Total, initial, hard drive encryption speed with VeraCrypt

Context: I decided to encrypt a 2TB Internal Sata II hard drive I use for personal files (photo collections, tax prep PDFs, hosting a synced Dropbox folder, some non-HD video files, driver install backups, etc). The drive is nearly full of content at this point; and I store new files to another larger disk, as well as backup the 2TB to the larger drive.

I'm using the current VeraCrypt version (VeraCrypt 1.0f-2). And I used the standard Volume Creation Wizard for full drive/partition encryption, with no wipe (fast), and basic AES settings... just to keep thieves hands off my data (I'm not worried about the CIA/NSA).

System is Win7 64bit OS (run off a nice SSD), Quad Core 2.6ghz AMD Athlon II, 8GB 1333 DDR3 RAM, the hard drive being encrypted is a fairly old Western Digital formatted to NTFS (it ran fine prior to this process being started).

Questions 1 + 2: Why is this going to take nearly 4 whole days to complete (96h; I estimated 6mbps)? Is this normal?

I can't find anything online that estimates initial hard drive encryption speeds for any quantities of data on any types of hard drives. Everything says "it just depends on hardware." Which is no help, for even general comparison.

I've read that encryption takes place in the processor, and that it generally runs faster when there are more cores because VeraCrypt uses them in parallel. But my processor is basically at idle! With Firefox open (10 tabs), a file browser, and the encryption taking place I'm averaging around 7% utilization across the cores (it only spikes for a second if I open another tab or start another activity elsewhere).

And the RAM utilization is only at about 25% (normal for just the OS and Firefox).

Questions 3 + 4: Is it normal for a processor to appear at idle while completing the initial encryption of a large hard drive/partition? And, is there an option somewhere that can tell VeraCrypt to use whatever resources it wants to speed up the process?

Note: The majority of the 'speed' questions I've encountered online are regarding the initial mounting with VeraCrypt--which is slower than with TrueCrypt because of added security measure--or on the fly encryption/decryption speeds. The questions I've asked are not about those things, but instead specifically being asked to learn from those with experience what kind of speed they experienced during the initial encryption of whole data drives/partitions, not their mounting or on the fly encryption/decryption; as well as what kind of resource utilization is normal (Processor/RAM %).