I found in the street 4 Optiplex 780, 1 optiplex 380 and a small tower based on a Gigabyte LG1155 I3 CPU.
This is the modding of one of the optiplex.
For this one, I took the "best" working parts from all the 4 Optiplex 780. It required a LOT of cleaning. Those things were filthy.
The paint job was basic, I cut a window in the side panel, cut some non-air-flow-friendly pieces of metal in the case, and trew in a few better parts:
- Intel Core 2 Quad Q9550. I didn't have a Q9650 readily available in my spare parts and don't plan to spend 60 bucks on a used one.
- A better heatsink from a more recent Optiplex.
- A Noctua NF-R8 redux-1800 PWM to replace the front CPU fan. This one when running at max speed is almost as efficient as the original Dell, and males MUCH less noise. It required some soldering to adapt the 4 pin PWM connector to the stupid Dell 5 pins proprietary connector. The speed is also sometimes messing with the mainboard sensor, giving the infamous "press F1 to continue message". It happens very often in S1 resume mode, and almost never in S3 resume mode.
- I Removed the HDD bracket and the fan that goes with it. That triggers a very annoying alert during post: I first fixed it by picking the front fan RPm signal, and when I added teh side exhaust fan, I picked up its RPM signal.
- I added a 250GB SSD and a 2TB HDD that fit perfectly behind the useless floppy bay.
- I added a GT1030 low profile graphic card. Perfect for 4K display. And it can sorta play. I'm not into PC gaming anyway.
- I kept 2 sticks of 4GB DDR3 that I salvaged from the other PCs, and added 2 sticks of 4GB for a total of 16GB.
- I added some fancy cheap RGB kits.
- I swapped the DVD player for a BR player / recorder.
- I tried to make the cables a little more air flow friendly, but in such a small case, you can't expect any miracle.
I tried to replace the PSU fan, but it turns out that silent is not effciient enough to cool it. The airflow is quite bad and I'm considering options to improves that. Cool air comes from the front, cools the CPU, and is sucked by the PSU that is therefore using warm/hot air to cool itself and extract that hot air from the case.
Putting an extraction fan in the side panel would be ugly, I don't like this option.
There is a metal grid on the read: I could maken acrylic fan enclosure that would work parrallel to the mainboard.
Windows 10 runs smoothly, playing 4k BR and movies is flawless, and even working in Lightroom and Photoshop is surprisingly fast.
There are not much more upgrades possible for this little computer. The 3Ghz Q96650 wouldn't improve performances a lot, SATA is 3GB/s, and max memory and memory speed is allready reached. I will keep it that way and just try to make it more silent.
Almost forgot: a very annoying coil whining was fixed by turning off C states in the bios.
UPDATE: I eventually decided to mod the front panel, cutting the small plastic blades that made an annoying noise when air sucked by the frotn fan passed trough. I added a metal mesh, and surprisingly got very impressive temperatures drop (4 to 5°C).
Then I decided to add an exhaust fan in the side panel to get rid of all the hot air inside more efficiently. It's a 12V 12cm fan with blue LEDs. I give him 5v picked on the internal USB connector, i pick up 12V for the LEDs at the HDD fan connector and also send back the fan RPM signal to that connector.
The very low noise even in full load is impressive, as are the temperatures, with a delta ranging from 22°C (room @ 22°C) to 25°C (room @ 29°C).