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If he had XXXX he would not be getting 740 numbers.

It's a silicon lottery. As long as they are cooled you can pump them, up until they pop.

CSZiggy wrote:If he had XXXX he would not be getting 740 numbers.

It's a silicon lottery. As long as they are cooled you can pump them, up until they pop.

freq: 475 @ 620mh/s im currently with ambient at 20c, producing PCB 51; Chip 63 degrees Celcius, 12h 0-50 HW on 2/4 boards.
ambient start clsing into the 30c i will have to downclock, or risk getting up over 75 degree c thats where i have my personal threshold and i dont want to push the chip past that. Been my threshold for my KNC Titan for many years, even if it regularly ran in the high 80's aswell last summer for weeks before realising. Still purring away.

mycide wrote:
ambient start clsing into the 30c i will have to downclock, or risk getting up over 75 degree c thats where i have my personal threshold and i dont want to push the chip past that.

Agree - mine start popping even at 58C - I believe 1 chip has an issue and needs to be replaced but I have not looked into how to do that. The board accounts for more than 50% of the HW errors. looking at the profile, the two inside boards seems to have more errors.

Might need to experiment with keeping the ambient temperature down this summer.

alim wrote:

mycide wrote:
ambient start clsing into the 30c i will have to downclock, or risk getting up over 75 degree c thats where i have my personal threshold and i dont want to push the chip past that.

Agree - mine start popping even at 58C - I believe 1 chip has an issue and needs to be replaced but I have not looked into how to do that. The board accounts for more than 50% of the HW errors. looking at the profile, the two inside boards seems to have more errors.

Might need to experiment with keeping the ambient temperature down this summer.

As soon as the last batch i recieved loses warranty, i will start rearranging my boards, and overclock them aswell, most of my rigs runs with 2 boards HW free even at freq @450
i am sure i can get several rigs with better boards and push em all at 475freq or higher, 620-650mh/s with single digit or 0 HW errors/24h

This summer i will also double up my ventilation, one fiter and fan for inlet, and another fan for outlet, last summer i barely managed to keep below 30 degree ambient. and doubled up this year, heat is going to be a problem, i might even have to insulate the roof of my garage to keep sun heat out.

I'm running safely at 500, with just 1 popping. I've tried higher frequencies - at 550 the inside boards pop about 1/2.

What I really like to do is to replace the individual chip, or remove it, or have it ignored altogether.

The issue seems to be that the inside boards have hot spots. Ideas off the top of my head

1. Run with 3 rather than 4 boards at as high a frequency as possible.
2. Set up a carcass with all the troublesome boards together and run at the most optimal frequency.


Heat Reduction
1. Put the rigs on the north side in the shade (assuming you are north of the equator)
2. Use tubing on the output to take the heat into another room (either drying boots/cloths - may never need to run a dryer again OR set it up to warm an external hydroponic system).

That's all I've got for now.

alim wrote:I'm running safely at 500, with just 1 popping. I've tried higher frequencies - at 550 the inside boards pop about 1/2.

What I really like to do is to replace the individual chip, or remove it, or have it ignored altogether.

The issue seems to be that the inside boards have hot spots. Ideas off the top of my head

1. Run with 3 rather than 4 boards at as high a frequency as possible.
2. Set up a carcass with all the troublesome boards together and run at the most optimal frequency.


Heat Reduction
1. Put the rigs on the north side in the shade (assuming you are north of the equator)
2. Use tubing on the output to take the heat into another room (either drying boots/cloths - may never need to run a dryer again OR set it up to warm an external hydroponic system).

That's all I've got for now.

dont run them sitting in the sun. u seem to get problems at fairly low hashrates, bad example maybe. make sure the machine is clean, take off the fans and blow it with a compressor to make sure airflow is free. min dusts up pretty good in the garage after 6 months.

Basically my set up is air inlet - blowing air from outside to my rig are, my rigs are all positions so they suck that air in, and blow it towards the other side of the room, where i have the extraction fan in the ceiling. i then also got a second inlet for summer, and two more outlets that i need to put fans to help extract excess heat. Heat is your enemy here, dont run them to hot or u risk losing ur rigs, id clock them down or shut em off if it got to hot, so far that has not happend but 35degree C ambient is pushing it with chip nudging 75c. airflow, extract heat, provide fresh air (just not to fresh/moist/dusty.) some filter arrangement for inlet is adviced.

I am already using the excess heat being extracted out through the wall into my growhouse that is built on the side of my garage, the duct continues out of the growhouse and ends behind my air water heat pump, where it provides plenty of warm air year around making the heatpump work very efficient, over 80% save from all electric heating the house + my growhouse stays 10-15 degree celcius even during winter, tomatoes and salad/herbs basically year around. that's how you make that electric bill work for you.

@myclyde, Thanks for the great advice. They have certainly help solidify my plans on how to use the heat/output.

We don't really need to worry about getting to 35C ambient temperature here - so the idea of intake from outside is great.

Piece of useless info about Edinburgh from Google: The highest temperature ever recorded in the city was 31.4 °C (88.5 °F) on 4 August 1975 at Turnhouse Airport.

I would be really careful running at 740 MHs in the US due to the apw3 power supplies max output is 1000w @120vac where in the UK 1200w @240vac and apw3++ 1200w @120vac and 1600w @240vac. Running at that oc must be close to max psu power.

I have 4 L3+ and have them oc at max I could get without getting silly hw errors, I will eventually swap some of the boards around and get 2 with 0 hw errors and oc it as much as possible.

I have them in my garage atm with them venting outside but will be adding some ducting ac and a box to keep them as cool as possible during the UK summer