misc. pump questions
 

First, are the danger den d4, aquaxtreme, and swiftech mcp650 all the same pump? They sure look to be.

I'm looking to replace my current 12V pump, and I'm looking for decent performance but quiet. Of the above pumps, the only one I can find in stock is the danger den d4. That's advertised as quiet, but folks say otherwise. Does it respond well to undervolting? This would be with a conventional variable resistor (e.g. rheostat). I don't mind the sound of gurgling water, but the horrible high-frequency whine of my current pump has got to go. I'm swapping my 120s with yate loons at the moment, so that's my noise floor for comparison. Otherwise, are there other pumps that fit this bill? (don't need tons of flow but this is a pretty restrictive system)

addendum:
fyi, my current desktop chiller (pump plus 2 120 fans) measured ~65 dB with my cheap meter. I'm guessing anything I buy will beat that by a huge margin.

The D4 and MCP650 are the same pump. I don't know about the Aquaxtreme pump.

If you want quiet, get the DDC pump. I know that DangerDen or Swiftech both carry it, although there are probably other retail outlets for it.

Laing D4 = Swiftech MCP650. Noisy.
AquaXtreme 50Z = Swiftech MCP600. Hard to find but is relatively quiet.

Well let me add to this then. I originally dismissed them, but the danger den ddc/mcp350 are starting to look pretty good if I ever want some quiet. I don't have a conventional setup as my chiller/radbox is some distance from my case, i.e. (*gasp*) 10 feet of 3/8 id tubing plus cpu/gpu blocks. Will a second-tier pump cripple under that kind of restriction? I can swap the tubing for 1/2 if I had to, but I'd rather not.

2x DDCs on 3/8 tubing should do fine I'd have thought... One at the radbox end, one towards the PC end.