Hi lbar0518
Quote"/ "Can i OC my Ram to 3000 or 3200 using xmp and leave the CPU stock" End Quote/
XMP profiles are in accordance with JDEC standards and set at 2133-2400MHz. With OC RAM these profiles don't work and require manual tuning (in Bios) of Primary Timings and Voltage to obtain their rated SPD. I have found that slight CPU Overclock helps when overclocking RAM to obtain stability.
The i7-8700K has official support for 2666Mhz and they do scale well so although manual tuning is required, 3000-3200Mhz can usually be obtained.
Quote:/ "is there a negative effect in fps is i choose to OC only the ram?" End Quote:/
No negative effect just Overclocking RAM however this is unrealistic as CPU OC and RAM OC accompany each other for stability.
Quote:/ "if CPU OC is needed what is the safe multiplier should i input? End Quote:/
The safety you refer to is dependent on your cooling system and the CPU sample. Overclocking the CPU requires more CORE voltage. The higher you go the more heat generated which is exponential at each increase of the Multiplier.