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RYZEN DDR4 MEMORY, WHAT YOU NEED TO KNOW!

nlel1975 said:
I think Ryzen CPU are more optimised to work with faster RAM, so access times with fast RAM are better with Ryzen then they used to be with other CPU but the fact is pure CPU performance still isn't affected by RAM speed.
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I'm not making this up. The infinity fabric within the ryzen Cpu has a working speed that is directly related to the ram speed you use.

If you have faster clocked ram then the speed of the infinity fabric within the cpu will increase to match the speed of the ram.

This is a fact. It has been confirmed by nvidia. It has been tested by others.

I've added two links.



https://www.techpowerup.com/231585/amd-ryzen-infinity-fabric-ticks-at-memory-speed


https://www.tomshardware.com/reviews/amd-ryzen-5-1600x-cpu-review,5014-2.html
 
Fair enough, I'm not going to argue with you, it just goes against everything I understood about computers. I'd like to see a CPU based benchmark with fast RAM compared to one with slower RAM to see the differences in pure CPU processing power because of the faster RAM.
 
nlel1975 said:
Fair enough, I'm not going to argue with you, it just goes against everything I understood about computers. I'd like to see a CPU based benchmark with fast RAM compared to one with slower RAM to see the differences in pure CPU processing power because of the faster RAM.
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Games are dependent on latency and faster RAM means the IF runs at a higher speed meaning quicker communication across CCX units.

However,some games love more RAM speed on AMD or Intel - one game being Fallout 4:

https://static.techspot.com/articles-info/1171/bench/Fallout.png
https://static.techspot.com/articles-info/1089/bench/RAM.png
 
nlel1975 said:
My point exactly it's to do with faster access times (communication) not CPU processing power. The RAM doesn't do any processing that's down to the CPU.
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But a ryzen cpu is made with 2 ccx units which are joined by the infinity fabric. Any communication between those ccx units goes over the IF, so does communication with other aspects of the CPU die.

Because of the way the infinity fabric works on ryzen cpus it is tied to the speed of the memory being used. So the faster your memory the faster that connection between ccx's on the cpu and the other components on the cpu.

With other cpus this isnt the case. Its just a quirk of the zen architecture. So faster ram isn't just faster ram in a ryzen system. It is also a faster interconnect within the cpu itself.
 
nlel1975 said:
That's as maybe but fast RAM won't make a CPU perform its calculations any faster it's purely a communication thing between the memory and CPU.
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No it isnt.

The infinity fabric is a connection within the cpu. By having faster ram on ryzen you increase the speed of the connections within the cpu. Not just between the cpu and ram.

The cpu has many parts and they are joined by the infinity fabric. This is all on the die. So by increasing the speed of the infinity fabric you increase the speed at which these parts communicate. This is an increase in speed or a decrease in latency on the ryzen cpu.

This approach is specific to the zen architecture.

The intel equivalent is the ring bus or mesh. However there is no similar association with the speed of the ringbus and memory speed for intel cpus.
 
I'm old school the CPU is the central processing unit and the RAM is the random access memory. Now you're telling me the RAM does some of the processing. I could understand that the communication between the CPU and RAM is faster but not that the RAM actually does some processing. So maybe the RAM should now be called RAMPU. Random access memory processing unit.
 
No the ram does no processing.

You are absolutely right about what the cpu and ram do and dont do. That hasnt changed.

However, on zen architectures only, the speed of the ram directly influences the speed of the internal interconnect within the cpu which is called the infinity fabric.

Its like, you turn up the speed of the ram and the cpu is aware of this, so it automatically turns up the speed of its internal communication channels to match it. The two arent linked, but the speed of the ram informs the speed of the infinity fabric within the cpu.

So faster ram = faster infinity fabric.

The ram doesnt take on any processing.

This extra speed within the cpu in response to the increase in ram speed results in lower latency within the cpu.

The article i linked to earlier explains it better than i can. Sorry if i've not explained it well. I'm on mobile and trying to do dinner and be with the family at the same time. :(
 
Distracted is right, the RAM speed corresponds to the "infinity fabric " connections within the CPU Arch, there are many articles about it, the performance increase is real but in real terms not really noticeable day to day but as these are used for rendering etc where every second counts there is a benefit to having the fastest ram and tight timings running on Zen.

edit put it better than i did :)
 
Faster memory has always been better what's changed? I still doubt I'd see increases in pure CPU calculation benchmarks which is why my 3D Mark CPU score is as good as anybodies but maybe some benchmarks more targeted at the improvements you talk of would show this up more.
 
nlel1975 said:
Faster memory has always been better what's changed? I still doubt I'd see increases in pure CPU calculation benchmarks which is why my 3D Mark CPU score is as good as anybodies but maybe some benchmarks more targeted at the improvements you talk of would show this up more.
Click to expand...

My terminology here isnt accurate.

But think of it like this.

Faster ram in a ryzen system automatically applies an overclock to the frontside bus.

The benefits of faster ram arent just that the faster ram speed helps speed up the system.

The faster internal bus speed caused by the overclock allows the cpu to complete its tasks and communicate with memory and pcie quicker.



In this scenario the frontsidebus is infinity fabric.


This is a very basic way of looking at it but hopefully it helps illustrate what is happening.
 
Well I am still happy with my recent upgrade, I had an i5-2500k with 16GB DDR3 1333 and a Radeon 7950 3GB. Now have Ryzen 5 2600 with 32GB DDR4 2133 and a Radeon RX 580...

5objwp.png
 
I'm guessing the upshot is it would have been even better if you had faster ram. Done some more reading and your ram speed is a 1:1 ratio to the internal connection speedbetween the CCX units inside the cpu. The faster they talk to each other, the faster they get the information they need to do their work.
 
SB118 said:
I'm guessing the upshot is it would have been even better if you had faster ram. Done some more reading and your ram speed is a 1:1 ratio to the internal connection speedbetween the CCX units inside the cpu. The faster they talk to each other, the faster they get the information they need to do their work.
Click to expand...

Even with my old DDR3 RAM running at 1333 I never felt RAM speed was an issue.
 
nlel1975 said:
Even with my old DDR3 RAM running at 1333 I never felt RAM speed was an issue.
Click to expand...

Yes, because you weren't running a chip where ram speed is directly related to the internal speed of the cpu when you were using ddr3.

Done some more reading, you remember how we would have our ram at some odd ratio, 1333:1000, 800:1333, 566:800, all sorts of odd stuff so that the cpu and ram would sync? Now it's 1:1, your ram speed is directly related the internal CPU speed.

And it's just occurred to be we've been feeding an epic troll for the last day, well played.
 
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