RAMbleed - which DDR4 has TRR enabled?

[gzorn]

With the new RAMbleed attack making some news, I'd like to understand my vulnerability level.
The news reports say that we should use DDR4 with TRR enabled, but I'm unable to find a way to check if my server RAM (Samsung M391A2K43BB1-CPB) has it. No info available in dmidecode and the specs from Samsung don't mention it.
I've seen indications that Micron DDR4 has it. Any info from other vendors? It's sad that the messaging is 'upgrade your RAM', but we have no idea which RAM is good.

Yeah, I know that the attack requires local access (and thus is lower severity).

 

[gzorn]

Ok, so it appears that Samsung claims to use TRR in all their DDR4, according to Once thought safe, DDR4 memory shown to be vulnerable to “Rowhammer” . However, that's not a primary reference.

I've not yet found rowhammer-vulnerable RAM based on testing by memtest86 (laptop, desktop, or server).
The docs PassMark MemTest86 - Memory Diagnostic Tool - Troublingshooting Memory Errors suggest that memtest86's rowhammer test may not be thorough enough to catch the 'worst case scenario' for rowhammer. Is there anything better out there?