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Z390-I VCCIO and System Agent...What do you guys set your voltages at?

tml4191
Level 7
Hardware:
- Z390-I motherboard
- (16gb x 2) 32gb Corsair Vengeance RGB 3000Mhz C15 (CMR32GX4M2C3000C15)
- 9900K CPU

I put VCCIO and System Agent voltages to Auto, which set VCCIO to 1.328 V and System Agent to 1.232 V.

I asked around on YouTube and Reddit, and nearly everyone said I could lower it.

So I lowered the VCCIO to 1.232 V in bios, which was the same as the System Agent voltage, and it jumped to 1.264 V, according to HWiNFO64 and HWMonitor.

Corsair also mentioned to leave it on auto for stability reasons, but I have yet to run into any problems at 1.264 V, even after succesfully passing OCCT medium packet, AIDA64 and MEMTest64.

How far should I lower the VCCIO and System Agent before calling it a day? I just don't want to have to CMOS reset. Some people even said go as low as 1.1xx.

What do you guys run your VCCIO and System Agent voltages at?
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mdzcpa
Level 12
tml4191 wrote:
Hardware:
- Z390-I motherboard
- (16gb x 2) 32gb Corsair Vengeance RGB 3000Mhz C15 (CMR32GX4M2C3000C15)
- 9900K CPU

I put VCCIO and System Agent voltages to Auto, which set VCCIO to 1.328 V and System Agent to 1.232 V.

I asked around on YouTube and Reddit, and nearly everyone said I could lower it.

So I lowered the VCCIO to 1.232 V in bios, which was the same as the System Agent voltage, and it jumped to 1.264 V, according to HWiNFO64 and HWMonitor.

Corsair also mentioned to leave it on auto for stability reasons, but I have yet to run into any problems at 1.264 V, even after succesfully passing OCCT medium packet, AIDA64 and MEMTest64.

How far should I lower the VCCIO and System Agent before calling it a day? I just don't want to have to CMOS reset. Some people even said go as low as 1.1xx.

What do you guys run your VCCIO and System Agent voltages at?




Rule of thumb: Run it as low as you can with stability. Lower is better. Less heat. Less breakdown of the CPU. Auto defaults pretty high to accommodate higher speeds ram, densities, IMC variability and cpu overclocks. That said, no need to push it too low and run into random instability. Run it only low enough to produce a consistently stable operation.

I run mine at VCCIO 1.264 (as measured) and SA 1.248. That's a chunk under Auto settings (which defaults at an eye watering 1.32v) so I'm happy right where I'm at and I'm not going to bother pushing down further for the time being. I may tinker again when I have time and see if I can drop it a bit more later. But I'm not feeling pressed to do it.

Feel free to step it down another notch or 2 if you want to experiment. Eventually it will crash which isn't a big deal. But you won't want to be on the hairy edge of stability.

Thanks for the tip!

Agreed, mine defaulted crazy high. I lowered down to 1.28/1.20 I think but I believe vccio can go much lower. I ended up getting my normal oc first and chasing that one last.

Silent_Scone
Super Moderator
Auto rules are designed to cover worst case silicon scenarios to ensure that users who aren't looking to tune manually don't have to. The amount of voltage needed on both rails is CPU dependant.

My 9900K is comfortable at around 1.1v on IO and 1.15v on SA at 4GHz.
13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

Silent Scone@ASUS wrote:
Auto rules are designed to cover worst case silicon scenarios to ensure that users who aren't looking to tune manually don't have to. The amount of voltage needed on both rails is CPU dependant.

My 9900K is comfortable at around 1.1v on IO and 1.15v on SA at 4GHz.




Those voltages seem right for the CPU at 4Ghz. What RAM speed are you running? Pushing higher speeds (3800+) and up usually requires these voltages to be pushed up as well. I'm curious to see how low other users with a 5Ghz OC on the CPU and RAM speeds over 3600mhz are running.

For giggles (and because its the weekend and I have time) I dropped IO and SA down to 1.225v each just to see. Maybe I will work on these today. The thread has inspired me 🙂 This is the last piece of my OC puzzle that I needed to manually work on. It's nice to have finally scored a CPU that clocks so well (5.1Ghz at 1.3v that supports ram at 4000mhz)

mdzcpa wrote:
Those voltages seem right for the CPU at 4Ghz. What RAM speed are you running? Pushing higher speeds (3800+) and up usually requires these voltages to be pushed up as well. I'm curious to see how low other users with a 5Ghz OC on the CPU and RAM speeds over 3600mhz are running.

For giggles (and because its the weekend and I have time) I dropped IO and SA down to 1.225v each just to see. Maybe I will work on these today. The thread has inspired me 🙂 This is the last piece of my OC puzzle that I needed to manually work on. It's nice to have finally scored a CPU that clocks so well (5.1Ghz at 1.3v that supports ram at 4000mhz)


Running my 9900k at 5.1Ghz on all 8 cores, and I'm running (reported by BIOS and HWiNFO) VCCIO at 1.248v (have ran at 1.23v) and VCCSA at 1.28v with 4266 Mhz ram running at 3900 Mhz. Sadly I can only run stable with the 0602 bios, the other newer ones for my Z390-E seem to cause serious memory instability, and the 0805 BIOS CPU instability as well. I wish I knew what was changed so I can dial it in better vs Auto settings for some (manual RAM timings don't seem to work, but Auto reads the exact same thing).

mdzcpa wrote:
I'm curious to see how low other users with a 5Ghz OC on the CPU and RAM speeds over 3600mhz are running.

1,3V @ IO & SA in bios
4x 8 GB, 4,3 GHz

Well, here is where I have settled.

IO @ 1.2v
SA @ 1.225v

RAM running at 4000mhz @ 1.35v 17-17-17-37
CPU runs at 5.1ghz all cores, AVX -2, 1.3v
Cache running @ 4800mhz


Feeling happy :cool:

mdzcpa wrote:
Those voltages seem right for the CPU at 4Ghz. What RAM speed are you running? Pushing higher speeds (3800+) and up usually requires these voltages to be pushed up as well. I'm curious to see how low other users with a 5Ghz OC on the CPU and RAM speeds over 3600mhz are running.

For giggles (and because its the weekend and I have time) I dropped IO and SA down to 1.225v each just to see. Maybe I will work on these today. The thread has inspired me 🙂 This is the last piece of my OC puzzle that I needed to manually work on. It's nice to have finally scored a CPU that clocks so well (5.1Ghz at 1.3v that supports ram at 4000mhz)


I was talking about memory speed, as we were speaking about VCCSA and VCCIO. The CPU is at 5GHz with no AVX offset @ 1.34v. Memory is 4GHz CAS 16-17-17 1T. As I stated above, these rails are CPU specific.
13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090