Question Is 6400mhz CAS 32 worse than 6000mhz CAS 30 when paired with Ryzen 7 9800X3D?

[MitchellReece]

Hello,

I want to upgrade my CPU to the 9800X3D which is on a newer socket so I will need a new motherboard and RAM to pair with it.

After a bit of research it seems like the ideal speed and CAS latency to pair with the 9800X3D are 6000mhz/s and CAS 30.

I currently have G.Skill Trident Z RAM and I want to stay with this brand, but have since taken a liking to the G.Skill Royal RAM design.

I was able to find G.Skill Trident Z with the right specs, 6000mhz/s and CAS 30... but with G.Skill Royal RAM I can only find speeds from 6400mhz/s up to 8400mhz/s and varying CAS latency from 32-40.

Although there is a link on G.Skill's product page to the Royal sticks with the right specs, it seems at any retailer they begin at 6400mhz/s at the lowest and with a CAS latency of 32.

It makes sense that instead of 6000mhzs & CAS 30 you get 6400mhz/s & CAS 32, but I just want to confirm whether it's still an ideal speed/latency to pair with a Ryzen 7 9800X3D?

Or, do you think it would be more preferable for me to stay with Trident Z sticks since the ideal specs are available?

Here are the two options for RAM I am considering buying; one & two.

Appreciate any advice you can give to steer me in the right direction and make the right purchases! 😀

 

[faalin]

For gaming the lower CL # will be better, if you're doing anything long calculations like production work then the faster speed will be better.

 

[Lutfij]

After a bit of research it seems like the ideal speed and CAS latency to pair with the 9800X3D are 6000mhz/s and CAS 30.
True!

I've helped a friend build a system with Corsair Dominator Platinum's rated to run at DDR5-6600MHz CL32 on an MSI B650i Edge WiFi + 7800X3D, hasn't complained since it was built.

You can go with anything higher than DR5-6000MHz but how much more are you spending is the question. My friend didn't have any issues with spending since it was a PC he'll be building in nearly 30 or so years.

FYI, those ram kits you're looking at are meant for Intel's platform, I wouldn't invest in them unless it's expressly mentioned they have AMD's E.X.P.O baked into the kit/advertised on them.

What motherboard are you looking at?

Moved thread from Components section to Memory section.

 

[Aeacus]

It makes sense that instead of 6000mhzs & CAS 30 you get 6400mhz/s & CAS 32

Well, calculate the RAM latency.
Formula: (cas latency/ram transfer speed) x 2000 = latency in nanoseconds

Whereby;
(30/6000) x 2000 = 10 nanoseconds
(32/6400) x 2000 = 10 nanoseconds

Both are equal in terms of performance.

I just want to confirm whether it's still an ideal speed/latency to pair with a Ryzen 7 9800X3D?

6000 MT/s, or at most 6400 MT/s, while paired as low CAS Latency as possible.

View: https://www.youtube.com/watch?v=b-WFetQjifc

 

[MitchellReece]

After a bit of research it seems like the ideal speed and CAS latency to pair with the 9800X3D are 6000mhz/s and CAS 30.
True!

I've helped a friend build a system with Corsair Dominator Platinum's rated to run at DDR5-6600MHz CL32 on an MSI B650i Edge WiFi + 7800X3D, hasn't complained since it was built.

You can go with anything higher than DR5-6000MHz but how much more are you spending is the question. My friend didn't have any issues with spending since it was a PC he'll be building in nearly 30 or so years.

FYI, those ram kits you're looking at are meant for Intel's platform, I wouldn't invest in them unless it's expressly mentioned they have AMD's E.X.P.O baked into the kit/advertised on them.

What motherboard are you looking at?

Moved thread from Components section to Memory section.

Thanks! I realized that the Royal Neo designs are made for AMD EXPO so will make sure I'm getting Neo.

I'm considering a motherboard out of these two options; one & two.

It seems like the Royal Neo designs don't go up to 64gb which eliminates that option for me, and I am left with 6000MT/s at CAS 28 or 6400MT/s at CAS 30.

I think I was willing to sacrifice 2-4 CAS latency so that I could get a 64GB kit, but they don't seem available so it's a toss up and I think I'll end up going with the lower CAS latency, which would also be in-line with what users Faalin & Aeacus have advised.

Do you think that the cheaper motherboard of my two options will limit my build whatsoever in comparison to the more expensive mobo?

 

[Aeacus]

Do you think that the cheaper motherboard of my two options will limit my build whatsoever in comparison to the more expensive mobo?

Here's AMD AM5 chipset differences:

Specifications​

	Direct Processor PCIe® Lanes	Direct Processor PCIe® Lanes	Chipset-Provided USB and SATA	Chipset-Provided USB and SATA	Chipset-Provided USB and SATA	Chipset-Provided USB and SATA	Chipset-Provided USB and SATA	Chipset-Provided USB and SATA	Chipset-Provided USB and SATA
	GRAPHICS	NVMe (PLUS PCIe™ GPP, UP TO)	USABLE PCIe® LANES TOTAL/PCIe® 5.0(UP TO)	RYZEN PROCESSOR OVERCLOCKING ENABLED	DDR5 MEMORY OVERCLOCKING ENABLED (Supports AMD EXPO™)	SUPERSPEED USB 5Gbps (UP TO)	SUPERSPEED USB 10Gbps (UP TO)	SUPERSPEED USB 20Gbps (UP TO)	MAXIMUM SATA PORTS (OR PCIe® 3.0, UP TO)	USB 4.0
X870E	1x16 or 2x8 PCIe® 5.0	1x4 PCIe® 5.0 plus 4x PCIe® GPP	44/24	Yes	Yes	2	12	2	8	STANDARD
X870	1x16 or 2x8 PCIe® 5.0	1x4 PCIe® 5.0plus 4x PCIe® GPP	36/24	Yes	Yes	1	6	1	4	STANDARD
B850	1x16 or 2x8 PCIe® 4.0	1x4 PCIe® 5.0	36/4	Yes	Yes	1	6	1	4	Optional
B840	1x16 PCIe® 4.0	1x4 PCIe® 4.0	34/0	No	Yes	2	2	-	4	Optional
X670E	1x16 or 2x8 PCIe® 5.0	1x4 PCIe® 5.0 plus 4x PCIe® GPP	44/24	Yes	Yes	2	12	2	8	Optional
X670	1x16 or 2x8 PCIe® 4.0	1x4 PCIe® 5.0 plus 4x PCIe® GPP	44/8	Yes	Yes	2	12	2	8	Optional
B650E	1x16 or 2x8 PCIe® 5.0	1x4 PCIe® 5.0 plus 4x PCIe® GPP	36/24	Yes	Yes	1	6	1	4	Optional
B650	1x16 or 2x8 PCIe® 4.0	1x4 PCIe® 4.0 (PCIe® 5.0 Optional)	36/0	Yes	Yes	1	6	1	4	Optional
A620 / A620A	1x16 PCIe® 4.0	1x4 PCIe® 4.0	32/0	No	Yes	2	2	-	4	Optional
PRO 665*	1x16 or 2x8	1x4 PCIe® 4.0 (PCIe® 5.0 Optional)	36/0	No	No	1	6	1	4	Optional
PCIe® 4.0
PRO 600*	1x16 or 2x8	1x4 PCIe® 4.0 plus 4x PCIe® GPP	28/0	No	No	0	0	0	0	Optional
PCIe® 4.0

*Only available through system suppliers. Check with your manufacturer for details.
Source: https://www.amd.com/en/products/processors/chipsets/am5.html#specs

As seen, with X870E, you'll get more usable PCI-E lanes, more USB and SATA ports and USB4 is given. PCI-E revision for GPU x16 slot is also newer/faster.

 

[Kona45primo]

You'll want to buy 2 32gb sticks for 64mb.

4 sticks of 16 will not run above 5200 or 5600mhz. It is out of the question.

6400mhz seams to be the upper limit of frequency for now, less reliable at those speeds, and possibly unattainable. Minimal gains over the more reliable 6000mhz.

For a solid more reliable solution I would stick with 2 32gb sticks @ 6000mhz as that appears to be the go to almost guaranteed to work without errors choice.

Anything beyond that may be more trouble than it's worth.