Problem - Activating SVM leads to significant BCLK variations
Problem - Activating SVM leads to significant BCLK variations
When I turned on SVM Mode for virtualization, my BCLK began to vary between 97.8x and 98.9x, leading to a significant downclocking of the clock speeds on FCLK, DRAM, and CPU. I’m unsure why this happens or whether it should be reported to ASUS. With SVM disabled, the BCLK stays around 99.8x–100x, and the CPU can reach its rated 4550MHz instead of capping at 4450MHz. I’ve turned off both SB Spread Spectrum and VRM Spread Spectrum, disabled C-states, and adjusted power limits, but nothing other than disabling virtualization resolves the issue. Fortunately, I don’t use it heavily—just occasionally for Windows Sandbox—but I’d prefer keeping it enabled for convenience. My motherboard is X570 Crosshair VIII Hero Wi-Fi, running BIOS version 4304 (enhanced with Curve Optimizer for 5800X3D), and I’m using an R7 5800X3D with 4x16GB DRAM.
We're initially concerned about thermal management. Are you running a forced overclock or is this your standard base configuration?
It's not about heat, the CPU stays cool thanks to a 360mm AIO and hits 80°C during Linpack Extreme—the toughest test I can give it. Under normal conditions it stays around 60°C. This isn't connected to temperature changes; it also occurs when idle and the CPU drops to 28°C.
Without any temperature problems, I think there might be a built-in buffer involved or the SVM isn’t getting accurate system information. I’d reach out to ASUS and ask their engineering team about this. It could stem from poor coding on the backend, or it might actually provide a more genuine hardware reading instead of the vague specs they usually list.
I've recorded these details right after posting. I suspect this might be a problem, especially since my 3900X runs on an older BIOS version, but I won't investigate further as it would require changing the CPU and re-flashing the BIOS. I'm just curious if anyone has more information at this point. When I used a 4770k, I faced a similar BCLK issue linked to Windows, which resolved after a clean install, though it wasn't related to virtualization.
I resolved the issue by turning off Memory Integrity in Core Isolation settings on Windows, as well as disabling Hypervisor, Sandbox, and restarting the PC. Once SVM was enabled, the BCLK performance remained stable at 99.98x to 100x. However, virtualization functionality still didn’t work unless I adjusted the Hypervisor and Sandbox settings back. It seems I’ll have to manage this temporarily while looking for a better solution.
I wonder if I should have asked this earlier too—what exactly are you aiming for? Lol. Without a clear goal, troubleshooting tends to wander off track. I thought you were focused on setting up a VM or VM Server. But when you mentioned that solution, it seems like I misunderstood your main objective. Those tricky Windows settings often interfere with basic tasks. I was really working hard to install .NET 3.5 on an NI PXI chassis and even disabled most group policy features that might have blocked updates from the internet. I changed registries, tweaked policies, and dug deep into log updates to find where things went wrong. Eventually, I discovered a bad or corrupt sector in the spinning platter was causing the update failure. After a month of effort with several teams trying different fixes, it turned out to be a failing hard drive that wasn’t showing up in tests. It’s really a waste of time.
I'm just using Windows Sandbox to open non-trusted links and some programs since it's simple and doesn't require setting up a new VM. However, for virtualization I need to adjust BIOS settings, which involves enabling SVM Mode. Once that's done, my BCLK starts behaving erratically. I suspect the issue is linked to enabling/disabling single options in BIOS. Since I already have Windows Sandbox installed, it affects BCLK when SVM is toggled. Enabling it again causes problems. I haven't tried VMware yet to check if it causes the same problem. These kinds of issues are really frustrating—they make you want to be very stubborn about fixing them. I've had similar experiences, like when my parents bought a Sony TV and it couldn't connect to Wi-Fi despite trying all sorts of solutions. The fix was turning off the automatic clock in the date and time settings. That makes sense now.
Are you considering Hyper-V or using the box itself as a VM? I’m trying to make sure I understand correctly. I usually run VMs with dedicated cores and memory for performance, but this is the first time I’m running a full VM without that setup. Also, I’m not sure how the time sync feature on the TV would work—especially since it could disrupt WiFi connections if timing is off. I remember in my military days we needed precise synchronization within seconds to keep systems in sync. That makes me think this might be a tricky issue. I also noticed a previous ticket about Wi-Fi connectivity problems linked to time sync errors.