800 G1 SFF 4790K Cooling

[JC20252025]

I just upgraded to a 4790K CPU in my 800 G1 SFF. As expected, with the stock CPU sooler, it's running hot. I purchased a Noctua NH-l12S, but unfortunately it appears that the HP motherboard uses non-standard hole dimensions for the cooler. 

In order posts, it has been mentioned that a "712960-001 (625257-001)" is sufficiently powerful to cool it. Will that part definitely fit onto the 800 G1 SFF motherboard? Is it more powerful than the stock cooler, P/N 711578-001? Are there any other coolers out there that will fit?

Thanks!

[NonSequitur777]

@JC20252025,

Welcome to our HP Community forum!

There are ways to mod or modify your HP EliteDesk 800 G1 SFF, as these Users showed/blazed the gaming trail: https://www.userbenchmark.com/System/HP-EliteDesk-800-G1-SFF/589.

Here are some helpful YouTube instructional videos in the context of your question: https://www.youtube.com/watch?v=UfIL7x1reDM&t=123s&ab_channel=ServerScience, and: https://www.youtube.com/watch?v=DvNWbDd-ZCQ&ab_channel=ITGGear.

Kind Regards,

NonSequitur777

[JC20252025 · Accepted solution]

I got the Noctua NH-L12S to work!

The screws for the "AMD" installation that came with the mounting kit (Noctua's SecuFirm2 mounting system) fit into the holes already present in the motherboard - the threads are the same. None of the included brackets fit properly. The holes in the included brackets didn't match the holes in the HP motherboard. I was able to drill a 1/8" hole into each of the long AMD brackets included in the kit, to match the distance of the holes. With the brackets pointing the "wrong" direction, the NH-L12S fit perfectly. The pipes from the heatsink did, in fact, clear the RAM without issue. 

It took me a couple of hours to figure out, but ended up being a very minor modification to the brackets once I realized what needed to happen. No need to remove the motherboard, and use the included hardware labeled AMD. 

Temps under full load over an hour-long stress test topped out at 75, degrees C, but mostly hovering around 65-70. Idle temps down at around 35-40. Super quiet. 

If anyone is wanting to use a 4790K in the 800 G1, the NHL12S is DEFINITELY the cooler I'd recommend. 

[JC20252025]

Thank you!

I had looked and looked for videos to help, but couldn't find any that were applicable. Those two videos gave me the idea I needed to figure it out. 

Thank you!

[NonSequitur777]

@JC20252025,

You are welcome!  Glad that we could collaborate finding solutions!

If you could provide some pictures and post them here, that would be awesome!

Kind Regards,

NonSequitur777

[JC20252025]

Yes - I forgot to take pictures after I had the brackets mounted. 
I'll take it apart tomorrow and get some photos for posterity. 

[NonSequitur777]

@JC20252025,

That would be awesome!

Your pictures will without a shadow of a doubt help out other users in the future, who will be grateful you posted them.

Kind Regards,

NonSequitur777

[JC20252025]

I should have taken photos before I mounted the cooler, but these should give you some indication of how I mounted it. 

You'll notice that I drilled an additional hole on each bracket, and that the brackets are inverted, with the bend TOWARDS the processor, not away as the arrows on the bracket would indicate. Worked perfectly.  The photos aren't great, but if you zoom in you can see where I drilled the extra hole. 

[NonSequitur777]

@JC20252025,

Outstanding -thank you for sharing!

And this is exactly what makes upgrading a legacy desktop so much fun!

Kind Regards,

NonSequitur777