ms 405us bluetooth.service
5s 513ms 380us hwclock.service
5s 244ms 819us systemd-logind.service
5s 69ms 260us colord.service
4s 821ms 934us polkit.service
3s 145ms 959us lightdm.service
2s 76ms 627us systemd-user-sessions.service
1s 562ms 300us smbd.service
1s 189ms 711us systemd-vconsole-setup.service
1s 54ms 183us dev-mqueue.mount
985ms 818us systemd-binfmt.service
897ms 632us crond.service
861ms 563us dev-hugepages.mount
800ms 565us sys-kernel-debug.mount
796ms 289us systemd-modules-load.service
773ms 59us systemd-remount-fs.service
730ms 10us rc-local.service
694ms 884us proc-sys-fs-binfmt_misc.mount
651ms 761us systemd-tmpfiles-setup.service
615ms 793us systemd-udev-trigger.service
576ms 367us systemd-udevd.service
535ms 406us systemd-fsck@dev-disk-by\x2duuid-e56ea3f1\x2dff62\x2d4dd2\x2d9108\x2d40e45e7fcebf.service
495ms 609us wpa_supplicant.service
178ms 905us accounts-daemon.service
177ms 567us tmp.mount
151ms 955us systemd-sysctl.service
72ms 101us plymouth-start.service
65ms 819us upower.service
52ms 941us home.mount
39ms 541us systemd-journal-flush.service
38ms 7us udisks.service
37ms 809us systemd-random-seed-load.service
35ms 253us rtkit-daemon.service
24ms 731us sys-kernel-config.mount
12ms 987us plymouth-read-write.service
12ms 316us plymouth-quit.service
4ms 923us plymouth-quit-wait.service
2ms 104us sys-fs-fuse-connections.mount
Startup finished in 4s 883ms 996us (kernel) + 20s 153ms 951us (userspace) = 25s 37ms 947us
E con l'SSD:
3s 786ms 714us NetworkManager.service
1s 298ms 394us colord.service
1s 274ms 859us polkit.service
921ms 997us systemd-journal-flush.service
783ms 118us plymouth-start.service
577ms 154us bluetooth.service
473ms 473us systemd-logind.service
442ms 86us hwclock.service
319ms 981us rc-local.service
319ms 893us systemd-binfmt.service
200ms 534us crond.service
194ms 822us systemd-udev-trigger.service
149ms 930us systemd-vconsole-setup.service
144ms 268us dev-mqueue.mount
123ms 566us sys-kernel-debug.mount
114ms 77us systemd-udevd.service
107ms 381us systemd-sysctl.service
100ms 362us systemd-random-seed-load.service
99ms 902us systemd-modules-load.service
99ms 900us systemd-tmpfiles-setup.service
93ms 934us systemd-fsck@dev-disk-by\x2duuid-5d68e8e7\x2d6468\x2d4afd\x2d82c8\x2dd76dc3f2e231.service
93ms 749us dev-hugepages.mount
83ms 132us smbd.service
74ms 979us tmp.mount
71ms 104us home.mount
68ms 305us lightdm.service
67ms 181us sys-kernel-config.mount
67ms 124us plymouth-read-write.service
53ms 365us systemd-remount-fs.service
52ms 604us accounts-daemon.service
45ms 388us proc-sys-fs-binfmt_misc.mount
44ms 711us udisks.service
43ms 829us plymouth-quit.service
26ms 599us systemd-user-sessions.service
18ms 773us wpa_supplicant.service
16ms 430us plymouth-quit-wait.service
13ms 14us upower.service
8ms 224us rtkit-daemon.service
Startup finished in 2s 864ms 855us (kernel) + 4s 997ms 544us (userspace) = 7s 862ms 399us
Praticamente, ora ci mette un terzo ad avviarsi

EDIT: ho corretto i risultati perché systemd si era "inceppato" nell'avvio precedente