went ahead and did another fresh install ... problem solved!
i still don't know what the hell i did wrong last time, but i'll outline what i did and the changes made in case others run into the same issue.* = changes made from previous fresh install
1. made UEFI bootable win8 USB drive* (used same USB drive as last time, but was formatted in NTFS. used instructions here
2. put Intel SATA drivers (v18.104.22.1683) on USB drive for loading during install* (didn't do this last time)
3. disconnected all other HHDs except SSD that OS will go on & plugged in UEFI bootable USB drive
4. clear CMOS (button turns on machine automatically)* (didn't do this last time since all components were new and i didn't think i needed to)
5. went into UEFI:
-disabled ASMedia SATA controller* (left enabled last time)
-set native SATA controller to RAID* (default is AHCI so i'm now sure this was what it was set at last time)
-changed boot priority to UEFI USB drive* (USB drive was not listed as "UEFI" last time. picture
-saved settings and rebooted
6. went through windows 8 install procedure
7. deleted partition on SSD and reformatted* (noticed windows 4 partitions, 3 were small and reserved for windows and 1 were the OS would go. only 2 partitions were created last time)
8. loaded intel SATA drivers*
windows finished installing and booted straight into the start page. last time, it stalled at the windows logo screen, even the first time it booted. now i don't even see that screen - windows boots straight into the Start page. checked the Task Manager and the Last BIOS time is consistently 4.8 - 5.0 seconds!
i've since changed the intel SATA controller to AHCI b/c it showed and extra screen during POST in RAID. i've also installed all mobo drivers and enabled the ASMedia SATA controller in UEFI. and plugged in the other HHDs. i'm happy to say there's been no slow down in boot up time.
i still don't know what i did during the last install to cause such a delay in bootup. oh well ... i'm glad things are back to normal. thanks to all who tried to help!