You'd be crazy to replace the PA120.3 for any other rad. It's still one of the better performers and the only 'negatives' are the 3/8" ports which still have adapters available and the 25mm fan spacing which makes it harder to mount in a case. The only reason I switched from a Phobya 400 to a D5 was for the reduced noise levels, nothing else.
Yup, a good rad but I figured the triple 360 might be even better. Thing is I dunt actually need it. Nor do I need a new pump cos the EK 4.0 is pretty quiet. Quiet but not silent. Can hear a low rumble/grind but not loud. Tempted to go D5 to blast the coolant around what is a long loop but it's not a necessity. I think my full load CPU temp could be lower and I suspect the long loop is responsible but I like having rad by open window.
In that case I'd also think about a Swiftech 35X which has the advantage of PWM control of pump speed. The majority of the time when your system is under low loads you can run it a slow speeds and use PWM to crank it up to full speed under high loads. The 35X is definitely quieter than an EK 4.0, a bit louder (at full speed) than a D5 or 355 but extremely quiet at slow speeds. However if to you an EK 4.0 is quiet then you probably won't hear a D5, 35X or 355.
I just tested out a Swiftech MCP355. At full load its very quiet. A slight whine if you come within about 2 feet of it. I placed some sound dampening material I had spare on the top of the DVD drive that sits below it, and now its utterly silent. The only way I can tell its on by looking at the water in my res.
But there is no point in me buying a pump with similar or lower head pressure. At least the D5 strong is significantly higher spec. The noise I have from my DCP 4 is very low level. I sit 2 metres from it and it's very quiet at full speed so the noise is no reason for me to change. The pump that most interests me is the EK strong D5 at 24v with 1800lph or the koolance strong with 5.9 head.
I have the DCP 4.0 as well. I returned my first one because I had the same grinding noise that wasn't air bubbles; my replacement was dead quiet. I run mine at 9v anyway for total quiet. Vibration levels drop incredibly from 12v to 9v. PS the EK DCP is a rebranded Jingway series pump. They sell this model rebranded by 3 or 4 other companies.
Aha. You see I forgot the title of my own thread and thus the truth emerges that this is really a selfish thread to find out which is the most powerful and quietest pump... It's the same grinding you get with the Eheim's as well. It uses the same design doesn't it. I've never tried mine at 9v. Guess I could wire it to a variable voltage PSU for testing.
Update: So last week I was twice at checkout of EK shop with D5 strong in basket. Both times I came close to buying and both times cancelled. If that pump had a tacho sense line I might have bought. I thought I'd save some money so I bought a second EK DCP 4.0. Plumbed it in and the noise was horrendous! Loadsa tiny bubbles circulating. After running some hours, it began to quieten down, a day later it was even quieter and now both pumps are very quiet. Cooling performance increased significantly. CPU is cooler at idle and load. Almost 10c off at full load. Advantage is dual pumps for safety redundant feature and the pumps have tacho line so can monitor pump speed.
Extreme pumpness.. I've long had a fantasy about connecting waterblock to domestic cold tap and blasting the cpu with high pressure cold water. Probably easier just to buy an aquarium chiller. Feels like cheating somehow though.
I've got a GT Stealth rad that now looks like a balloon after I put mains water through it in a simple loop. Doesn't leak though and performance is apparently unaffected.
Many years ago I had my DD Maze 3-1 waterblock with a 130w peltier sandwiched between it. Connected to cold tap and powered at 15v the waterblock got a thick layer of ice on it within minutes.
