x370 and 3800x problems with ram 4xDIMM

[Maquak]

Hi 

 I have upgraded CPU in my system form 1700x with 4xDIMM to 3800x and write speed went down almost in half and my question is this effect for x370 having problems with my new CPU ? I can see lag in my system now in Chrome .. i am planning to upgrade my motherboard ( Asus TUF Gaming X570-PLUS WI-FI i can get it with warranty for half price so ..  ). Maybe removing 2 DIMS will fix it ? 

[ramava]

it *looks* like you've got XMP running and it's actually running at 3200, which was my first thought. For the sake of argument, I'd try it with 2 sticks, just make sure their in the right slots for 2 sticks.

 

Were you only running 2 sticks on the X370 board?

 

I did run the test on my 5600x on an X570 board with 4x8 GB DDR4-3200 CL16 to see and got very similar numbers to your 3800x. The slower write may be from using 4 sticks instead of 2.

[steve2563]

Ryzen 3800x is a single-CCD CPU. That's why you see the write bandwidth halved. 

[ramava]

11 minutes ago, steve2563 said:

Ryzen 3800x is a single-CCD CPU. That's why you see the write bandwidth halved. 

The 1700x was also single CCD though.

[steve2563]

Zen 2 is a totally different design.

 

As of wikipedia:

 

Zen:

The memory, PCIe, SATA, and USB controllers are incorporated into the same chip(s) as the processor cores. This has advantages in bandwidth and power, at the expense of chip complexity and die area.

 

Zen 2:

Zen 2 moves to a multi-chip module design where the I/O components of the CPU are laid out on its own, separate die, which is also called a chiplet in this context.

 

 

https://community.amd.com/t5/processors/low-memory-write-speed-zen2-3700x/td-p/51401

 

This is pretty much an expected result. The link between the Core die and IO die only writes at 16B/cycle, so you will see half the bandwidth that the 2000/1000 series hand.  Also, because the IO and core dies are now separate, there is added latency when communicating with RAM, as the signal now has to pass from the core die to the IO die, and then to memory.

All the single chiplet Ryzen 3000 series chips have this lower write speed.  The double chiplet versions (3900X and 3950X) are not affected, as they have two chiplets which can pass data to the IO die simultaneously. 

In reality, this won't really affect performance much, as the 3000 series double the available L3 cache to compensate for the higher memory latency.  The system will read/write from RAM far less often, so you have a net performance gain.

 

Edit:

@Maquak, make sure that you have the latest chipset drivers installed.

[Maquak]

16 hours ago, ramava said:

it *looks* like you've got XMP running and it's actually running at 3200, which was my first thought. For the sake of argument, I'd try it with 2 sticks, just make sure their in the right slots for 2 sticks.

 

Were you only running 2 sticks on the X370 board?

 

I did run the test on my 5600x on an X570 board with 4x8 GB DDR4-3200 CL16 to see and got very similar numbers to your 3800x. The slower write may be from using 4 sticks instead of 2.

THX i forgot about this .. after some work everything is flying even CTR 2.1 works on my old x370 now i know my 3800x is a Golden Sample