Does Z440 Z Cooler Fit Z420?

[lastmile77]

I know the Z Coolers from the Z840 will fit a Z820. 

Will the Z Cooler from the Z440 fit the Z420?

Any other combinations of Zx40 Z Coolers and different generations that work?

I know there’s a liquid cooling option for the Z420 (have one in my Z620) and (unreliable) liquid coolers for the Z820. 

[SDH]

I've posted a bunch of times here on this issue. The answer is yes.

It turns out that the stainless steel heatsink mounting system for the Zx20, the Zx40, and the Z4 G4 are all the same. It is the pinout beneath the mounting system that changes from generation to generation of these specific HP workstations, to accommodate the evolving processors. I don't know about the Zx G5 generation yet.

I've been using the "Performance" Z440 heatsink in our souped up Z420 and single-processor Z620 builds for years now, with never an issue. That has almost exactly double the aluminum alloy fin cooling surface area than the stock Z420/Z620 heatsinks, plus it has 4 large-diameter cooling tubes vs 3 smaller-diameter cooling tubes used in the stock heatsinks. Same idea but even better if you happened to have one of the rare and expensive Z440 HP "Vapor" coolers. Both of those still fit perfectly beneath the Z440 active memory cooling saddle, and they also fit perfectly under the Z420 and single-processor Z620 active memory cooling saddles.

HP even has a kit for the Z4 G4 that includes one of those Z440 double-cooling-capacity heatsinks (not a Vapor one) plus a special HP fan wiring adapter demanded by the motherboard if it sees a processor of 145W max TDP or higher. The stock heatsink/fan in a Z4 G4 looks similar to the Z440 one but is smaller with only 3 heat tubes.

Fan plug end: The Z420/Z620 motherboards have a 5-pin CPU heatsink header but the Z440/Z640 have a 6-pin header. You don't have to modify the double-cooling-capacity Z440 heatsink's white 6-hole plug to use it in a Zx20. You just hang hole #6 out in space (about 1/8"... no issue) because the first 5 holes are what are needed to be connected onto a 5-pin header. It fits nicely that way and works perfectly. The wiring is for pins 1-6 is ground, +12VDC, RPM sense (tacho) signal from rotor out to motherboard, PWM control signal from motherboard back to rotor, ground jumper from ground pin 1 to pin 5, continuation of same ground jumper from pin 5 to pin 6.

The HP wiring adapter mentioned above for a Z4 G4 provides pin 5 an RPM sense jumper from pin 3 instead of a ground jumper from pin 1. What the motherboard sees via the trace from pin 5 tells it whether a "Performance" heatsink is attached versus a "Premium" heatsink/liquid cooler.

Took a while to figure all that out. I'd personally not search out a Vapor cooler (but would use one if I had a box of spares). That Z440 cooler has such a high cooling capacity that it is my one-size-fits-all now, and they're only about 15.00-20.00 USD recycled off eBay.

[lastmile77]

Thanks. I started this thread from my phone, sat down at my desktop, saw I had an email notification that you replied, went to a browser tab that already had a forum page open, signed in, and saw... I'd already read a thread, maybe the first thread, about the Z440 passive cooler working in the Z420!

Must have read it too late at night.

I'm running a Z620 with a E5-1660 v2 and Z420 liquid cooler as my main PC. I've posted about it on here before and appreciate all the help I got with questions on coming up with that config. I played around with overclocking when I first set it up but for my needs its been fine at stock speed since then - doesn't mean I don't keep thinking about these workstations and overclocking every time I come across mention of it!

The Z620 has a GTX 2080 Ti with a blower fan in it. I was using it for some crypto mining years ago and was going for cooling of the graphics card over quiet. Now I'm done with that and haven't even been gaming much. I have a Z420 I've never done anything with and a few Z220 SFFs that I've fitted out as low end i5, i7, or Xeon (though typically on the high end for what a Z220 can handle) PCs for relatives.

Thinking about configuring one of the remaining Z220 SFFs as a quiet, less power-hungry computer for general use reminded me of the Z420 and the possibility of passive cooling.

I actually have two passive coolers for the Z840 that I intended to put into a Z820. I've got everything I need to put that system together but I've waited so long to do it that I'm starting to look at Z840s and Z4s. But, what got me back to looking into these workstations was building a small one, not a massive Z8xx.