What does oc mean for memory?

[SHjiwani]

I was looking at a motherboard on pcpartpicker and it Saud that the only supported ram speed was 4800 mhz, but on their website it says that it supports things over 6000 mhz, but everything other than 4800 has "(OC)" after the speed and 4800 has "(JEDEC)." Can someone tell me what the difference is and weather or not u could use faster ram with the board?

[igormp]

4800 is the JEDEC standard, anything past it is considered OC and you need to enable XMP/EXPO to get it running, and it's not guaranteed that your system will work at higher speeds.

 

More often than not you can just turn on XMP and it'll work without problems tho.

[Needfuldoer]

JDEC is the base minimum speed the RAM will definitely run at.

 

OC is the overclocked speed the RAM should be able to run at.

[RONOTHAN##]

JEDEC is the speed that the CPU and motherboard are guaranteed to be capable of. OC is the speed that that they should in theory be capable of after XMP is enabled. 

 

In practice, the max OC speed should be treated as a guideline, not a rule. Motherboard manufacturers have the tendency to do all their testing for the OC supported frequency on a CPU with a golden memory controller (some manufacturers are worse than others, though they all do this to a degree), so while the board might say DDR5 8000 is supported, in practice with a middle of the road CPU you might only get say 7600 and with a terrible chip you might be limited to 6800 or lower. There's also differences in memory ICs and how hard they are to clock, so across the same board you might be able to get 6800 stable easily with one kit rated for 6800, but move onto a different 6800 rated kit and you might have issues (though admittedly this is a pretty rare scenario). Plus there can be new CPUs, BIOSes, and memory kits released that dramatically change the memory support, where it might only originally been rated for something like 6000 or 6400, but now with a new CPU and memory kit it can do 7200+ for instance. 

 

The middle of the road kits are usually pretty reliable to work though, so as long as you aren't shopping too close to the top of the motherboard's rated RAM speed you should be golden. 

[SHjiwani]

1 hour ago, RONOTHAN## said:

JEDEC is the speed that the CPU and motherboard are guaranteed to be capable of. OC is the speed that that they should in theory be capable of after XMP is enabled. 

 

In practice, the max OC speed should be treated as a guideline, not a rule. Motherboard manufacturers have the tendency to do all their testing for the OC supported frequency on a CPU with a golden memory controller (some manufacturers are worse than others, though they all do this to a degree), so while the board might say DDR5 8000 is supported, in practice with a middle of the road CPU you might only get say 7600 and with a terrible chip you might be limited to 6800 or lower. There's also differences in memory ICs and how hard they are to clock, so across the same board you might be able to get 6800 stable easily with one kit rated for 6800, but move onto a different 6800 rated kit and you might have issues (though admittedly this is a pretty rare scenario). Plus there can be new CPUs, BIOSes, and memory kits released that dramatically change the memory support, where it might only originally been rated for something like 6000 or 6400, but now with a new CPU and memory kit it can do 7200+ for instance. 

 

The middle of the road kits are usually pretty reliable to work though, so as long as you aren't shopping too close to the top of the motherboard's rated RAM speed you should be golden. 

So if the max oc speed is 6600 then something in the 5ks should be fine?

[RONOTHAN##]

43 minutes ago, SHjiwani said:

So if the max oc speed is 6600 then something in the 5ks should be fine?

Yeah. Even 6000 should be no problem on every DDR5 board and CPU I'm aware of, just going above that gets complicated real quickly