Ryzen memory performance and Infinity Fabric tuning options
Ryzen memory performance and Infinity Fabric tuning options
Hello everyone, a friend of mine just finished assembling his first desktop (https://pcpartpicker.com/user/Alec19/saved/yVFjHx) and asked about RAM speeds. He’s using a 5600G and relying on integrated graphics for light gaming. I understand that faster RAM helps with Ryzen, especially when paired with an APU. I know you need to enable DOCP to reach around 3600 MHz, but I was curious about the infinity fabric setting. First, is it okay to leave the FCLK frequency in auto mode? I’ve heard some advice suggesting the infinity fabric should run at about half the RAM speed for a 3600 MHz RAM, but the auto setting lists it at 1200 MHz. Is there any advantage to increasing it? Also, regarding the RAM-FCLK clock ratio, I’ve seen people recommending a 1:1 ratio with lower dimmed speeds (like 3900x) for 3600 MHz RAM. Am I misunderstanding? As for whether pushing FCLK higher is beneficial, I’m wondering if it’s better to stick with the stable setting below 1800 MHz, depending on how the 5600G handles clocks near that frequency. If you have any doubts about my answers, just let me know. I don’t typically work with Ryzen, as its performance isn’t ideal for my tasks. Thanks, Alec
Achieving optimal results requires matching the clock frequency to 1:1 with the memory clock (half of the RAM's MHz). Non-Apu chips usually handle higher frequencies than Apu ones, often surpassing 2000 MHz. Increasing the clock speed to twice the frequency can add latency, but this might be compensated if the memory operates quickly enough. Setting auto to 1200 MHz when RAM is at 3600 MHz could help; manually adjusting to 1800 MHz may boost performance. The supply voltage should stay below 1.2V. There could be scaling variations between 1.15V and 1.2V depending on the chip design.
Aim for at least 4000-4200 to beat the latency penalty versus 3600 1:1. Try setting fclk to its maximum, then memory, and match them to the highest 1:1 ratio before fine-tuning the timing. For my CPU, the IMC won’t exceed 4200mhz and actually runs better at 3733mhz with fclk at 1866 (my CPU’s cap). If your fclk stays low but your IMC and memory handle higher speeds, consider the approach from Alec19. Don’t forget to check the DDR4 OC guide I linked for you: https://github.com/integralfx/MemTestHel...guide/DDR4 OC Guide.md
I'll need to try a few approaches to fix this. Appreciate the guidance. It's really useful.