[SOLVED] Ryzen CPU with RAM

[XRT910]

I was looking at the Ryzen 5900X and the memory specifications stated that it supports up to 3200 MHz, but they recommend the 5000 series to be paired with 4000 MHz for optimal performance. Why?

Would it be better to get 3200 MHz ram with low CAS Latency over a 4000 MHz ram?

I plan on mainly gaming, but this recommended 4000 MHz has been troubling me when the specification says up to 3200 MHz.

I'm looking at the G.Skill RAM. I currently have the Trident Z RGB, but the Neo version is "Optimized for Ryzen" what does being optimized for Ryzen mean?

 

[siaan312]

The difference won't be huge either way.
A couple of precent at best.
4000mhz ram is so much more expensive, especially with low latnecys that it makes any sense to buy.

You can get for like, 2/3rds the price of 4000mhz cl18, 3600cl16 or cl17, which perform almost the same.

As long as you go above 3000mhz, don't worry about it too much.

 

[DMAN999]

What motherboard are you going to use with the 5900x.
The motherboard and CPU will determine the maximum speed of RAM you can use/achieve.

My 3700x states it's maximum RAM speed is 3200 BUT I run my RAM at 3733 on an Asus ROG Strix X470-F without any issues.

 

[XRT910]

The Asus Rog Crosshair VIII Hero, an X570 board.

 

[XRT910]

Using some G.Skill RAM at the moment, which one would be better? They plan to make new RAM for 5000 series though. It is stated on https://www.tomshardware.com/news/gskill-trident-z-neo-ram-amd-ryzen-5000-cpus and I'll probably get one of those instead.

3800 MHz, CAS Latency 14-16-16-36
or
3200 MHz, CAS Latency 14-14-14-34

They are roughly the same price with the 3800 MHz being a little cheaper, but these were for the 3000 series.

 

[DMAN999]

3rd Gen AMD Ryzen™ Processors
4 x DIMM, Max. 128GB, DDR4 4800(O.C.)/4600(O.C)/4400(O.C)/4266(O.C.)/4133(O.C.)/4000(O.C.)/3866(O.C.)/3733(O.C.)/3600(O.C.)/3466(O.C.)/3400(O.C.)/3200/3000/2933/2800/2666/2400/2133 MHz Un-buffered Memory

ROG Crosshair VIII Hero | ROG Crosshair | Gaming Motherboards｜ROG - Republic of Gamers｜ROG USA

AMD Ryzen 3000 series ATX motherboard with Aura Sync, SupremeFX, ROG Audio, Dual M.2, Realtek LAN, Dual Lan , M.2 heatsink and USB 3.2 Gen 2

rog.asus.com

They don't list RAM speeds for the 5000 series CPUs But they are most likely the same or even faster than the 3000 series CPUs limits.

Using some G.Skill RAM at the moment, which one would be better? They plan to make new RAM for 5000 series though. It is stated on https://www.tomshardware.com/news/gskill-trident-z-neo-ram-amd-ryzen-5000-cpus and I'll probably get one of those.

3800 MHz, CAS Latency 14-16-16-36
or
3200 MHz, CAS Latency 14-14-14-34

They are roughly the same price with the 3800 MHz being a little cheaper.

Between those 2, I personally would get the 3800 C14 kit.

PS
What is the exact model of your current RAM kit ?

 

[XRT910]

F4-3200C14D-32GTZR
That is my current one. I am currently using intel.

I still have no clue what the benefit of faster RAM does since the Ryzen 5900x can only run up to 3200 MHz right?

 

[DMAN999]

The 5900x can run up to 4800 RAM kits on that Asus Crosshair VIII Hero MB.
Look here:
https://dlcdnets.asus.com/pub/ASUS/...Crosshair_VIII_Series_Memory_QVL_20200211.pdf

But you can certainly use that kit you have and it will most likely work fine.
I would definitely try it before buying a new kit.

 

[XRT910]

Would the 5900x limit the ram speed to 3200 MHz? I don't really know how ram actually works and what exactly is affected by it.

 

[DMAN999]

Would the 5900x limit the ram speed to 3200 MHz? I don't really know how ram actually works and what exactly is affected by it.

No, with a 5900x on that Asus Crisshair VIII, you can run RAM up to 4800.

Read this for info about RAM speed on Ryzen systems:
https://www.eurogamer.net/articles/...-amd-ryzen-memory-frequency-vs-timings?page=4

 

[XRT910]

That helped a bit. I've been googling quite a bit and I guess it's (MHz/CAS)? The higher the number the better at above 3200 MHz?

Going back to the cpu specs, how come intel for example (mine is i7-8700k) specifies "up to" 2666 MHz ram just like Ryzn 5900X with the "up to" 3200 MHz ram? What does that "up to" even mean if ram can be run higher? Is the "up to" base clock and higher than that is overclocking?

After googling some more, I always thought ram usage was exclusive to the cpu. This isn't the case right? Main reason why I'm confused on different ram speeds.

 

[DMAN999]

Technically any RAM speed over your RAM kits base speed (usually 2133 to 2400) is overclocking.
The "Up to" speed is just the speed that the CPU manufacturer (Intel and AMD) guarantee to work with the CPU's Memory controller.

 

[XRT910]

I guess I always thought having higher RAM than the "up to" would have been useless, but it really isn't. Thanks for helping me figure it out!