Factors affecting decryption speed: SSD, CPU and RAM

[etcetera]

I got an identical version of VeraCrypt installed on 3 differently configured machines (hardware-wise). The OS is identical in all 3 cases, identically configured (all clones).

1. i7-6820hq with 32GB of RAM and Samsung 2TB 980Pro SSD
2. i7-10750H with 32GB of RAM and Samsung 2TB 970 Pro
3. i7-7820HQ with 16GB of RAM and Samsung 2TB 980 Pro

980 and 970 Pro are fairly new and close to latest-greatest but have been superseded by Samsung 990 Pro M.2 SSD with the Pascal controller. The speed difference is around 7000Mb/sec versus 9000mb/sec IIRC but in a lab environment, in real life you can't feel it.

The main system partition has been encrypted, it won't boot without decryption. I roughly timed decryption times. The first place goes to (2) i7-10750H and 3rd to i7-7820hq with i7-6820 essentially not much faster at 2nd place. The (2) choice is noticeably faster, I didn't time it precisely just yet but seemed to add just 20 seconds to decryption versus the other ones adding a full minute to 1.5 min to decryption. I will determine precise figures.

Seems like CPU speed is the main factor in decryption speed, contrary to my expectation of SSD speed being the main factor. I will re-run the tests once I add 32GB to (3) and see how it performs.

 

[KGIII]

Seems like CPU speed is the main factor in decryption speed,

That makes sense to me as that's where decryption is done. I'd guess that it happens faster than drive read speeds with a modern CPU.

You'll also only need as much RAM as needs to be held by the system and by data being added to it.

Or so I'd expect...