[SOLVED] Corsair Vengeance LPX C15 kit pairing with C16 kit (3000mhz 16gb)

[Chainedsoma]

So I had 16gb C16 ram, butI've finally managed to find a kit for cheap (25 bucks!), the only problem being the timing difference. My kit is c15 3000 and the new one is c16 3000. CPU R5 3600 MOBO MSI b450m pro-vdh max

On the first attempt (C15 plugged in 2+4, C16 plugged in 1+3) the PC did not boot up and just ran on a black screen, no video output.
After playing around with it for a bit, reset the cmos, testing each module and figuring out if maybe the slots were damaged (all OK) I decided to plug them in the other way around (so, C15 at 1+3) and now for some reason it boots just fine.

Problem is they run at 2133 instead of the 3000 they should. I turned on XMP but the frequency just sits at 2133 for all, no change. Tried manually setting to 3000, but I guess it also didn't like that since I got a black screen again after it and it didn't fix itself.
After that I reset the CMOS again to revert all changes but I still want it to run at the good speed so I need tips. I'm thinking the problem might be with the C15 running at C16.

Is this ram actually useless to me? How can I set it to that speed? Will my c15 ram even run at C16 3000 anyways?
Thanks for the help.

 

[logainofhades]

You do not want to ever mix ram. Whether it works, or not, is always a gamble.

 

[Chainedsoma]

You do not want to ever mix ram. Whether it works, or not, is always a gamble.

I understand, but I still want to figure out if I could manually set it up that way. If not I might get lucky this weekend and trade the c16s for some c15s, which i suppose should work fine.
Also performance loss going from c15 to c16 is not really a concern, should be negligible.

 

[geofelt]

Ram is sold in kits for a reason.
A motherboard must manage all the ram using the same specs of voltage, cas and speed.
The internal workings are designed for the capacity of the kit.
Ram from the same vendor and part number can be made up of differing manufacturing components over time.
Some motherboards, can be very sensitive to this.
Ryzen, in particular is very sensitive to ram specs.
This is more difficult when more sticks are involved.
Ram must be matched for proper operation.

You can try to get things to run by specifying speed and cas specs explicitly in the bios and increasing the ram voltage in the bios past the normal xmp spec.

 

[Zerk2012]

I understand, but I still want to figure out if I could manually set it up that way. If not I might get lucky this weekend and trade the c16s for some c15s, which i suppose should work fine.
Also performance loss going from c15 to c16 is not really a concern, should be negligible.

Manually set the speed and timings to the 16C set and up the voltage to 1.37

 

[Roland Of Gilead]

Hey there,

You could also try Gear down mode. IIRC it allows CL15 to run better.

 

[Chainedsoma]

Manually set the speed and timings to the 16C set and up the voltage to 1.37

Turns out MSI mobos have this "try it" functionality that allows you to choose a timing and speed without having to reset cmos every time it fails. I just slapped on C16 3200mhz which should be equivalent to c15 3000mhz and it boots into windows just fine. Thanks for an actual reply Zerk2012, I'll mark your post as the correct answer

 

[Chainedsoma]

Hey there,

You could also try Gear down mode. IIRC it allows CL15 to run better.

I will also give this a try right now and see how that works now that I'm at it. Thank you as well for the answer