Watercooling a Vega 64. What Rad Setup for best Airflow / Cooling?

[Stuttgart]

I know i know - the rule of thumb is: 1x120rad for each component + 120 for headroom. But i dont feel quite well with this rule regarding the temperatures of the vega, especially under load.
Currently im running a 360mm (30mm thickness) rad in front + 280mm (60mm thickness) rad at the top. 
i did some testing and these are the temperatues im getting:

Following Temperatures are Coolant temperatue readouts. 

 

Ambient Temps at all tests 23-24°C
Pump always at 100%

 

1st Test:
360mm front as intake, 280mm top as exhaust, phobya dc12-220, Fractal GP fans:
idle - climbing up to 32°C, once reached, temps stay at 32°C. 

Gaming load (The Division 2) for 30min - water climbing up to almost 50°C, GPU at 52°C.
at that point i was concerned about my tubing and i cancelled the test.

 

2nd Test:
360mm front as intake, 280mm top as exhaust, phobya dc12-400, Arctic SP fans:
idle - about 29°C (+-1°)

Gaming load (The Division 2) for  1h  - water at 40°C, gpu at 45°C.

 

3rd Test:
360mm front as exhaust, 280mm top as exhaust, phobya dc12-400, Arctic SP fans @62% speed constant:
idle - 26°C (+-1°)

Gaming load (The Division 2) for 1h - water at ~38°C, GPU ~43°C

A little side note regarding the 3rd test:
I am fully aware of the fact that i have a huge amount of negative pressure inside the case, but ironically this setup cools my components the best.
One explanation im giving myself is that the front radiator which acts as an intake, heats up the whole system, including the top radiator. 

Im thinking about buying a 140mm rad for the exhaust slot at the back of the case and switching the 360mm to the top, removing the 280mm completely.
This would be the only configuration i would have some kind of airflow, with 3 140mm fans in front blowing into the case and the 140mm+360mm rads exhausting the fresh air. 
If im using the 280 + 360 i will always have one of the following:
a) negative pressure 

or
b) warm air pumped into the case

But at this point i am not sure if the ~500mm rad surface will be enough for cooling my 350w tdp vega64 compared with an i7 4770k at 130w tdp. 
Please advise. Im desperate.

Edit:
I dont have any chance to use external radiators like a MoRa or similiar. My Fractal R6 has no connectors for external rads.


 

 

[Daniel Z.]

A 360mm and 280mm are more than enough.

[ChrisZH]

33 minutes ago, Stuttgart said:

I know i know - the rule of thumb is: 1x120rad for each component + 120 for headroom. But i dont feel quite well with this rule regarding the temperatures of the vega, especially under load.
Currently im running a 360mm (30mm thickness) rad in front + 280mm (60mm thickness) rad at the top. 
i did some testing and these are the temperatues im getting:

Following Temperatures are Coolant temperatue readouts. 

 

Ambient Temps at all tests 23-24°C
Pump always at 100%

 

1st Test:
360mm front as intake, 280mm top as exhaust, phobya dc12-220, Fractal GP fans:
idle - climbing up to 32°C, once reached, temps stay at 32°C. 

Gaming load (The Division 2) for 30min - water climbing up to almost 50°C, GPU at 52°C.
at that point i was concerned about my tubing and i cancelled the test.

 

2nd Test:
360mm front as intake, 280mm top as exhaust, phobya dc12-400, Arctic SP fans:
idle - about 29°C (+-1°)

Gaming load (The Division 2) for  1h  - water at 40°C, gpu at 45°C.

 

3rd Test:
360mm front as exhaust, 280mm top as exhaust, phobya dc12-400, Arctic SP fans @62% speed constant:
idle - 26°C (+-1°)

Gaming load (The Division 2) for 1h - water at ~38°C, GPU ~43°C

A little side note regarding the 3rd test:
I am fully aware of the fact that i have a huge amount of negative pressure inside the case, but ironically this setup cools my components the best.
One explanation im giving myself is that the front radiator which acts as an intake, heats up the whole system, including the top radiator. 

Im thinking about buying a 140mm rad for the exhaust slot at the back of the case and switching the 360mm to the top, removing the 280mm completely.
This would be the only configuration i would have some kind of airflow, with 3 140mm fans in front blowing into the case and the 140mm+360mm rads exhausting the fresh air. 
If im using the 280 + 360 i will always have one of the following:
a) negative pressure 

or
b) warm air pumped into the case

But at this point i am not sure if the ~500mm rad surface will be enough for cooling my 350w tdp vega64 compared with an i7 4770k at 130w tdp. 
Please advise. Im desperate.

Edit:
I dont have any chance to use external radiators like a MoRa or similiar. My Fractal R6 has no connectors for external rads.


 

 

Im running a radeon VII and i have a 360 45mm rad up top and a 240 30mm in front. My temps for that are really good, overclocked pretty heavily. Although im using a cougar conquer case, so that could be why.

[Skiiwee29]

I have a Ryzen 1800x with a 2080ti and I have a 240mm & 280mm in my loop and it works just fine. CPU never gets above 65c and max ive seen my 2080ti is 53c. 

[Stuttgart]

32 minutes ago, Skiiwee29 said:

I have a Ryzen 1800x with a 2080ti and I have a 240mm & 280mm in my loop and it works just fine. CPU never gets above 65c and max ive seen my 2080ti is 53c. 

What are your water temps?

[Skiiwee29]

Just now, Stuttgart said:

What are your water temps?

Couldnt tell you as I dont have a thermal probe to monitor water temps. 

[Stuttgart]

2 minutes ago, Skiiwee29 said:

Couldnt tell you as I dont have a thermal probe to monitor water temps. 

Alright. Well, maybe its time forget water temps.