2017 TB MacBook Pro – Temperatures

[themcfly]

Hi everyone,

I just completed my "dream setup" consisting in only hooking up a single Thunderbolt to connect charge/display/ethernet/audio everytime I get home, on my 2017 15" TB MBP with the 560. I'm using a CalDigit Thunderbolt Station 3. I'm experiencing far higher temperatures and fans revving while docked with light usage on a 2560x1440 monitor compared to undocked on internal display, which is in fact pushing 1920x1200 HiDpi (3X the pixels + downscaling) with moderate load on the CPU.

For the purpose of gathering temperatures, I setup a 1920x1080 high quality MKV video playing on VLC on the desktop. Every app closed, just iStat Menus running to get a reading of the temperatures. Fans were locked down to slowest speed through iStat, so I can just get a reading of the temperatures after 5 minutes of stabilization time.

• Internal monitor, charging through Apple stock charger: 57C°
• Internal monitor, charging through Thunderbolt Station 3: 65C° (+8C°)
• External monitor, charging through Thunderbolt Station 3 with internal monitor left open : 70C° (+13C°)
• External monitor, charging through Thunderbolt Station 3 in clamshell mode: 67C° (+10C°)

So, it seems that just connecting the Thunderbolt dock makes some other chip heat up inside the MacBook, that probably uses the same cooling system of CPU/GPU. This chip/area is probably disabled when using it to charge only or using USB-C Accessories. In other readings, I can see the "Thunderbolt Left Proximity" spike from 40C° to 60C° just connecting the Thunderbolt Station 3.

Interesting note: I can see that spike in temperature even if I just connect the Thunderbolt Station 3 with the stock Apple USB-C charging cable: Sierra detects that there is a Thunderbolt 3 peripheral but can't use it and asks for a Thunderbolt cable instead, but the area definitely still activates and heats up.

Is any of you guys experiencing the same issue? Thanks in advance.

 

[PBG4 Dude]

You're probably activating the thunderbolt 3 (Alpine Ridge?) chipset. TB3 won't be part of the actual CPU until Coffeelake I believe (could be wrong).

 

[Patcell]

You're probably activating the thunderbolt 3 (Alpine Ridge?) chipset. TB3 won't be part of the actual CPU until Coffeelake I believe (could be wrong).

This is correct. The Intel Thunderbolt 3 controller (code name: Alpine Ridge) activates when a Thunderbolt peripheral is attached. I had never though of it as a potential cause of increased temperatures, but it makes logical sense.

I the same machine as you (2017 15" w/ RP 560) connected to an OWC Thunderbolt 2 dock and charging via the stock charger (via a separate port). The TB2 dock connects to an Dell P2415q 4k display set to "looks like 2560x1440 (rendering 5120x2880 and downsampling to 3840x2160). Connected to the dock and charger in clamshell mode, my computer (CPU die via iStat Menus) idles between 48C-52C - doing nothing in a room with ambient temperature 22C (about 72F). As I mentioned, I hadn't noticed this, but the Thunderbolt left proximity (side connected to TB2 dock) jumps to 48C when connected to the dock, which probably contributes to higher CPU temp. My temps quickly rise when I add any load to the system. Even a 1440p YouTube video will push the CPU die to 60C+ easily.

What are your idle temps connected to your docking setup? What is the approximate ambient temperature in the room? I have been wondering about the temps as well... I'd like to compare our systems.

 

[themcfly]

The temperatures I wrote in the OP were all referring to CPU PECI (I always had that as the standard CPU reading in iStat, sort of like a average value of all cores). For me it idles at 54-55C° with the Thunderbolt Station 3 connected (see attached readings of all temperatures), room temperature is 28C°. You can see that Thunderbolt Left Proximity is hotter than the Right, which is where it is connected. Switching sides inverts the two temperatures.

I'm just wondering if it's worth it. Idling with no Thunderbolt activated averages 10-12C° less. Thunderbolt ha surely much bigger potential, but I can dock with an USB-C dongle with HDMI/Audio/Ethernet + an additional stock charger in pass-through and get the same result. I tried some USB-C docks but either they could not reach Gbps speed as they promised or they couldn't charge a 85W, and still I would have to buy an additional charger to keep docked.

I went with the TS3 because it "included" a 85W charger and has true Gbps speed, and seemed the most functional and polished solution, but the fans revving up with little to no usage bother me a little. On the other side it works perfectly with everything attached, monitor is rock solid, ethernet is truly Gbps, while reading reviews of other docks solution (like the OWC USB-C) is not that perfect of an experience, and also doesn't charge over 60W.