Used 3000mHz ram

[samunars]

Hi everybody, I've found an interesting offer on 16 gb of 3000 Mhz RAM (like these). They're in good condition (claims the seller). The only thing that bugs me is why he's selling them: he says it is because they're not compatible with his mobo (a MSI X370 Gaming Plus) but work perfectly on a friends computer running an i7700k. My build would use a msi b350m gaming pro mobo and a ryzen 5 1600. Is there any risk for incompatibility here? 
PS He claims "not all 3000mhz ram are the same, so the fact that a mobo supports ram up to 3200Mhz [his does] doesn't mean that that ram will run at 3000Mhz, it depens on the compatibility between the two components". Is there any truths to this?

[Damascus]

It probably won't run at 3000mhz but if you manually OC it you may get close.

[domininiquew]

i have the same kit in 32GB, it does run ok at 2933Mhz but not at 3000Mhz (automatic overclocking), it is annoying if you do not know it, as the mobo will throw error or boot at 2133Mhz,  but stll it works fine with manual settings

[aezakmi]

3000+ mhz ram are incompatible with some ryzen models, check if your mobo and cpu are compatible before buying

[domininiquew]

Just updated to BIOS 3404 (ASUS performance fix), ans still had to manually set the RAM to 2933Mhz, together with all my overcloking settings, so automatic support for 3000Mhz memory stays whishfull thinking

[domininiquew]

BIOS 3803 is out

and it did work at 3000Mhz for some 2x8GB vengeance kit on the  motherboard Asus prime X370 pro (as seen on level1tech forum), though not for me at standard 1.35v with my 2x32GB kit, and caused me some other headache with FAN setup, so a not warmly advised possibility.