As Choidebu wrote, the 8-pin EPS is for CPUs. ATX12VO is a motherboard/PSU specification and doesn't deal with CPUs. If we want lower CPU draw, that's an Intel/AMD issue. Most motherboards stay with the 8-pin and will continue to because today the mainstream CPU sockets must 10C/20T CPUs (a net win, IMO).
Interestingly, while 3.3V and 5V are still required, mITX will be the biggest beneficiary because of only one PCIe slot: by the PCIe specification, each PCIe slot must supply 3A of 3.3V (9.9 W). So, an average ATX motherboard with ~5 slots will
still need to supply 49.5 watts of 3.3V under the new ATX12VO. mITX gets away with just 9.9 W!
Likewise, Anandtech is quoting the upper bound of the 10-pin connector; it actually ranges 216 W (6A) to 288 W (8A). So, where does all the power go? The motherboard's internal consumption is relatively very low (i.e,.
the Z490 chipset die has a tiny 6 W TDP); it's the
external device power requirements that make a ~200 W "quota" disappear pretty quickly.
- all PCIe slots (66 W from 12V & 9.5 W from 3.3V)
- all the rear IO logic & power output (e.g., each USB 3.0 port requires a minimum 4.5 W)
- all the fans (e.g., each fan header is 12 W to 24 W)
- nominally one to two SATA devices (e.g., I estimate 5 to 10 W is reserved per SATA port)
A typical mITX motherboard with two SATA ports (7.5 W avg), six USB 3.0 ports internally and externally (4.5 W), one PCIe slot (75 W), and two fan headers (15 W avg) = a standard 10-pin ATX12VO mini-ITX needs to
reserve 147 watts minimum just for external devices you might connect. CPUs will need much more.
Add in M.2 slots (5 to 10 W), AIO-pump fan headers (18 to 24 W), any Thunderbolt 3 ports (15 W minimum), an RGB LED header (15 W to 36 W), etc. = the 10-pin is as small as they can go. FWIW, any good motherboard manual will spell out its power output reservations, i.e., see
this ASRock Z390 motherboard.
Overall, ATX12VO is a major positive change, relative to the snail's pace of ATX development over the past 25 years (ATX was introduced in 1995).