starfireprime Posted February 2, 2015 Report Share Posted February 2, 2015 I have Flirc's Pi case for my Model B+ and really love the product. I've noticed that for the newly announced Pi 2, the Broadcom chip appears slightly larger, although in the same location on the board. Any thoughts on thermal issues if the Pi Case's aluminum heat sink only covers a majority, but not the entire surface of the chip? I'm guessing no, but I thought I'd ask. :) 1 Quote Link to comment Share on other sites More sharing options...
ChristTheGreat Posted February 2, 2015 Report Share Posted February 2, 2015 (edited) I would say no, it would still work as I guess, the biggest heat will be in the middle and the case will dissipate heat. I think it will cover at least 75-80% of the chip? I don't think it would cause any problem with the PI 2. edit: well, if the chip is locate at the same place, but longer (no in the middle) I'm not sure now xD PI2 B+ I hope they are the same height at least! Edited February 2, 2015 by ChristTheGreat Quote Link to comment Share on other sites More sharing options...
yawor Posted February 2, 2015 Report Share Posted February 2, 2015 The biggest difference in layout between RPi B+ and RPi 2.0 B is not the CPU placement but the RAM placement. On pre-2.0 boards RAM is mounted on top of the CPU. On 2.0 board the RAM is on the other side of the board. Because of that the CPU on the 2.0 board is thinner than the CPU+RAM on pre-2.0 boards. I don't know how the thermal pad looks in the Flirc RPi case (I don't have one yet as I don't have RPi B+) but there is a risk that it won't even touch the CPU because of its thickness rather than the position or its size. 1 Quote Link to comment Share on other sites More sharing options...
jason Posted February 2, 2015 Report Share Posted February 2, 2015 There won't be any issues. We tested a few weeks ago. While the chip is a little bigger, the heat sink will do as its intended. The hot spot won't be at the end of the chip. 1 Quote Link to comment Share on other sites More sharing options...
ChristTheGreat Posted February 2, 2015 Report Share Posted February 2, 2015 thanks for the confirmation! very appreciated! Quote Link to comment Share on other sites More sharing options...
starfireprime Posted February 2, 2015 Author Report Share Posted February 2, 2015 There won't be any issues. We tested a few weeks ago. While the chip is a little bigger, the heat sink will do as its intended. The hot spot won't be at the end of the chip. Thanks Jason. Any thoughts/observations on yawor's comment as to the height of the CPU off of the board and the thickness of the thermal pad? I don't recall the thickness of the pad in the case that I already received. Quote Link to comment Share on other sites More sharing options...
ImCoKeMaN Posted February 2, 2015 Report Share Posted February 2, 2015 Awesome, I have a feeling that my Flirc case might make it to the new Rpi 2 I just ordered, or do I need another case? wouldn't want the B+ to be naked.... hmm decisions decisions. This was definitely one of the first things I looked up with the announcement, great news, glad you got to test it already too! Quote Link to comment Share on other sites More sharing options...
yawor Posted February 3, 2015 Report Share Posted February 3, 2015 There won't be any issues. We tested a few weeks ago. While the chip is a little bigger, the heat sink will do as its intended. The hot spot won't be at the end of the chip. Is the new CPU on the 2.0 board actually thicker than the CPU alone on the 1.x? Because with RAM removed from the top of the CPU and moved to the other side of the board I was afraid that the thermal pad might float a 1-2 mm above the CPU instead of touching it. Anyway great news that you've tested and it fits :). Quote Link to comment Share on other sites More sharing options...
DocG Posted February 4, 2015 Report Share Posted February 4, 2015 (edited) Some data. The chip on the Pi 2 is only about 0.2mm less in height than the chip on the Pi. It isn't, however, in the same place. It's slightly off to the left. The left edge of the Pi 2 chip is about 3mm out of the edge of the Pi chip, and subsequently, the heatsink. It actually does hang over on the right now. By how much cooling is affected all depends on what exactly is on those leftmost 3mm. It is, however, an extreme bother to people with OCD, because it simply doesn't fit from a purely visual aspect. Saying that, will we see a revision of the Flirc case to accomodate the exact placement of the Pi 2 chip? Edited February 4, 2015 by DocG Quote Link to comment Share on other sites More sharing options...
starfireprime Posted February 10, 2015 Author Report Share Posted February 10, 2015 (edited) Just a follow up - I received my Pi 2 today and already had my Flirc case. The board fits fine in the case, but it did not appear as if the thermal pad made contact with the heatsink post at all. The board easily rocked out of the case when I turned it on its side suggesting that there was not adhesion to the pad at all. Also as DocG noted, the post is noticeably off center. For now, I removed the pad an am just running the board in the case. EDIT: Without the thermal pad contact, temps run a little hotter (as one might expect with less air circulation and no direct thermal transfer). My unscientific measurements: In Case Alone (68F room) Idle 40-42C 38C 1 busy core 45C 44C 2 50C 49C 3 55C 54C 4 60C 57.5C Edited February 10, 2015 by starfireprime 1 Quote Link to comment Share on other sites More sharing options...
krnage Posted February 16, 2015 Report Share Posted February 16, 2015 are you able to measure what the gap is somehow? Looking to get a Flirc case (once they come into stock) and a thicker thermal pad they have options of EK Thermal Pad .5mm 1mm 1.5mm or will there be a pi2 case in the future? Quote Link to comment Share on other sites More sharing options...
jaymillerSR Posted February 16, 2015 Report Share Posted February 16, 2015 I'm curious the this as well. How much of a bigger size thermal pad is needed? Quote Link to comment Share on other sites More sharing options...
DocG Posted February 17, 2015 Report Share Posted February 17, 2015 I doubt you'll be able to measure the gap, but if you go one up, i.e. 0.5mm from whatever the supplied pad is you should be good. You'd probably do well to not put the pad in the center of the post, but place it so that it covers more of the chip. Quote Link to comment Share on other sites More sharing options...
Lukeroge Posted February 18, 2015 Report Share Posted February 18, 2015 (edited) I doubt you'll be able to measure the gap, but if you go one up, i.e. 0.5mm from whatever the supplied pad is you should be good. You'd probably do well to not put the pad in the center of the post, but place it so that it covers more of the chip. The problem with a thicker thermal pad is that it loses a lot of effectiveness, and starts to become more of an insulator then a conductor of heat. Thermal pads don't actually help transfer heat amazingly well, the best solution would be two perfectly flat pieces of metal touching directly, but that's not possible, so we use thermal pads/paste. Edited February 18, 2015 by Lukeroge Quote Link to comment Share on other sites More sharing options...
DocG Posted February 18, 2015 Report Share Posted February 18, 2015 I was just modding a Flirc case and I almost got rid of the heatsink post entirely. Might still do that, as it might actually work better with a separate heatsink. Quote Link to comment Share on other sites More sharing options...
yawor Posted February 18, 2015 Report Share Posted February 18, 2015 The problem with a thicker thermal pad is that it loses a lot of effectiveness, and starts to become more of an insulator then a conductor of heat. Thermal pads don't actually help transfer heat amazingly well, the best solution would be two perfectly flat pieces of metal touching directly, but that's not possible, so we use thermal pads/paste. I think that it's still a better conductor than the air itself :). I think that gluing (using a thermal conductive glue of course) a thin flat piece of copper on the heat sink post may be doable. Then replace thermal pad with some good thermal paste like Silver Arctic 5. Quote Link to comment Share on other sites More sharing options...
Lukeroge Posted February 20, 2015 Report Share Posted February 20, 2015 (edited) I think that it's still a better conductor than the air itself :). I think that gluing (using a thermal conductive glue of course) a thin flat piece of copper on the heat sink post may be doable. Then replace thermal pad with some good thermal paste like Silver Arctic 5. Oh yeah, it's better than air for sure, I was just saying that in general, thermal pads are worse than direct contact (with paste). Edited February 20, 2015 by Lukeroge Quote Link to comment Share on other sites More sharing options...
Whiznot Posted February 24, 2015 Report Share Posted February 24, 2015 I have a new Flirc case but don't have a RPi 2 yet. If I find that the case heat sink doesn't make contact I plan to adhere aluminum shims to the heat sink to make it work. It is easy to cut aluminum shims from a beer can. Quote Link to comment Share on other sites More sharing options...
yawor Posted February 24, 2015 Report Share Posted February 24, 2015 Whiznot this is not a good idea. You would need to glue together multiple layers because cans are made from really thin sheet of metal. This aluminum-glue "sandwich" would probably be no better than a foam thermal pad. It would be best to find a sheet of copper of proper thickness. I don't know how thick it would need to be because I don't have the case nor RPi2 myself yet to do some measures. It would be best if the sheet is thick enough that it actually touches the CPU so you can use some good thermal paste (for example silver based like Silver Arctic 5) between the CPU and the copper pad. Quote Link to comment Share on other sites More sharing options...
DocG Posted February 24, 2015 Report Share Posted February 24, 2015 (edited) If I was serious about using the heatsink I'd start by sanding back the coating to expose the bare aluminium, then I'd pretty much do what yawor was saying. As a side note, I thought the Flirc case looked pretty good, but then I took one and sanded back the outer coating. What a difference! Everything just looks so much better in brushed aluminium. :) [Edit] Did a slight variation with using a thicker thermal pad (http://oi62.tinypic.com/equrmo.jpg), and at least for my case can confirm that despite having slightly sanded back the post a 1.5 mm pad bridges the gap between heatsink post and processor. Edited February 26, 2015 by DocG Quote Link to comment Share on other sites More sharing options...
starfireprime Posted February 26, 2015 Author Report Share Posted February 26, 2015 (edited) @DocG - thanks. I'll try a 1.5mm pad and some stress tests to see how it works! Edit: Picked up a T-Flex 15mmx15mmx1.5mm pad off of ebay. It fully covered the cpu. I sanded off the paint on the post to expose the aluminum and gave it a shot. Although the pad may have been touching the post slightly, I was unconvinced that there was good contact since the board still rocked out pretty easily. So I took a rotary tool to the four screw posts to shorten then up a bit, reinstalled the board and was reasonably pleased there was contact between the pad and the post. Some stress numbers Ambient ~ 64F ~ 18C Idle 29.3C 1 thread 32.6C 2 34.7C 3 36.9C 4 38.8C So about 2.2 degC per loaded core and better overall performance. Edited February 28, 2015 by starfireprime Quote Link to comment Share on other sites More sharing options...
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