In addition to Optane M10 with M.2 2280 form factor, later Optane models (e.g. 900P that could be found inside Taiko Audio SGM Extreme) have even better latency and I pretty much posted everything below (only a limited number of images could be posted on this forum even if they're wrapped inside "spoiler" tags) with tons of benchmarking test results
https://www.my-hiend...4786#post244786
Here are the most interesting ones, 900P seemed to be performing "quite a bit" better when compared to what 800P and M10 could achieve
https://www.anandtec...ing-refreshed/4
https://www.anandtec...ing-refreshed/5
P4800X totally and utterly DESTROYED everything else (with NAND flash memory) in terms of latency, and then even the form factor seemed to make a difference as multiple audiophiles in Taiwan mentioned in the very first link
https://audiophilest...comment-1088701
The P4800X sounds better than the 900P! And the PCIe version sounds better than the M.2 version (P4801X).
I can only imagine what an externally powered PCIe P4800X with an upgraded OCXO clock could do!
https://www.anandtec...sung-memblaze/6

However, 900P (as well as 905P) and P4800X are only available in 3 form factors
Let's say we really do wanna power (without any modifications) Optane externally, most likely U.2 form factor should be an ideal choice while it's also the most affordable one.
By far the cheapest option should be this one while some reviewers already confirmed that's compatible with both 900P and 905P
https://www.amazon.c...d/dp/B01LZEYFD1

Similar ones from US cost much more and not sure if they're any better in terms of the SQ department, though we've gotta get the ones designed for U.2 but NOT for U.3 Gen-Z
https://www.microsat...o-u-3-gen-z-aic
https://www.eproduct...o-u-3-gen-z-aic
https://www.microsat...ssd-adapter-aic
https://www.eproduct...ssd-adapter-aic
https://www.microsat...r-sff-1102-nvme
This one costs a whopping 100 bucks and somehow it might be the only choice for M.2 slots
http://www.hwtools.n...dapter/M2F.html
Everything else will involve a cable of some sort rather than PCB traces, therefore it should be a good idea to avoid those options.
We should have plenty of Thunderbolt options for all three M.2 / PCIe / U.2 form factors but almost all of them would cost an arm and a leg to begin with.
OTOH, not sure if these USB-C options were bootable or not?
https://www.aliexpre...3466999645.html
https://www.amazon.c...e/dp/B09DKLM82S
https://www.aliexpre...0034657616.html
https://www.delock.c...3/merkmale.html
http://www.linkreal....s/LRNVC362.html
https://www.icydock....oods.php?id=363
https://www.amazon.c...r/dp/B08S5L22WB
We're getting only 16 CPU-direct PCIe lanes from an i7-6700K while under most circumstances they're connected to the one and only PCIe x16 slot, therefore internethandle should be connecting 16GB Optane M10 to the only USB-C port of his motherboard via H170 chipset
https://ark.intel.co...o-4-20-ghz.html
Of course the latency might not be ideal but having the chipset modified with TCXO should be fine, though going through JCAT USB Card FEMTO would provide even better results since it should be connected to that one and only PCIe x16 slot with CPU-direct lanes.
That's why we'll have better luck with one of those Xeon Scalable (or 12th Gen Alder Lake with 8 + 8 + 4 = 20 CPU-direct PCIe lanes) motherboards, multiple PCIe slots are available with CPU-direct lanes and therefore even Optane could take advantage of those low-latency slots. Not to mention the fact that we might consider copying part of our music library to Optane since the size of 900P is starting at 280GB. Right now 280GB ones with U.2 form factor only cost around 850 RMB (roughly $135) a piece in China, as usual it's gonna cost more than that anywhere else.