Z420 - Problems with liquid cooling system

[SDH · Accepted solution]

I just checked on eBay.... the Z420/Z620 standard heatsink/fan is a "Performance" type using a 92 x 92 x 25 mm fan with the white plug end with 5 holes and the black ground jumper from hole 1 to hole 5.  Those heatsinks (647287-001) are going for as low as 10.00 USD to get the fan with proper wiring from.  Or, you might even be able to just buy one of the Z440 heatsinks (749554-001) with the 6-hole white plug end and hang that far end out in space above the motherboard if there is spare room along that edge.  The Z440 plug end has the standard ground jumper from hole 1 to hole 5, and then an extra ground jumper from hole 5 to hole 6.  So, electronically if that far end is hanging out beyond the end of the motherboard header it would not matter.  I have not tried that but would be the cheapest solution if there is nothing in the way for that little bit of plastic hanging out to hit.  You can snip off the hole 5 to hole 6 jumper wire if you wish.

What HP has done with their CPU heatsink fans is always place a quite high speed fan, and then drop its speed by applying PWM braking to that high speed.  If your PWM fan is pretty slow to begin with then the automatic motherboard braking that is applied will drop its speed even more, below what is ideal.  For example, nice quiet slow Noctua PWM fans go way to slow under this circumstance.

Some processors will throw out a warning if they don't see the "Performance" type of fan wiring.  Yours does not seem to but later if you upgrade processors that may become an issue.  Here is a picture from a Z400 Performance heatsink, and the part number of that heatsink is on the pic.  However, at 10.00 including shipping I'd just go for the Z420/Z620 heatsink noted above to get a more recent fan that way.

[Macrero]

SDH,

thanks a lot for your time and help. 

I am in Spain and shipping cost is a deal killer, but I will buy one. I can get also the original liquid cooler for  a tad more $. 

Truth be told, workstation is working flawless so far, temps are in a more than acceptable range, no hardware related errors and performance is just as expected. Nevertheless, I will buy HP heatsink/fan just in case.

Best,

- Macrero

[SDH]

I was doing a project with a Z420 version 2 today and took a close look at the stock heatsink/fan and the motherboard's 5-pin header for the CPU heatsink fan.  There was no reason physically that the Z440 larger heatsink/fan's plug won't fit perfectly on the Z420's motherboard CPU fan header, with the 6th hole part of the plug projecting just a bit beyond the Z420 fan header, hitting nothing.  The friction of the 5 pins there and the built in ridge by hole #1 will keep that plug snug on the header.

I think all your options are open, and that non-hp heatsink your guys got you sounds just fine.  The cheapest and easiest is to just enjoy what you have now.

Happy to help......