That's not the point of SFP for most of us at the moment.
There are three main points of entry for now:
1: Workstation is a server data service connector and 1GbE RJ-45 gets too easily saturated to push the data several GB/hour from this socket.
This is the most common situation people have with a media server loaded with tons of raws and video. This is how they do backups/editing
and it sucks.
Net speed gets frequently pinned 100% and latency is too high due to disk types and data sizes. General access and scrubbing are insufferable.
Basic 2x1GbE teaming or a 2.5GbE connection usually fixes it.
2: Workstation is connected to a NAS/DAS array and 2.5GbE somehow experiences a continuation of the above problems due to slow type of storage.
This is a less common problem as people in this situation typically opt for sata/m.2 SSDs over sata HDDs, so even non-RAID volumes should be fine.
The data sets used here are LARGE. Much larger than the photo/video editor situation in piecemeal.
Probably an animator/renderer or SQL DB admin doing wacky stuff with backup/migration or lots of networked Hyper-V jobs through one socket.
3. Network has a massive data chokepoint with the server on two disjunct networks for all media access between one or two local systems and the Internet.
This is a more common situation where the CPU, disk speed, data type and data size just don't matter because the network controller is too finnicky.
Consistent access to the server matters way more than anything else, so a
direct 2.5/10GbE connection is optioned to satisfy the problem.
That last one is pretty much where I'm at with millions of files, thousands of gigantic images, some iSCSI volumes and an ISP that randomly makes everything go poof.
All the basic 1GbE connections are routed through their shitty little XB3 unit and this is what prompted me to look at SFP in the first place.
The poof is extremely annoying
and dangerous to data when it happens. It may as well be an overheat+reboot because same result. The 10GbE SFP option solves it entirely.
My HP QLogic rebrand NC523SFP and SolarFlare SFN5122F averaged
~$20/each from auction and I used a cheap Cisco DAC to connect them. I would not opt for QLogic again as I had to rig the device with a fan just to exhaust an insane amount of heat produced from this card but other than that, it works great. You literally cannot lose.
That's what I did. So in terms of discount enterprise hardware, 10GbE is CHEAP CHEAP but has its own price. It's all PCI-E g2x8 era junk. If you're interested in this, great. Just use best discretion and maybe avoid QLogic if you're worried about heat. The passive heatsink on that thing is enough to cook lotto tickets, as in it will physically burn you if you do a shutdown and want to pull the card. It's an odd one out. Other stuff is built correctly.