Im using a E5-2699 v4 VM with 8 cores as well as a GTX 1080 not Direct Allocated (RemoteFX) technically on a Server 2016 Host.
Able to transcode multiple 4k/1080i/720p streams. I rip all media (DVD, Blu Ray, YouTube, etc.) and use a DC S3510 Raid6 array for the media. In my Plex server settings...
Sure, SSD is improvement over HDD/SAS. The traffic is absolutely going to disk. (1) of the culprits are public speedtest server. WAN to LAN, no way around it. I can limit (who) gets to speedtest but... thats another thread :)
NVMe on 10Gb+ yield good results. A single SFP+ or bonding SFP+...
Specifically, Raid 6 DC S3510 Server 2016 Host, DC P3608 VM Storage.
Nothing specifically set up for cache on PfSense (no squid, etc.) other than Intel built-in features of the DC drives (which need run RSTe software to work).
NVMe is the way to go if I had to nail it to a single sentence.
In my case, the P3608's are substantially faster than non-PCIe disk's (all of them) so I use them for PfSense. Using other drives (SATA/SAS) would slow things down considerably. The cache is the DC P3608's.
Sory was for the OP, If I used my DC S3510 SSD'sthat traffic would eat the drives in short time. Versus the DC P3608's I use which have higher resiliency before failure.
Personally I wouldn't use consumer drives for PfSense.
I use 8GB DDR4 and 8 Cores (E5-2699 V4) on a Virtual Machine for PfSense for 10Gb connections bonded to 20Gb.
I see up to 75% CPU loads and 30-50% mem loads.
Although I am using IDS (Snort, VPN, Multi-WAN)
Have (x2) Intel E5-4648 12 Core - 24 Thread CPU's. Very lightly used, have warranty. These are Retail Chips.
No Coolers/Heatsinks provided.
Asking $500 each.
More Info: Intel® Xeon® Processor E5-4648 v3 (30M Cache, 1.70 GHz) Product Specifications
These Chips work in all boards I have...
Generally speaking the speed of SMB share's over a network is disk dependent more than your NIC's. Depending on the disk configuration, you would see slow copy speeds. Copy paste I assume, I think cut/paste is better for a quick speed idea imo.