I should start my own thread of inquiry, but I'll see if the interested parties here can offer some advice.
My sig Skylake has 16GB of TridentZ 3200 14-14-14. It was great: just pop them in, set the XMP profile in BIOS, and they tested out flawless with HCI Memtest 64.
This is -- for just about everything -- plenty of RAM. In fact -- after trial-testing Romex PrimoCache back in 2014, I've been using it ever since. And I've used some of the RAM for that -- as much as 4 to 6 GB leaving 10GB for everything else. The caching program caches to SSD as well as RAM. But I've begun to wonder what sort of performance I'll get by expanding the RAM allocated to the caching.
So for months, I've been conflicted about (a) getting another "identical" TridentZ kit, or (b) replacing this kit with a set of 2x16 = 32GB of 3200 14-14-14.
I contacted G.SKILL tech-support, and they're always good about getting back by e-mail -- great folks there.
"If I had an identical kit, will I be able to run them without flaw at XMP DDR4-3200 14-14-14?"
"We can't guarantee that. We match out 4x8=32GB kits to assure it. But we can't guarantee that running the two [identical] kits will make that possible."
"What about dropping the speed to DDR4-3000 and the same 14-14-14 timings?"
"We could work with that!" [Meaning -- they could support it for RMA or whatever purposes. G.SKILL has always been stellar for quick replacement of defective sticks.]
That's option "(a)". Option (a) will cost me $180+ at today's prices throwing in tax and shipping. Option (b) will cost me north of $324.
I consider that I have to test the whole enchilada, either with option (b) or option (a), but I'm sure I can get it done running HCI's program in Windows. [I used to prefer using the self-booting CD version of the test program -- stupid, I know. . . ]
WHAT SHOULD I DO? [and why should I do it?]
With a system like this, there is no hurry at this point except for the topic of this thread. But I'm "curious" about the extra RAM possibilities, no longer worried about writes to SSD from hibernation files when Win 10 creates a "Full" hiberfil.sys of only 40%, and no longer worried about writing pagefile when auto-management by Windows doesn't choose more than ~3 GB for pagefile size.