CM3+ Support for Slice Boxes

**chewitt** · January 28, 2019 at 5:17 PM Official Post

Good news for Slice users .. especially those still with the original CM card: Compute Module 3+ on sale now from $25 - Raspberry Pi

I swapped email with Gordon at the Pi Foundation (one of the Slice designers) this afternoon and he confirms that CM3+ is compatible. Install an LE 9.0 image to use the correct firmware.

okichatan · February 9, 2019 at 6:00 AM

Two questions before I take a plunge from someone who still has the CM1:

1) CM3+ eMMC Flash size: Which one is needed or best?

2) Heat Sink ? I remember lots of discussions and trials on the now-defunct slice forum and in this forum. How hard will this be to figure out or is there a good, safe solution ?

Thanks!

**chewitt** · February 9, 2019 at 6:18 AM Official Post

8GB is the normal minimum we quote for any Kodi install (hence the previous CM1/CM3 with 4GB are limiting) but 16GB is probably a better size to have headroom unless you want to experiment with retro gaming or docker in which case the 32GB card might be attractive (and only $5 more).

As the Slice has a solid metal case a heatsink that achieves contact can conduct more heat away, but there's never been an official heatsink that does this - only homebrew designs that users created for themselves, and the extremely exact dimensions required probably need adjusting for the newer chip design. So the easier option is to get the normal stick-on RPi heatsinks and use those. The result is not as efficient, but it's still an improvement on having no heatsink(s) at all, and you can get them from any Pi reseller for $1.50.

g7ruh · February 9, 2019 at 9:22 AM

Quote from okichatan

Heat Sink ? I remember lots of discussions and trials on the now-defunct slice forum and in this forum

okichatan

as chewitt says it needs a bit of work and the CM3+ will need a slightly thinner heatsink (fatter CPU because of the silver top). The easy solution is as chewitt suggests, get a stick-on one. I found that it still did not really remove enough heat, especially when playing video, so I adopted the DIY approach. While the measurement of the sink needs to be fairly accurate, there is a slight bit of "give" if you press on the CPU so there is a small amount of lattitude when making one.

There were a lot of different designs using bits of copper, I recall one was using buss-bar from a consumer distribution unit.

I used a copper core from an old PC CPU cooler and while not the best at heat transfer, using an aluminium plate, fixing it to the case with epoxy resin glue and letting it sit on the CPU with some heatsink compound works fine. The combination of Cu and Al gave "just the right" size to bridge the gap. The plate is fixed so it prevents the sink being dislodged and doing damage inside.

I attach a picture of the parts. The kaptan tape was used to position the sink and the heatsink compound was used to check contact with the CPU before finalising the design. You can use heatsink compound to help measure the gap, when it transfers to the case or CPU you have it "just right".

I hope that gives you an idea of how to do it.

Roger

rmoody · February 10, 2019 at 3:27 PM

Hello!

Just got the CM3+, installed it in my Slice, plugged it in and nothing.

Using the power supply that originally came with the Slice.

Using USB port connected to my laptop running Ubuntu I can see my hard drive and write to it, but I am not seeing the eMMC storage on the CM3+.

Put the old CM3 back in, works, updated to version 9 (I've not used this for quite some time since it was replaced with a NUC).

Back to the CM+ and no go. Any suggestions? Tips?

Thanks in advance!

Update:

Figured it out. I did this thing called "reading the directions".

Started here:

Flashing the Compute Module eMMC - Raspberry Pi Documentation

Followed instructions for Linux. Connected USB first, then power cable to get the internal storage to appear.

Then to here:

Installation of LibreELEC [LibreELEC.wiki]

Again, followed the Linux instructions.

Unplugged everything, connected to TV and powered up. Everything came up normally.

Hope this helps someone else that gets stuck after so long without touching the thing.

Added it to my home Wiki so I can reference it in the future :).

g7ruh · February 11, 2019 at 8:20 AM

Quote from rmoody

Figured it out. I did this thing called "reading the directions".

Well done, when all else failes nothing beats RTFM as a measure of last resort

okichatan · March 21, 2019 at 11:16 AM

OK - I finally got my CM3+! (8GB was all that was in stock at the retailer I used) Installed easily and was able to follow instructions to install the CM3 slice version on the eMMC. I probably could have backed up my settings, libraries, add-ons, etc. but in my case it was easy enough to just start from scratch.

Now for the heatsink: Locally, I found a small, fairly lightweight, copper heat sink (20x20x6 mm). With just that guy, the max temp (gputemp / cputemp) I’ve reached by just playing videos is about 52°C. While playing video AND updating a large library over the LAN, the temp leveled out at 60°C.

From what I read at the pi site: “...the CM3+ has better thermal behaviour under load. It has more thermal mass and can draw heat away from the processor faster than CM3. … longer sustained operation under heavy load before the processor hits 80°C and begins to reduce its clock speed.”

My 52-60°C seems like a reasonable enough range?