Topic: New Official AMT Thread - page 108. (Read 149472 times)

If you mean top side, just follow BMch's example and use a long one. Just be sure to find a way to bolt it down so it doesn't fall off.

I'm not too familiar with the characteristics of thermal tape, however I do know for thermal paste, a lot of them start flowing when heated up.  So if thermal tape is like this, then these chips would just fall off when given enough heat.

Yes, in my opinion very botched layouts. However - remember that the chips were first tested what, late Dec/early Jan? BMch and AMT had no idea of the power loads the chips would produce and had planned on it being a lot less. Technobit being a bit hobbiest-orientated had the time to deal with the real-world specs and before selling their systems had the advantage of seeing the trouble BMch ran into. Also helps that they started with 2 and 4 chip single boards to cut their teeth on.

Le sigh... To answer some question points posted, one more time thermal/power design 101:
Thermal flow of the A1 chip. Look at the A1 data sheet on Github.
70% goes out the bottom, through thermal vias on the board and then to the main heat sink on the backside. That leaves 30% out the top/sides. Obviously no one ran the math to know what that means for power in/sink capacity (inc airflow used)/chip temp on the top side much less what the die temp is based on the heatsinks used top & bottom along with their required airflows. I'd guess that like many non-design folks do they just thought 'big sink and a few smaller ones on top will be fine'...

Physical layout - "okay even if the chips are all bunched together".
No 'if'. That is how it should have been done to begin with.
It makes thermal control much easier to deal with - including overtemp sensing... (is there any?)

Same with clustering the Vcore buck inductors much closer to the chips not to mention more point-of-load filtering surrounding the chip cluster as Technobit uses. From the power standpoint, given the low voltages used distance between the Vcore supplies and the chips must be as minimal as possible to keep losses on the power planes/traces to an absolute minimum. The A1 spec says max core current is 20amps. It does *not* make any mention of spike loads - all processors have them and typically are over 2x the average running value. Spread out as everything is on the Bitmine-AMT boards I'd expect to see serious fluctations if anyone bothered to probe the chips power pins...

Use of thermal tape - really only advised if there are no shear loads put on the heatsink. If there are (gravity, g-forces) maximum permissible temps and load values must be within the mfrg recommendations or other means to secure are needed.

I have good news, and bad news. 6/10 of my cards are working, the other 4 don't even show up on a backplane. I never received the backplane they said they sent to me, and I am furious. Also, I made my first bitcoin in 2 weeks of mining! Yay!. Thanks to AMT for the delays and nonworking equipment, resulting in IMPOSSIBLE ROI, and frustrating customer/company relations.

~Casey

I for one, never agreed to this.

There's no evidence that this is even true.   The 5 board miners that have been shipped are capable only of 1 THs.  This is the same number of chips as the equivalent Bitmine system that is rates at 1 THs.  There is no evidence of a 1.2 THs system that can accomodate 6 boards.  In fact, there isn't even any evidence of a backplane that can accomodate 6 boards.

So what did exactly did AMT sell to its customer when said product doesn't even exist?

Sorry for disagreeing, but the 1.2TH/s does exist and AMT shipped out hundreds of them.

https://bitcointalksearch.org/topic/m.5962169


Since I just proved that one of your statements was in error, the rest of your post must be fud.

A better coincraft A1 design is to have all the A1 chips bunched together so that you can share some some kick-ass heat sink.  GPU users go to great lengths to remove the stock heatsink and replace it with something more effective.

The technobit and dragon boards both have the A1 chips clustered close together.   

All this discussion is moot now since AMT is like 2 months delayed and the competition is delivery goods that AMT can't match in price.

It's screwed in, also I have it in a military style 10 PCI case + 4 GPUs which has the heatsink going sideways. The mounting is weird, but I believe screws may be coming from the bottom of the board. This heat sink is crazy high, and would never fit in a regular case. This is one of my smaller PCs used for QA and testing

http://www.newegg.com/Product/Product.aspx?Item=N82E16835103106

Case

http://www.aerocool.us/strikex/strikex_st_black.html

anyone have an idea of an alternative heat sink that can be attached to the AMT board?

I can't tell if its screwed or not, but the sheer weight of the thing should provide enough pressure between the heatsink and the chip.  

Yes, of course it is a PC.  You think a miner requires a lesser quality heat sink?   Look at the GPUs out there,  those are also serious quality heat sinks.   Look at the design of Cointerra,  they got liquid cooled heat sinks.

So what is it about a Coincraft A1 chip that it requires a lesser quality heat sink?   You can't cheat physics here.  CPUs and GPUs all are at 28nm and have speeds that are similar to this miner.   All that electrons flowing at that speed creates the heat.    All that computation creates the heat.  

Yeah if option one is just a rehash of what I got I really don't want it.

Nobody should want the *old design*.   Nobody has shown it to work reliably.   If you want to risk burning down your home, then maybe.

Umm you do know you are looking at a motherboard with a heatsink resting on the CPU slot right? And its not even screwed in...its resting there. Its not a fully assembled board.....this is a PC not a miner....not sure if you are aware of that based on what you just said.

Well if they just have us send the hardware striaght to technobit directly it sidesteps that whole situation altogether. But yea you make a point in the little things.

How is the heat sink attached to the chip?  There are some spring loaded screws that keeps the pressure constant.  You can just put some sticky thermal tape on this.

I've had CPUs fail simply because the thermal paste was not properly applied. Now imagine this AMT system that has to run at non-nominal speeds for 24 x 7 x 365.  

Man.... we are so screwed!!!

I thought they were just shipping out surplus on the old design for option 1? For my part I would not want that old design. The technobit seems to be more stable and is working from what people are indicating on their board.