At the moment of posting it's been 38 minutes since initiating a 16 hour header download, NB reports (4) under cache, is using 1.13GB (and rising) of memory, 7-11MB/s of disk and ranging between 5 and 14% of my cpu (I7-4790) FWIW disk access on the drive that the headers are stored can peak at 120MB+ (when I'm compressing headers for example)
After this processing finally finishes I will go back to 6.6X to see if it's any faster for the same selection of groups, but on the bright side, I can post again

Note: activated verbose logging and bounced the program (before going back to 6.6x) it started with a (3) in cache and is using the cpu and disk to presumably process the already downloaded headers as things propagate into the log I'll post here:
[14:22:55] DEBUG High Speed File Creation Mode: Disabled - "Run as Administrator" to Activate this mode
[14:22:55] HIGH PAR Pausing: Enabled
[14:22:55] HIGH Par2Repair - Multi-core 1.5
[14:22:55] HIGH MessageId Filter: Disabled
[14:22:55] HIGH FileType Version: 2.01
[14:41:28] DEBUG Checking Autodownload: alt.binaries.hdtv
[14:43:58] DEBUG Checking Autodownload: alt.binaries.hdtv
[14:48:57] DEBUG Checking Autodownload: alt.binaries.multimedia
(Note, I don't use autodownload....) sometime prior to 1504 (but after 1448) it finished as cache now shows (0) and the group list shows a combined total of 92798 New files under the main screen (before choosing to view the groups) so it *might* be down to so much spam being posted, but that sort of delay is still ghastly. Will try 6.6X when I grab more headers in 7 or 8 hours.