So I just rebuilt my rig in a new case to give me better clearance with my EATX mobo. I was in a corsair 5000d and went to a Lian Li o11 XL. During this process I decided to try the distro plate to make all my routes easier. Originally I had a corsair pump/res combo. The timing worked where I also upgraded to a 13900k from my 12900k and sold my 12900k to a friend. 
 
Anyway, I ran into issues initially where my loop wouldn't even fully fill up with the ddc pump that came with the distro plate. That one was powered off a fan header and after some research tons of people complained about it being DOA, barely working etc so I ordered a new upgraded DDC pump and a heatsink from EK installed that and the loop seemed to fill up fine and work. This pump was powered by a sata power cable I believe and was much higher powered so I assumed that was my only issue. Now that I have my rig built and OS installed I am starting to worry something else is wrong. 
 
here are my specs before I go any further: 
 
Intel 13900k (stock with small undervolt right now, -50mv, trying to get temps under control)
Kingpin KPX Thermal Paste
Thermal Grizzly Contact Frame
Corsair XC7 RGB Pro waterblock
EVGA Z690 Kingpin Mobo, BIOS 2.03
Corsair Dominator DDR5 6200 CL36 (running at 6800 with no issues, using Lummi daily 6800 CL32/1T setup in kingpin BIOS, just added this and passed memtest just fine)
EVGA 3090 Kingpin with EVGA waterblock (small OC for now while troubleshooting, +85 core, +750mem)
1TB and 2TB WD BLack SN850 nvme
O11D Distro Plate with Updated DDC 4.2 Pump
Corsair XT Hardline Tubing 14mm with Corsair Fittings
2x 360mm XR5 Radiators Corsair 
ThermalTake Pacific TF2 Temp/Flow Meter (off right now, not showing flow and is alarming so not sure if it's broke or not)
10x AL120 Lian Li Fans
Corsair Commader Pro
Lian Li Hub
Lian Li O11 XL Case
 
So running anything CPU intensive for instance R20/R23 my cpu instantly throttles going over 100c and then is really only running like 4.5ghz during the R23 run. I am thinking something is wrong. I know people have complained about the cpu running hot stock and having issues with AIO's, even 360 ones, but this seems extreme. I assumed my custom water cooling loop had enough with 2x 360 rads to deal with this, my last loop with 12900k and the same 3090 (different loop/case) had no issues with temp like this. I also added the contact frame this time around so I expected even better temps. 
 
As I mentioned above, my flow meter is unplugged but still in the system as it alarms constantly from a no flow condition which I don't buy as there has to be some flow as my gpu during benching has gone up to 500w and temps remain reasonable. I also read review saying they see the same thing and this flow meter is basically trash. I plan to get rid of this and either replace it with a better one or maybe a mechanical one or just do no flow meter.
 
My thoughts on leading possible causes:
1. Water block for CPU mount issue? I am not sure how but maybe I screwed this up, never seemed to have an issue before but maybe the contact frame doesn't like to work with this block?
2. This water block isn't enough to handle this maybe? Maybe upgrade to one of the newer EK ones. 
3. Blockage in system maybe? Maybe crappy flow meter? Maybe I am not getting actual good flow? With my last setup I could see water flowing but with the way the distro plate works I can't see crap. I find this hard to believe it's a flow issue as I would think my GPU would overhead instantly but I dunno. 
4. Many parts sat for a while (months) while waiting for this upgrade to get finish so maybe some corrosion is hindering something. I tried to drain/dry everything and put caps on everything so I doubt it's this but I dunno. 
 
I was considering just buying a newer EK block and when I swap that I will get a new mount, be able to change flow meter out so maybe taking care of 2 or 3 most likely issues. 
 
Is there anything I am missing? Any advice?
 
Here is a pic:

do you know what your delta T ambient:coolant is?

Were you careful in ensuring the inlet and outlet of the block were connected properly? Temps can certainly be affected if water is flowing in the reverse direction intended for the block.  Since you mentioned your 3090 temps are fine, it feels like its something with the cpu block itself in either the direction of flow or possibly mounting. Did you happen to test the pump outside the case before you installed it? I have a habit of plugging it in and running water through a bucket before I install a pump to give me a piece of mind that it actually pumps. But I can't imagine the pump having enough flow to cool the GPU but not enough flow to not cool the CPU, though.

How come you didn't plug the pump into the pump header on your mobo?  This header should run the pump at full speed constantly which is what you want.  The fans on your rad can be controlled by the CPU PWM fan header and these will cycle depending on cpu temp. 
 
It makes sense that you are experiencing crazy throttling if you have the pump on a fan header..  You are likely seeing crazy spikes in temps as your mobo cycles your pump through low and high speeds, but it is incredibly inefficient to how a loop should work.  You want water/coolant constantly flowing over your waterblock coldplate, dissipating heat.  Again the rads will cycle, but you shouldn't see as severe heat spikes in your loop.

 


Sharp looking RIG