How does memory support in terms of cpu and chipset work? Specifically for Ryzen

TechGod · March 4, 2017

Is the support for it on the CPU itself or chipset? With the release of Zen+ could they add quad channel support to AM4 without a new mobo or new socket? I.e Is the memory related stuff all on the CPU?

If quad channel is reliant on a new mobo would the socket remain the same?

Sorry for the possibly confusing phrasing of the questions.

Electronics Wizardy · March 4, 2017

am4 will be dual channel only. Due to how its connected, you can't add more channels without more pins.

mariushm · March 4, 2017

No, the AM4 socket only has the pins for dual channel DDR4

You'd need a new socket to support quad channel. Each channel probably needs around 140-160 traces going to the CPU (pins on the socket) so you can imagine on socket AM4 (1331 pins) already maybe about 300 of those are just for memory.

On AM4 , the processor has a built in light "chipset", which offers a a few sata ports and a few usb ports and for more stuff, the processor offers a pci-e 3.0 x4 link (4 GB/s in both directions) to which you can connect a chipset, which is basically like a network switch to which are connected a usb controller , a sata controller, and a pci-e controller which creates a few pci-e 2.0 links to connect stuff like onboard sound card, onboard network cards etc etc

So technically with AM4, you can create motherboards that have no chipset and everything will work.

The server processors based on Ryzen will have support for more than dual channel. Basically, they plan to take up to four of these 8 core / 16 thread chips and connect them together to make a processor with 32 cores / 64 threads and of course, since each processor will have 2 ddr 4 channels, the server processor will have 2 x 4 = 8 DDR4 channels, each with 2 slots .. so 16 sticks of DDR4 memory.