A bottom mounted cooling solution is best for the Dragonboard 410c due to layout and top-side interference shield with air gap. This will work for all current and future Dragonboards that follow the same 96boards CE spec. Here's a summarization of what you need to do:
Required Items
- A drill with a 3/32″ drill bit (or a drill press)
- 4x 4-40 PHILLIPS MACHINE SCREWS - These are self-tapping screws
- 4x 4MM M3 SPACERS
- 1x THERMAL PAD
- 1x ALUMINUM HEATSINK 2.0" WIDTH. Order 4" in length and specify 3.3" actual size (I went with 3.5" to allow my self room for errors since I didn't have a drill press at the time).
Drilling
Place your Dragonboard on top of the heatsink, mark the locations of the 4 mounting holes, drill all four holes 3/32″ diameter. If you have a drill press, use that. Use WD-40 or cutting oil.
Tapping (threading)
First a note about taping holes in any metal. You cannot just drive the tap into the hole, it will break and you won’t be able to get it out. The tapping operation ALWAYS is done in stages:
- Drive forward about 2/3 of a turn,
- Then back about ½ turn, then forward 2/3.
- Repeat until you have done about 2 full turns then
- Back the tap all the way out,
- Then back in to where you left off.
- Repeat the above steps until you have finished tapping the hole.
- Always tap holes by hand and do not apply too much force to the tap.
Heatsink Installation
Place the thermal pad onto the 410c over the gold square on the bottom, place the 4 standoffs onto the heatsink over each tapped hole, place the 410c over the standoffs, and install the four screws. Since the standoffs are 4mm tall, and the thermal pad is 5mm tall it will get crushed 1mm and make good thermal contact.
References
Results
Before installation, the following would stutter or drop frames after only 10 minutes of running:
ePSXe: Playstation Emulator - Tekken 3
Mega 64: Nintendo 64 Emulator - Super Mario 64
reicast: Dreamcast Emulator - Soul Calibur
reicast: Dreamcast Emulator - Sonic Adventure 2
reicast: Dreamcast Emulator - Marvel vs Capcom 2
Plex: - 1080p stream LAN
Kodi: - 1080p stream stream internet
I ran Trepn Profiler immediately after each session and noticed a drop to 800MHz on all 4 cores and actually teetering between 800MHz and 500Mhz if I'm seeing it right (.8/.5). Very hot to the touch.
I then started on drilling my heatsink with the recommended 3/32 bit and WD-40. Hammered guide holes first using a hole bit tip. My actual drill bit broke on the last hole luckily right after it drilled all the way through. I did this without a press so some holes were at a slight angle but didn't affect the end result. I put my drill in driver mode and manually drove the screws in since they were self-tapping. The thermal pad made good contact and slightly squishes between the board and heatsink.
I then ran the same tests listed above for 10 to 15 minutes each and noticed that the board and heatsink only gets slightly warm on a load this time around so it's doing a great of job of wicking heat away. After each test I immediately ran Trepn profiler and it showed all 4 cores happily humming along at 1.2GHz, teetering between 1.21 and 1.0GHz. The extra 400MHz is immediately noticeable as all tests displayed no signs of stuttering or slow down.
