Intel vs RAM speeds

Tristerin · October 17, 2018

When I built my Ryzen 7 1700 RAM prices were ridiculous. I elected to go with the cheapest I could get just to get it posting (wifes PC fried, Im very budget oriented, and best option to get her back gaming and within budget) which is 2133 MHZ.

I haven't done any research on WHY the RAM speed really helps the Ryzen line, but its the overall chorus I am hearing so clearly that is the case. I plan on upgrading soon to the fastest RAM her mobo will utilize (not sure yet she has the ASUS B350 Prime) once I do some research and then taking the 2133 MHZ ram and MAYBE actually build myself an Intel based system.

The only reason I am thinking this is because I already have the ram, and from what I am reading Intel processors are not as reliant on it, as is evident with Zen architecture.

Can someone give me a cliff notes reason of why I should or shouldn't use this ram with an intel based system? Will it create bottlenecks to the point I should just sell it and get better ram all around - should I overclock if I go intel on this slow RAM? Should I just OC it with the B350 board?

TL;DR

I am a newb with RAM and Ryzen, don't know crap about timings and their importances all around, and would like to be educated (and should I even use the 2133 MHz on an intel build or just get better RAM all around - its Patriot Viper 2x8gb DDR4 2133MHZ)

Thanks!

ARikozuM · October 17, 2018

If you already have it, keep it. Faster RAM usually helps at the minimum framerates and synthetic benchmarks. It rarely helps unless you're pushing your CPU to the limit of its I/O.

If you need to buy a new kit for reassurance, go with a good 3000MHz 2x8GB kit. Lower timings means less wasted time (nanoseconds) on waiting for a call to proceed. Don't get too extravagant. If you're paying an extra $5 or $10 for an upgrade in speed and latency is okay, but any more than that is a no-go for returns. I would start looking at the 2666 and only go up to 3000MHz.

Mira Yurizaki · October 17, 2018

The primary reason why Ryzen works better with faster memory is that each core in the Zen architecture is designed to make use of a interconnect bus called Infinity Fabric. This connects all of the cores together and to other parts of the processor. In the case of Threadripper and EPYC, Infinity Fabric connects processor dies to each other.

The problem is that Infinity Fabric's speed is tied to the memory controller's speed. Here's a block diagram of a processor die:

Notice how everything between cores, I/O controller, and memory controller is 32 bytes per cycle. So the faster you can push the memory controller, the more bandwidth you can shove down Infinity Fabric.

The reason Intel doesn't have this problem is that they use a different interconnect:

The cores talk to each other and the System Agent via the ring bus (or a mesh interface for larger core count processors). The System Agent is capable of "translating" the faster speed of the ring bus to slower speeds of the other interfaces and vice versa.

Tristerin · October 17, 2018

8 minutes ago, ARikozuM said:

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6 minutes ago, M.Yurizaki said:

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Thank you guys so much!

So technically if I am looking to REALLY push the Ryzen 7 (gaming PC only) I should upgrade the RAM but in reality its a difference (for gaming) of a few FPS while gaming? If so then I am really not interested in building an Intel just cause lol - Im Team Red.