4090 + 7800x3d loop

[mx313]

Hi. I am considering building custom loop for palit 4090 (450 watt tdp) + 7800x3d (~100 watt tdp) with following Alphacool parts:
- Eisblock for gpu
- core 1 lt block for cpu
- 120mm flat reservoir with ddc310 pump
- 2 radiators: hpe-30 280mm and hpe-45 280mm
- GL50 as liquid
- edpm as tubing
Questions:
1. What kind of liquid temp (delta ambient) may I reasonably expect if I run only 4 silent wings 4 140mm fans on radiators (2 fans as push on each radiator) at 750-900 rpm at full load? Please assume there will be no other fans and no airflow restrictions in a m-atx case (consider it an open bench).
2. Assuming I aim for low maintenance and low noise and do not care about liquid temp (as long as it is within safe levels, which I understand is 60 celcius), does using gl50 makes sense instead of e.g. Alphacool Ultra Pure Water?
I understand that gl50 may increase loop temp by 1-3 celcius, but if I can have acceptable liquid temp all year round with 750-900 rpm fans (as outlined above) - that is OK for me. I live in Poland (so no extreme temps in summer).
3. I understand radiators need to be pre-flushed. I also understand gl50 should not be mixed with other solutions. Considering this:
3.1. Would it be ok if I flush the rads with distilled water and then just try to shake the remains of the water from the rads? Or do I need to wait the rads to completely dry inside for several days?
I think I might be overcomplicating this and several drops of distilled water (if they are not shaken out eventuallt) would be ok if the loop is filled with gl50, but want to check.
3.2. Do I also need to flush other components (gpu, cpu blocks, flat reservoir or tubing)?
4. Considering my case (gl50 + 4 fans with 750-900 rpm) would there be practical difference between using edpm or pvc tubing?
I assume that with my background the loop liquid temp may be on a higher end. I have read somewhere on forums that high liquid temp in pvc tubing ultimately results in system being clogged with plasticizers in a couple of years. I have not verified this info and not sure if this is relevant if I would be using gl50. If in my case (potentially high liquid temps) there would be no practical difference between pvc and edpm, I would rather stick with pvc tubing.
5.I understand 120mm flat reservoir could be used with different pumps (d5, apex vpp, ddc310). What version of pump should I consider if I aim for the least noise (both rotor noise and coil whine, if any) although at potentially higher liquid temp?
The loop will not have any restrictions (only a temp sensor, but no filters or flow meters).

Any input would be appreciated.

 

[Eddy]

Hi,

1.
That is impossible to answer. It depends on the quality of the CPU, the thermal paste, the water flow (which depends on the pump setting and the overall setup), the speed of the fans, the ambient temperature and so on. There is no answer to this question that comes close to the truth.

2. Basically, we only use GL50 in servers because this fluid is virtually maintenance-free. Clare fluids such as Ultra Pure have the highest cooling capacity, but as they have no ingredients, algae formation or similar can quickly occur. If you are looking for the lowest possible maintenance, then GL50. It is clearly superior to all other fluids in this respect.

3. Simply rinse it with disinfected water and then simply fill the GL50. The few water residues do not cause any problems. You can safely ignore this problem. These are far too small a quantity and have no relevance.

4. PVC hoses contain plasticizers. These always flush out at some point. You will then see fine white threads or small white dots in the water. Depending on the temperatures, how long the system has been in use and even the amount of sunlight, this may happen after 1 year or only after 2-3 years, but it will happen. When it comes to durability, you can't get around EPDM or TPV hoses. All transparent hoses fall out when it comes to real durability.

5. The Apex is the quietest and most powerful pump. But as always, different people will give you a different answer, as everyone perceives noise differently. For example, I find the DDC pumps annoying because they make a high-pitched sound to which I am very sensitive. Others would say the D5 is louder because it has more of a low tone and other people are more sensitive to it. But in general, the Apex is the quietest. If you decouple the expansion tank and let the pump run at approx. 50% PWM, you shouldn't be able to hear it coming out of the housing at all. And 50% is quite enough.

 

[mx313]

Thanks Eddy. I have purchased everything needed for the loop and hopefully all will arrive before the weekend.
Could you please also clarify regarding Alphacool Leak testing tool. The manual says I should do 0.5 bar pressure to test the loop. However on some forums people write that at 0.5 bar their fittings pop.
I plan to test each component separately with the tool first, and then the whole loop. Is 0.5 bar the safe amount for this exercise? I aill be using exclusively alphacool hf fittings & alphacool edpm tubing.

 

[Eddy]

However on some forums people write that at 0.5 bar their fittings pop.

Every circuit should be able to withstand 0.5 bar. Popping actually only happens with HardTubes. This is because the tolerances for hard tubes can be quite large. This is not a problem with tubes, unless you have bought some really junk. More than 0.5 bar makes no sense, as most pumps can only build up pressure between 0.34 and 0.44 bar at maximum speed. Only our Apex manages 0.48 bar.
The TPV connections have a locking ring and can withstand up to 8 bar. All other components for end customers are tested and designed by us for up to 0.8 bar pressure. This includes expansion tanks, coolers and radiators. However, most components can withstand significantly more than 0.8 bar.