Tacit,
Not much.
Recently, I opened a support case with AppleCare to investigate why my iMac (mid-2010) with 8 GB of RAM failed to connect automatically with Wi-Fi when it was awakened from sleep. I sent in a lot of logs, collected with Apple's Capture Data application, and they were forwarded to the engineers. In the meantime, it was suggested that I let the display and the hard drive sleep, but not the computer itself. One of the Apple support techs noted that the distance from my iMac to my Airport Extreme Base Station was 3 feet, so I connected the computer and the base station with a Hubbell cat6 ethernet cable, one so privileged that it has its own serial number. He gets the "I can see both the forest and the trees" award. Turning off Wi-Fi in the menubar does not make Wi-Fi unavailable for other devices, such as my iPod Touch, which informs me in real time of weather alerts and food and product recalls.
The Mac OS X 10.7.3 update was intended to solve the "failure to connect with Wi-Fi upon awakening from sleep" problem that some users of Mac OS X 10.7.2 had reported. In my case, the update itself resulted in a problem of which I had been unaware.
Here is part of my All Messages log. Note that the kernel is quite busy while I am asleep:
2/14/12 3:17:43.931 AM SubmitDiagInfo: Cleaning up expired diagnostic messages database at path: /var/log/DiagnosticMessages/2012.01.15.asl
2/14/12 4:28:42.000 AM kernel: (default pager): [KERNEL]: ps_allocate_cluster - send HI_WAT_ALERT
2/14/12 4:28:42.000 AM kernel: macx_swapon SUCCESS
2/14/12 4:45:30.000 AM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 4:45:30.000 AM kernel: macx_swapon SUCCESS
2/14/12 6:32:00.766 AM Mail: Using V2 Layout
2/14/12 6:32:10.000 AM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 6:32:10.000 AM kernel: macx_swapon SUCCESS
2/14/12 6:44:20.000 AM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 6:44:20.000 AM kernel: macx_swapon SUCCESS
2/14/12 7:01:33.000 AM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 7:01:33.000 AM kernel: macx_swapon SUCCESS
2/14/12 7:13:15.000 AM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 7:13:16.000 AM kernel: macx_swapon SUCCESS
2/14/12 7:54:19.000 AM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 7:54:21.000 AM kernel: (default pager): [KERNEL]: Switching ON Emergency paging segment
2/14/12 7:54:22.000 AM kernel: (default pager): [KERNEL]: ps_vstruct_transfer_from_segment - ABORTED
2/14/12 7:54:22.000 AM kernel: (default pager): [KERNEL]: Failed to recover emergency paging segment
2/14/12 7:54:22.000 AM kernel: macx_swapon SUCCESS
2/14/12 9:07:12.000 AM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 9:07:12.000 AM kernel: (default pager): [KERNEL]: ps_vstruct_transfer_from_segment - ABORTED
2/14/12 9:07:12.000 AM kernel: (default pager): [KERNEL]: Failed to recover emergency paging segment
2/14/12 9:07:12.000 AM kernel: macx_swapon SUCCESS
2/14/12 9:16:04.000 AM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 9:16:05.000 AM kernel: (default pager): [KERNEL]: ps_vstruct_transfer_from_segment - ABORTED
2/14/12 9:16:05.000 AM kernel: (default pager): [KERNEL]: Failed to recover emergency paging segment
2/14/12 9:16:05.000 AM kernel: macx_swapon SUCCESS
2/14/12 9:29:57.000 AM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 9:29:58.000 AM kernel: (default pager): [KERNEL]: ps_vstruct_transfer_from_segment - ABORTED
2/14/12 9:29:58.000 AM kernel: (default pager): [KERNEL]: Failed to recover emergency paging segment
2/14/12 9:29:58.000 AM kernel: macx_swapon SUCCESS
2/14/12 11:18:29.000 AM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 11:18:39.000 AM kernel: (default pager): [KERNEL]: ps_vstruct_transfer_from_segment - ABORTED
2/14/12 11:18:39.000 AM kernel: (default pager): [KERNEL]: Failed to recover emergency paging segment
2/14/12 11:18:39.000 AM kernel: macx_swapon SUCCESS
2/14/12 11:32:44.000 AM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 11:32:44.000 AM kernel: (default pager): [KERNEL]: ps_vstruct_transfer_from_segment - ABORTED
2/14/12 11:32:44.000 AM kernel: (default pager): [KERNEL]: Failed to recover emergency paging segment
2/14/12 11:32:44.000 AM kernel: macx_swapon SUCCESS
2/14/12 11:37:37.000 AM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 11:37:38.000 AM kernel: (default pager): [KERNEL]: ps_vstruct_transfer_from_segment - ABORTED
2/14/12 11:37:38.000 AM kernel: (default pager): [KERNEL]: Failed to recover emergency paging segment
2/14/12 11:37:38.000 AM kernel: macx_swapon SUCCESS
2/14/12 12:03:12.000 PM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 12:03:12.000 PM kernel: (default pager): [KERNEL]: ps_vstruct_transfer_from_segment - ABORTED
2/14/12 12:03:12.000 PM kernel: (default pager): [KERNEL]: Failed to recover emergency paging segment
2/14/12 12:03:12.000 PM kernel: macx_swapon SUCCESS
2/14/12 12:05:50.000 PM kernel: (default pager): [KERNEL]: default_pager_backing_store_monitor - send LO_WAT_ALERT
2/14/12 12:06:35.000 PM kernel: macx_swapoff SUCCESS
2/14/12 12:13:23.000 PM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 12:13:23.000 PM kernel: macx_swapon SUCCESS
2/14/12 1:17:53.319 PM xpchelper: for uid: 0 -- timeout while waiting on FSEvents flush; clearing cache.
2/14/12 1:41:23.000 PM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 1:41:32.000 PM kernel: macx_swapon SUCCESS
2/14/12 2:54:00.000 PM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 2:54:04.000 PM kernel: macx_swapon SUCCESS
2/14/12 3:18:11.000 PM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 3:18:12.000 PM kernel: macx_swapon SUCCESS
2/14/12 4:12:39.000 PM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 4:12:49.000 PM kernel: (default pager): [KERNEL]: Switching ON Emergency paging segment
2/14/12 4:13:00.000 PM kernel: (default pager): [KERNEL]: ps_vstruct_transfer_from_segment - ABORTED
2/14/12 4:13:00.000 PM kernel: (default pager): [KERNEL]: Failed to recover emergency paging segment
2/14/12 4:13:00.000 PM kernel: macx_swapon SUCCESS
2/14/12 4:26:17.000 PM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 4:26:18.000 PM kernel: (default pager): [KERNEL]: ps_vstruct_transfer_from_segment - ABORTED
2/14/12 4:26:18.000 PM kernel: (default pager): [KERNEL]: Failed to recover emergency paging segment
2/14/12 4:26:18.000 PM kernel: macx_swapon SUCCESS
2/14/12 4:50:59.000 PM kernel: (default pager): [KERNEL]: default_pager_backing_store_monitor - send LO_WAT_ALERT
2/14/12 4:52:06.000 PM kernel: macx_swapoff SUCCESS
2/14/12 5:27:43.000 PM kernel: (default pager): [KERNEL]: ps_select_segment - send HI_WAT_ALERT
2/14/12 5:27:43.000 PM kernel: macx_swapon SUCCESS
The most RAM-intensive applications I have are Aperture and Capture One Pro. When using both of them at once, I have seen at most eight swapfiles. Neither application was open during the nineteen swapfiles event.
