No XMP lowest CAS Latency?

[ScaryFatKidGT]

So ram speeds with DDR5 are so fast now on a 13900k, if you don’t want to enable XMP for stability and are running 5600MHz native is it then beneficial to find the lowest CAS sticks of 5600MHz or is there a limit there as well?

[filpo]

6 minutes ago, ScaryFatKidGT said:

So ram speeds with DDR5 are so fast now on a 13900k, if you don’t want to enable XMP for stability and are running 5600MHz native is it then beneficial to find the lowest CAS sticks of 5600MHz or is there a limit there as well?

well no better latency is always better. But pay attention to subtimings. If you have a kit of CL30* ram with subtimings going up to 96 then it won't be as good as you think. corsair's vengeance ddr5 seems to be more consistent with their ram timings (if not the best)

 

Also if XMP is so common that many ram manufacturers have come to support it. I would assume they've made it more stable 

[ScaryFatKidGT]

17 minutes ago, filpo said:

well no better latency is always better. But pay attention to subtimings. If you have a kit of CL30* ram with subtimings going up to 96 then it won't be as good as you think. corsair's vengeance ddr5 seems to be more consistent with their ram timings (if not the best)

 

Also if XMP is so common that many ram manufacturers have come to support it. I would assume they've made it more stable 

I have had issues in the past with XMP over clocking and with the base speed being 5600, XMP one goes to what? 6800 or I think I’ve seen 7200.

 

Maybe I’ll just ask, whats the moneys no object best 2x32gb sticks of 5600MHz RGB DDR5? Preferably white or at least with a white RGB defuser on the top?

 

I could live with 2x16GB sticks if there is something significantly faster but I only want to run 2 sticks for stability and OCing as well so 64GB would be preferred. 

[filpo]

Just now, ScaryFatKidGT said:

have had issues in the past with XMP over clocking and with the base speed being 5600, XMP one goes to what? 6800 or I think I’ve seen 7200.

 

should be the highest speed your ram supports

 

1 minute ago, ScaryFatKidGT said:

Maybe I’ll just ask, whats the moneys no object best 2x32gb sticks of 5600MHz RGB DDR5? Preferably white or at least with a white RGB defuser on the top?

 

I could live with 2x16GB sticks if there is something significantly faster but I only want to run 2 sticks for stability and OCing as well so 64GB would be preferred. 

if 64 gigs is preferred then I would actually go with 6000mhz ram since its widely supported, even by amd

(btw switch your country to wherever you are when you click on the link)

This G Skill kit has decent sub timings and is 64 gigs G.Skill Trident Z5 RGB 64 GB (2 x 32 GB) DDR5-5600 CL28 Memory (F5-5600J2834F32GX2-TZ5RS) - PCPartPicker

[Somerandomtechyboi]

5600c30, 6000c32, or (intel) 6400c32 is enough, going faster than that you tune for max freq that your cpu/mobo can hit then tune the subtimings yourself (trfc, trc, trrd-l/s, twr, tfaw = 1, all the same rank diff rank diff dimm tertiaries, trefi = 66666, 111111, etc.)

 

These are all hynix a dies all capable of 8000+ just limited by cpu and mobo choice, and no you are not getting faster rams without manual tuning, doesnt matter how high of a bin (which xmps usually dont work anyways) its a hard wall

[porina]

50 minutes ago, ScaryFatKidGT said:

So ram speeds with DDR5 are so fast now on a 13900k, if you don’t want to enable XMP for stability and are running 5600MHz native is it then beneficial to find the lowest CAS sticks of 5600MHz or is there a limit there as well?

https://www.anandtech.com/show/16143/insights-into-ddr5-subtimings-and-latencies

Table here of the JEDEC defined standard timings. If it isn't one of those timings, it is not standard even if it is at a standard speed.

 

42 minutes ago, filpo said:

Also if XMP is so common that many ram manufacturers have come to support it. I would assume they've made it more stable 

As an overclocked specification, there is never 100% guarantee XMP or EXPO will work. There are endless posts here about people having problems once they enable it.

 

Moderate speeds are generally fine.  The more extreme you go, the more chance of a problem there may be. I have no doubt that individually, the CPU, mobo and ram might support beyond JEDEC speeds and timings, but put them together and it is hit and miss what will actually work stably.