On my 3rd reseat of the water block, card was originally a hybrid card. That confusing gpu bracket has been flipped a couple times with no difference. Thermal paste is Thermal Grizzy Hydronaut. Block shows a perfect imprint of the GPU die in the paste. Also made sure the LED connector wasn't being pinched under the waterblock as I read a few instances of that happening. All screws are hand tight to the point of potentially stripping out with the first four screws installed being those that would provide the mounting pressure of the block to the die and then moving outwards with a final random check of all screws.

I don't seem to be getting the temps I, and even others, expect.

Loop setup is GPU only right now with a D5 pump running ~3000rpm, a PrimoChill EximoSX 240x40 rad with 2x Noctua NF-12 Chromax running ~1250rpm. This rad is in-taking fresh air.
Water temp is around 38-40C using the external temperature of the tubing. (Proper water temp sensor is on order)

Quick Heaven run at stock clocks yielded the following at 76F (24.4C) ambient temperature.
GPU1: 64C
GPU2: 55C
MEM1: 44C
MEM2: 55C
MEM3: 57C
PWR1: 45C
PWR2: 46C
PWR3: 50C
PWR4: 49C
PWR5: 44C

Playing some Far Cry New Dawn for about 45 minutes with memory +1300 (8300mhz reported in X1), core +140 (2055mhz reported in X1 once heat loaded), and voltage and power targets cranked up would see brief peaks at 70C and settling around the 65C range.

Thanks for the reply, bcavnaugh.
I'll definitely try replacing the hydronaut. I do actually have some kryonaut I have on hand to try with over the weekend while I get either the MX-4 or TT TF8 on order. That'll be reseat #4 and potentially #5.

I am wondering if having the GPU mounted vertically may be causing an issue with the waterblock now as well. I'd be pretty well stumped at that point if I'm still getting bad temps -- I imagine the rarity of getting a bad waterblock is really slim?

Great to hear the chance of a faulty block is low! I was dreading having to rma the block and switch back to the horridly loud hybrid setup my card originally had.

Definitely installed the card's block as flat as I could as I had to hand it partly over my desk due to the one tall video output.

I went ahead and switch to a standard horizontal position and observed a few air bubbles escape the block; but temperatures remain within 1C of my original figures.

Looks like I'm draining my loop again, cleaning the card up, and re-pasting with Kryonaut until I receive the MX-4. (Local MicroCenter doesn't have any in stock)

Thank you again, bcavnaugh.

1. Kryonaut is so much better than MX-4 that you should just keep the kryonaut once you put it in.
 
2. The GPU temperatures are about what I would expect from that water temperature and a properly installed and working block.  EK put out a blog recently about flow direction in GPU blocks.  There is a small preference that's worth 2-4 degrees C lower temperature rise.  Check to be sure that water flow is in the preferred direction in that block.
 
3. Suggestions to increase radiator area and/or air flow have merit since water temperature is the limiting factor here.

jab383
1. Kryonaut is so much better than MX-4 that you should just keep the kryonaut once you put it in.
 
2. The GPU temperatures are about what I would expect from that water temperature and a properly installed and working block.  EK put out a blog recently about flow direction in GPU blocks.  There is a small preference that's worth 2-4 degrees C lower temperature rise.  Check to be sure that water flow is in the preferred direction in that block.
 
3. Suggestions to increase radiator area and/or air flow have merit since water temperature is the limiting factor here.

I see no reference to any EK Parts in this Thread but you are correct about the New EK CPU Water Blocks.
 
The Hydro Copper Water Block has No Flow Direction Requirements and can be setup many ways.
From https://www.evga.com/support/manuals/files/400-HC-1289-B1.pdf

 

I would also look into your flow rates of your pump.  Crank it to 11 and see if that helps.
 
I have found that with my D5 running at 40% (so I can't hear it) there isn't enough surface turbulence to keep the heat transfer optimal.  I have my pump speed based on CPU temps currently, and I find occasionally that a heavy GPU load with little/no CPU load doesn't get the pump to spin up enough.  And I have a 420 and a 360 trying to keep it cool.

Baratak

bcavnaugh
One of my Cards Folding, Coolant Temperature is 29°C Room Temperature 68°F or 20°C

So jealous, my house isn't that cool in the middle of winter  :)

This last Winter I have see as low as 46°F or 7.77°C inside and at that point is when I turn off my Window Fans

It does seem a bit warm for a custom cooling setup, even with those cool ambient temps but I would test the GPU at stock settings first, see what you get and compare that to your OC'd temps.

Have you also tried maxing out the rad fans to see a difference?
 
Is there a flow meter to the loop?  Sometimes showing 3000 RPM for the pump, doesn't equate to a efficient 1-1.5 GPM flowing loop, even 0.8 is fine as well but your loop doesn't look too complex to be an issue unless of course there's some blockage of some type. 

Did you clean the gear before assembly?

Is the rad positioned higher than the loop?

A few shots of your PC setup to show what it all looks like could help.  Use imgur to host your picks here via 'insert image'.