Z790 PG Lightning + I9-13900K running into limits
Printed From: ASRock.com
Category: Technical Support
Forum Name: Intel Motherboards
Forum Description: Question about ASRock Intel Motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=25231
Printed Date: 19 Jul 2025 at 10:51am
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com
Topic: Z790 PG Lightning + I9-13900K running into limits
Posted By: Lidove
Subject: Z790 PG Lightning + I9-13900K running into limits
Date Posted: 24 Dec 2022 at 2:23am
I am using a Z790 PG Lightning BIOS 3.04 beta with an I9-13900K, 1200W PSU, Win 10. All on stock settings.
360 mm AIO CPU cooler, all temperatures are low (CPU 28°C idle)
Even when no other application is running, HWiNFO64 immediately shows performance limit due to
- IA: Max Turbo Limit
- RING: Max VR voltage, ICCmax, PL4
These kick in immediately after I reset the HWiNFO-values.
Furthermore it does not take long until "IA: Electrical Design Point/Other (ICCmax, PL4, SVID, DDR RAPL" limit turns on.
Is this normal on stock settings? What do I need to change so these limits do not kick in all the time?
-------------
Z790 PG Lightning
I9-13900K
DDR5-6400
RTX 4090
|
Replies:
Posted By: Gatt59
Date Posted: 27 Dec 2022 at 4:27pm
Hello,
are you sure that the PG Lightning with her 14 50A Power Phase is enough to manage a 13900K + RTX 4090?
|
Posted By: Lidove
Date Posted: 27 Dec 2022 at 5:42pm
Why not? The 13900K is listed in the CPU compatibility list and the 4090 gets its power directly from the PSU.
-------------
Z790 PG Lightning
I9-13900K
DDR5-6400
RTX 4090
|
Posted By: Gorn42
Date Posted: 29 Dec 2022 at 9:43am
|
How does the power calculation work? As I understand, the Mobo's CPU power is taken from the 12V rail, so is that nominally 12V * 50A = 600W, or do we have to somehow use the number of phases in the calculation? That 600W figure is more than twice the official power limit of 253w for the 13900K, or am I mistaken?
|
Posted By: Lidove
Date Posted: 29 Dec 2022 at 7:44pm
I can't even tell you whether the 50A refers to input or output side or per phase or whatnot. My understanding is that the maximum load of the VRM design of this mainboard is more than 13900K maximum requirement, but the answer is not as simple as this.
It is not only about the number or power phases and their maximum load, but also about their quality, which also affects module heat generation and voltage drops especially during load transients, both of which may lead to instability even if the maximum power specs seem to be sufficient. This is where it gets complicated because there seems to be no clear specification that allows you to directly compare VRM systems.
Common wisdom has it that "more power phases are better", but since this eventually translates into 200 euro mainboard vs 1200 euro mainboard, this suggestion is not particularly helpful.
-------------
Z790 PG Lightning
I9-13900K
DDR5-6400
RTX 4090
|
Posted By: Gatt59
Date Posted: 30 Dec 2022 at 2:29pm
Well, my last experience with instability was with an ASRock Z590 PG4. It could theoretically manage the 11th Gen Intel processor but it was extremely unstable with the 11900K, not only while stressing it with benchmark but even while gaming.
I upgraded to the Z590 Taichi and never had a problem.
I understand the price issue but if you are running the top CPU and GPU, choosing one of the cheapest ASRock MB is not a good choice, IMHO. And btw, a Z790 Taichi is about 600 Euro. Even a Z790 Steel Legend at half that price would be a wiser choice, IMHO.
|
Posted By: Lidove
Date Posted: 30 Dec 2022 at 7:14pm
Thanks for the info. It is really a shame that there is no way to directly compare the VRM capabilities of various boards. I don't find it satisfying to spend a couple hundred euros more for a mainboard with additional features I don't need, only because that mainboard hopefully has better VRM. I hope that there will be clear(er) VRM specifications in the future.
-------------
Z790 PG Lightning
I9-13900K
DDR5-6400
RTX 4090
|
Posted By: Gorn42
Date Posted: 31 Dec 2022 at 6:53am
When I deciding what z790 board to choose, I noticed that all the high-end boards had WiFi, which I consider a security risk. Taking the Taichi, as an example, can the WiFi module be physically disabled, either by pulling out a card or setting a jumper? I don't trust just disabling it in the BIOS flash settings.
Due to this concern, I ended up choosing a lesser board, the PRO RS. It has the 14+1+1 phases @ 50A, which I believe is similar to the OP's specs.
With the 13900K, it is possible that these boards are overvolting the CPU by default ("AUTO" settings)? If so, that would explain hitting the power ceiling so quickly. I have a dedicated thread posted on that. I have not yet attempted to run Prime95, but I will, and that should reveal whether I'm in a similar boat.
|
Posted By: Gatt59
Date Posted: 31 Dec 2022 at 7:32am
Overvolting I don't know, however I know for sure that the deafult BIOS setting is "no limits" for the CPU power. This means that the MB allows the CPU to run without power limits. If I want to apply the Intel recommended settings (125W-253W for the i7-13700K) I have to do it in the BIOS.
Every time I upgrade the BIOS it comes back to "no limits" and I have to do it again.
-------------
ASRock Z690 Taichi
Intel i9-13900F
Noctua NH-U12A Chromax Black
PNY RTX 4080
|
|