XMP functionality isn't working for Patriot Viper B.
XMP functionality isn't working for Patriot Viper B.
I've used two 16GB Patriot Viper Steel cards for a year each and haven't managed to get them to run XMP. They're labeled at 4133MHz with XMP support, but I'm only reaching around 3600MHz with solid timing (14-14-14-14-34) and a clock frequency of 1800MHz at 1.42V. Any settings above 3600MHz won't work, even with more relaxed timing at 1.45V. I initially thought my older 5600X wasn't capable, but I've since switched to a 5800X3D and still haven't succeeded. Any suggestions?
Raise the SOC voltage to 1.15V. This should be ideal for most CPUs and will enable higher memory speeds. However, since you're using the 5800X3D, its large L3 Cache doesn't prioritize memory performance, so switching from 3600CL14 to 3800CL14 won't significantly boost performance.
Additionally, according to what I know, reaching 3800MHz causes the Infinity fabric to slow down and may hurt performance. Running at 3600MHz is the suggested setting for Ryzen processors for good reasons. This seems like standard advice among those familiar with Ryzen CPUs.
Ryzen Infinity fabric speed is linked to RAM speed, starting at a 1:1 ratio up to around 3700 MHz. Beyond that point, the fabric operates at a 1:2 ratio, effectively cutting your Infinity fabric speed in half if your RAM reaches 3800 MHz.
Most Ryzen 5000 series processors can achieve 1900MHz FCLK without significant performance drops or WHEA warnings. Some models even support 2000MHz FCLK before issues arise, though these are uncommon. If you expect a slower speed, it will automatically lower, but adjusting memory frequency can help maintain stability. AMD tends to be cautious with recommendations. For Ryzen 7000 series, many run at 6200MT/s in single mode, yet they suggest 6000MHz as a safer choice for reliability and the minority of CPUs that fall short. For Ryzen 5000, the recommended speed has been raised to 3733MT/s, but finding compatible kits is rare, so it rarely influences decisions. By default, FCLK stays at 1800MHz, with no upper or lower limits.
Running at half speed even at 1800 mhz indicates increased latency. Unclear why someone would try to improve performance when higher clock speeds are achievable, especially since better Infinity fabric clocks often need a solid motherboard and good BIOS. Overall, I wouldn't suggest it.
The most affordable boards can achieve very high FCLK clocks, the key factors being the AGESA version and the CPU, not the motherboard. You don’t have to settle for 1800MHz—this is the default setting you can adjust even on budget A320 boards. Pursuing speeds above 3600 CL14 isn't necessary here; it's mainly about cost, not performance gains unless you specifically aim for XMP compliance. The 5800X3D doesn’t prioritize memory speed, so pushing beyond 3600 CL14 won’t improve results.
I've been operating at those speeds and regained my memory in 2021 without any XMP issues. Lowering the voltage causes occasional crashes, but I'm still stable. If improvements aren't visible, I'll revert the voltage to default and maintain the 3600MHz frequency. Thanks for all the feedback!
XMP won't function in that configuration. You might achieve a 1:1:1 ratio, but it's not worthwhile. Unless you can handle around 2100FCLK with MEMS at about 4600C16.