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 %).

If the CPU is nearly idle, this is a good sign that whatever you're doing is IO-limited.

It's not clear from your question, but I think you're doing in-place encryption (converting a hard drive with data on it into an encrypted hard drive, preserving the data). The safe way to do this (with no chance of data loss in the event of a crash or power failure) is to read the unencrypted data, encrypt it, write the encrypted data to a temporary location, then write the encrypted data back over the unencrypted version. This ensures that there's always at least one complete copy of the data, but is very slow, requiring writing to a number of different locations on the disk for each block of data that's converted.

This may be an old question (asked in 2015, when I'm writing in 2019) but it's a top result in Google so my experience may be useful to any later reader. I installed VeraCrypt on a brand new, top-of-the-line AMD desktop that I built myself. Ryzen 7 2700X CPU, 16 GB DDR4 RAM, and a properly fast 512GB m.2 hard drive (can't remember exact speed ratings, but it's somewhere around 6Gb/s, proper m.2 speed), and a Nvidia 1060 GPU. The only installed programs are Windows 10 Pro and it's updates, Chrome, and the most recent version of VeraCrypt itself. I told VeraCrypt to encrypt the entire drive, as it's all a single partition.

VeraCrypt has been running for 1 hour and is at 40%, and it estimates it will need another 75 minutes to complete. It had initially estimated 20 minutes to encrypt the entire drive, but that estimate steadily increased. Total CPU usage is around 2%, and the breakdown actually shows VeraCrypt using 0.0%, whereas Task Manager at least uses 0.5%.

There are some assorted accounts of very slow write performance on SSDs on VeraCrypt's forums; I've only skimmed those threads. If it is also this slow when saving data to storage, I'll remove VeraCrypt and use only Windows file encryption, which I know is less secure but at least is usable.