What is this new ram stick from what brand?
There shouldn't be any compatibility issues, but both sticks will run at the lowest of the two ram speeds, which will be 2600 mhz.
Recommended to use 2 of the same speed, though you can use them both, you'll just have to drop the clock speed of the faster RAM to the slower RAM or else you could run into crashes and BSODs.
Also I presume their CL timings aren't the same either, so that would be another issue.
Conclusion: You can mix them but you'll have to lower performance of the new kit. However, mixing RAM is generally not recommended.
Is a crucial ballistix too.
I see, I would get the ram with the same clock speed then...
Thanks for the help!
Yep, pretty much. Greg, a youtuber, did a nice video about this.
View: https://youtu.be/uaR6Ea8Hl0w
Perhaps if you plan on upgrading later on you should get the faster RAM now and decommission the old one, or sell it. And when you have the money just get the same speed RAM for that new one.