DDR5 RAM Speed for new Mobo

[Boro123]

OK guys i'm just interested, which CPU supports 7600 MHZ DDR5 from AMD, cause i'm planning to get the fastest RAM for my mobo which supports up to 7600MHZ and not planning to upgrade it in the future, and tell me if its really worth going up to 7600 or should settle down on 6000?

[GuiltySpark_]

You're in for a rude awakening, unfortunately. Your board can say whatever it wants regarding support, and its true, but current CPU's simply are not going to work with kits that fast out of the box (unless you really, really know what you're doing and make some compromises for benchmark bragging rights). 

 

All you need for Zen4 right now is a since, simple kit of DDR5-6000 CL30-32 and call it a day. There really isn't anything a normal user is going to benefit from by buying faster, not really. 

[RONOTHAN##]

21 minutes ago, Boro123 said:

should settle down on 6000?

Yes. 

 

For reference, AMD CPUs have two memory controller modes: 1:1 mode where they have better latency but a lower maximum speed, and 2:1 mode where they clock memory significantly better but has a very high latency penalty. 1:1 mode by default tops out at 6000MT/s, and with some tuning you can usually get it to somewhere between 6200 and 6600MT/s depending on how good your CPU's memory controller is. For speeds above 6000MT/s where 2:1 mode will be default, there will be a massive latency penalty and you don't start to overcome that until you get to speeds of over 7600MT/s and doesn't fully become better until 8000MT/s, and by the time you get to those incredibly high speeds you can run into weird memory instability (I.E. memory errors once every few hours) and general variance of CPU to CPU for little to no benefit in memory performance. 

 

Plus memory overclocking is a thing, and with how consistent DDR5 is, getting a lot of 6000 CL30 rated kits to 8000+ is relatively trivial assuming the CPU and motherboard are capable of it (I.E. the XMP of an 8000 rated kit actually works in the first place). This is an area that can be a bit complicated as you will have to figure out what memory IC is on the kit you just bought, where it's only the Hynix 16Gb A die and Hynix 24Gb M die kits that do that, and most people aren't willing to learn (understandably so) the more complicated aspects of memory overclocking, but it's just to illustrate that getting a lower rated kit now doesn't mean that you'll actually be limited to that lower speed in the future. 

[Boro123]

26 minutes ago, RONOTHAN## said:

Yes. 

 

For reference, AMD CPUs have two memory controller modes: 1:1 mode where they have better latency but a lower maximum speed, and 2:1 mode where they clock memory significantly better but has a very high latency penalty. 1:1 mode by default tops out at 6000MT/s, and with some tuning you can usually get it to somewhere between 6200 and 6600MT/s depending on how good your CPU's memory controller is. For speeds above 6000MT/s where 2:1 mode will be default, there will be a massive latency penalty and you don't start to overcome that until you get to speeds of over 7600MT/s and doesn't fully become better until 8000MT/s, and by the time you get to those incredibly high speeds you can run into weird memory instability (I.E. memory errors once every few hours) and general variance of CPU to CPU for little to no benefit in memory performance. 

 

Plus memory overclocking is a thing, and with how consistent DDR5 is, getting a lot of 6000 CL30 rated kits to 8000+ is relatively trivial assuming the CPU and motherboard are capable of it (I.E. the XMP of an 8000 rated kit actually works in the first place). This is an area that can be a bit complicated as you will have to figure out what memory IC is on the kit you just bought, where it's only the Hynix 16Gb A die and Hynix 24Gb M die kits that do that, and most people aren't willing to learn (understandably so) the more complicated aspects of memory overclocking, but it's just to illustrate that getting a lower rated kit now doesn't mean that you'll actually be limited to that lower speed in the future. 

Thank you for your time and knowledge.