A liquid cooling system might be easier than changing cases.  https://www.dell.com/community/Precision-Fixed-Workstations/Dell-Precision-3630-liquid-cooling-with-Corsair-H60/m-p/7411998 

Thanks you for your case, I think I prefer to use Noctua NH-D15 and change a mATX case after warranty if worked.

Not as easy as it looks, but possible.  Keep in mind of proprietary power button wiring.

Ports on the back panel are attached to the MB.  So the mATX case may need cutting in the rear.

A couple of things you might find - 1. Might be somebody more knowledgeable in this forum at case transfers than I am.  2. YouTube videos.

I've done rebuilds and mods, but not case transfers.

Hi @redxps630 - By any chance do you have case transfer knowledge for a Precision 3650 to mATX?

Thanks for your tips.

My Lian Li case has been working for eight or nine years change from an XPS8300.

Yes, I think that front panel and DVD tray on Precision 3650 should be connected to installation. But back panel maybe not match other case. Is the MB's screw suit for mATX or not? I need to do more research...

Dell, being quite proprietary, makes it likely screw holes won't line up.

@speedstep is another one that knows about case transfers and wiring.  Speedstep would have a better idea about transferring 3650 to mATX case. 

@alee001 

@bradthetechnut 

Beyond the proprietary cables and sensors the motherboard is not standard.  Hasn't been since the Precision T1600 T1700 series.  The 8940, G5, 7080 goes further by removing front panel and making that part of the motherboard.  There is also no more I/O shield and sometimes backplate as these are part of the case.  Where the IO Shield goes there is a sticker that makes it look like nothing changed. After the 3620 they started making NON STANDARD fan connectors and power buttons and USB headers to be totally proprietary.  They do not want you to re use their case or move your system to a new case.  You can move cpu, ram, hdd, ssd, and some fans but the motherboard is not happening which makes upgrading to something new more work than its worth.  I get pm's all the time with people demanding that I document the proprietary connections and connectors that are non standard.

Older models are more easily converted and will run Windows 11 in un supported mode.  Not supported does not mean not working.

TPM and Secure boot are OPTIONAL when you use Rufus 3 to make a special installer. Pentium D 915 is as low as you can go because there is NO 32 bit windows 11 installer.

Systems like the T1700 with TPM 1.2 and secure boot are easier but all models including Optiplex GX620 with Pentium D  915 to 960 will work its just not a water chicken 1 reboot 20 second install.

Rufus 3.17p  is the recommended solution for very old models.

Add Windows 11 "Extended" installation support (removes TPM/Secure Boot/RAM requirements)

The Mosetup method works fine for newer than 2012 models with TPM 1.2

The reason to recommend T1700 is as follows.

It has Secure boot.

It has TPM 1.2

It can support 32 gigs of ram

It supports INTEL XEON processors 4th gen Haswell that do not have INTEL Graphics and therefore are not a security risk.

I am sure that Retail Windows 10 and OEM windows 10 will go away once windows 11 is released.

Which is why you should buy an OEM WIN10 DVD or Retail Copy of WIN10 pro USB Flash drive NOW because in October those will go away forever.

OEM Windows 10 Recovery Forever DVD $15

Windows 10 Pro Retail USB Flash Drive $199

ISO Downloads of 10 will go away in October 2025.

The latest windows 10 ISO  (FREE) should also be downloaded NOW and installed via the media tool.

Saving the 21H1 ISO to an external hard drive that is only on to backup data is a good Free strategy to keep using windows 10 even after its gone.

Media tool
https://go.microsoft.com/fwlink/?LinkId=691209

Both Whynot Win11 and PCHealth Check say NO for CPU and NO for TPM on my T1700 with latest bios.

There is no INTEL PTT to switch to which would make the T1700 more likely to get support.

Start flighting now by running Insider Preview builds on your devices to use with the latest SDKs and to see what's next for Windows.

https://aka.ms/GetPCHealthCheckApp

Download WhyNotWin11 on Github

Older Dell is gaming PC?

https://www.youtube.com/watch?v=56MgVgnRBSs

@bradthetechnut 

Recommended a T3620  for a client and added a Quadro K2200

Windows 11 works with this model but is not supported.  That said with the WIN8 BIOS key on this model there was no cost to upgrade to 11 PRO.

https://www.userbenchmark.com/UserRun/50653658

Works fine with the stock PSU  290W but I upgraded it to the optional 365W psu so that a quadro RTX 4000 can be added if they need more GPU horsepower.

The RTX 4000 like the GT1030 from a while ago is a good buy because it fits and doesnt require a huge power supply.

T3620 like the T1700 has lots of expansion options that other models don't have.

If you worry about the power supply you can always replace it with an EVGA 700BR for a very reasonable price.  This unit using DDR4 means you can use the base model and upgrade CPU and motherboard but use upgraded ram and power supply in a newer model if you buy ram that works with newer processors.

T1700 and T3620 are fine for VR workstation as well as Cad etc.   Games also work fine on the quadro even though its not designed for that. Its not a crazy expensive card and it works fine.

https://www.youtube.com/watch?v=hqIol8IWe8o

https://www.youtube.com/watch?v=VccHOrN5TXE

T3620 Models

Quadro K2200

If not change Dell case, Is the liquid cooler better than Dell cooler?

P.S. I always run job with 2.5 hr under 99% CPU with 90 degree.