5900X undervolting and TDC/EDC values

[highduke]

I settled at -28 all core atm and seems fine for a few days in various loads. What I did notice is it doesn't reach 140W power cap anymore. Stays at 130W max in full load. So that got me thinking, it must hit the current limits, which are TDC/EDC values.

When I activated PBO I set those to stock values, 90A/140A. I went back and increased them (proportionaly, 2:3 or something) until I hit power limit again, 140W. These extra 10W added some extra performance, and around -2 extra on all core (had to go at most -26 or crashed). I'm at 100A/155A atm.

Anyone tried this? Increased current limit and got a few extra all core points for undervolting, stable?

[PDifolco]

When I had a 5900x it was stable at -30 on slower cores, -20 on average ones and -15 on best ones

With that I could push it to 220W PPT, tho the last 30w didn't add much to performance, so I ran at 180W

Can't remember TDC/EDC values I used...

[highduke]

Is it worth trying to tweak this value per core?

Forgot to mention that I'm on Linux and a recent kernel changed something which made the system crash with similar UV offset as in Windows. Seem to be recommended to move 4 points higher in BIOS (all core in my case) to match Windows voltages. But increasing the current limits seems to solve this need. Been running for 24h with no crashes, did all kinds of testing.

[freeagent]

You are heavily gimping that CPU with such low power limits. They love extended limits. I ran my 5900X at 260/170/200 -25 AC, +200MHz. She rips. Does about 523GFlops in Linpack Xtreme, does the full 260w..

[highduke]

Wow, that's a lot. I do have a MSI B550-A Pro which seems to be in the A-tier list for VRMs (200A).

Is that 260W PPT, TDC of 170A and EDC of 200A?

Where would I add the extra 200MHz offset in BIOS? I like the low power states for general browsing/youtube use.

edit: I do have a Dark Rock Pro 3 on it, so should be able of max 250W.

[highduke]

I actually went the other way, 130W/90A/110A. In full load all are close to 100% and temps are pretty low, 67C. With -28 all core.

Cinebench score dropped like 5-6% vs 180W/140A/190A or something crazy like that. Temps were way higher, not worth it for me.

[freeagent]

I get about 23,650 with PBO in R23 on my 5900X, temps at about 75c.

[highduke]

I get around 20500 atm but don't go over 70C.

Tried a lot of testing but zero errors, OCCT and Prime95. Still OS randomly reboots at -30 and -29 all core. Dunno how to check which cores are failing. -28 seems fine atm.