Current I have an Adata XPG Gammix d30 3000 Mhz 8gb Cl 16, it's hard to find the same, so shall I go for a G.Skill Ripjaws V 3600 Cl 18 or G.Skill Ripjaws V 3200 Cl 16.(The 3600 mhz version is really cheap).
Z370 with i5 8600KSimple answer, don't.
Long answer, you're better off getting the same kit of ram as you're working with now if you want to up the capacity or work with only DDR4-3200MHz or DDR4-3600MHz only. Mixing and matching rams will only lead to stability. If the current ram kit is hard to find, sell them off and pick out the latter kits(3200MHz or 3600MHz) of ram.
What is the make and model of your motherboard and processor?
Well good, stability is what we wantMixing and matching rams will only lead to stability.
The 3600 is really cheap because its cl18 which means its slower than your 3000 ram.Current I have an Adata XPG Gammix d30 3000 Mhz 8gb Cl 16, it's hard to find the same, so shall I go for a G.Skill Ripjaws V 3600 Cl 18 or G.Skill Ripjaws V 3200 Cl 16.(The 3600 mhz version is really cheap).