X6500 Custom FPGA Miner

[MykelSilver]

Hi,

Yesterday my Northbridge 2 heatsinks (http://www.frozencpu.com/images/products/main/vid-164.jpg) arrived finally.

After mounting them on the X6500 board (with the included thermal tape), the effect of cooling disappoints a quite a bit.
The ambient temperature of my room is 17 degrees Celsius. Yet the temperature of the core is 44 degrees at 126 MH/s.
Is this normal? Is it necessary to buy additional cooling, or should I mount it with thermal glue instead of the included thermal tape?

EDIT:
The metal case of the heatsinks feels cold. Is this normal? You would think that the conduction is not alright...? I assume the temperature of the metal case should be 44 degrees ?

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[Zeronic]

I'm using Arctic Cooling MX4 thermal grease compound, with the same northbridge cooler. Ambient temp of 25C and without the 120mm avg temp at 200Mhz is 35C, with the 120mm it drop down to 30-32C.

[MykelSilver]

Thanks for your reply. So any clue what is wrong in my case? Thanks in advance

[SamHa1n]

Thanks for your reply. So any clue what is wrong in my case? Thanks in advance

If you have mount holes, mount the sink with high quality thermal paste. If you have an older unit without mount holes, use a high quality thermal epoxy ( but do it right, google it, practice on something else, you have pretty much one shot with epoxy).

The adhesive pads do not work well for fpga applications. I would guess 90% of issues when people are unable to achieve decent speed is directly related to how well the job was done mating the heat sink on to fpga core. This has been very true in my own experience, regardless of brand or type.

[MykelSilver]

Thanks for this valuable information!

[nbtcminer]

@Fizzisist / Anyone:

I recently made the switch to a 5A brick style PSU for both my X6500 (both Rev 2.0 and 3.0) and noticed some interesting changes; the number of stales/dupes has dropped on both (a noticeable amount). One hypothesis I have for the increase in performance / efficiency is based on something TheSeven mentioned a while back. He mentioned that some wallwort PSU aren't nearly as efficient as they state and don't really supply the full amount of power they are rated for. I'm guessing that my 2A wallworts weren't supplying enough power to the fans (2x92mm) to keep the units cool and the 5a brick is supplying just the right amount of power to keep the units cool / operating properly.

My question to you all is this: Would swapping to an actual computer PSU (i.e 400-500W 80PLUS bronze PSU) make a difference in terms of performance / longevity of the units?


Cheers,

Nbtcminer

[Zeronic]

Depending on model of PSU the power is far better than your wallwart. Active Power Flow Control and high quality componets will make a big differnce. I saw a similar change when I changed over from Thermaltake PSU to Seasonic PSU. I'm running my single X6500 off a 1U micro server PSU with only 2.5 rejects per hour and 1.25 Invalids per hour. After I get a few more boards I'm going to switch over to a Seasonic 560 Watt 46 Amp Unit, which can run 30 X6500 no problem.

[nbtcminer]

Depending on model of PSU the power is far better than your wallwart. Active Power Flow Control and high quality componets will make a big differnce. I saw a similar change when I changed over from Thermaltake PSU to Seasonic PSU. I'm running my single X6500 off a 1U micro server PSU with only 2.5 rejects per hour and 1.25 Invalids per hour. After I get a few more boards I'm going to switch over to a Seasonic 560 Watt 46 Amp Unit, which can run 30 X6500 no problem.

Thanks for the input Zeronic; I think I'm going to look into powering all my units via a 650W Antec Earthwatts 80Plus bronze psu

[Trance104]

Do you still have these available? I'm looking at the site that you're distributing through and they are displaying that they are out of stock.

I'd be interested in just one for now.

[ElitePork]

Looks like it will not be available until nelisky figured how to get his work out from the repo...
I'm also ready to order it

[Zeronic]

The X6500 being "Out of Stock" has nothing to do with nelisky. FPGAMining is considering where or not to do another batch of X6500. I'm also in the group of waiting to order a 2nd one.

[nbtcminer]

Just wanted to add an update regarding the X6500:

Not that long ago I went from a 2a wall wort to 5a "brick" power supply and noticed that my reject and invalid got a whole lot better. However over this weekend my 5a brick died on me (damn piece of chinese junk) and I ended up soldering my own barrel connector cable to a molex connector which I proceeded to plug into my 750W 80 plus psu. Now I have to admit that I wasn't expecting much of an improvement but things have been pretty good so far (much more stable stats) and so far 0% invalids on my X6500 Rev 2.0 (the 3.0 has the Zalman flower heatsinks and have always had 0% invalids). If you can't solder together cable or simply don't have the part, I highly recommend getting pre-made cables from a fellow by the name of Cablez on this forum.


Cheers,

nbtcminer

[torusJKL]

[...]
This is still a work in progress, but here's a shot of a temp sensor I'm testing out:



That little Frankenstein experiment is a temp sensor placed on the PCB right next to the FPGA and read out by the FT232R chip. The temperature is then available directly by the mining software.

[...]

I'm looking into reproducing your X6500 rev 2 Frankenstein experiment.

What temp sensor did you use?
Can you tell me more in detail how you connected the temp sensor to the FTR232R chip?

Can I add 2 temp sensors to the same FTR232R chip? In order to have separate temperature readings for the two chips.
And if so how would I have to connect them.

Thanks!

[fizzisist]

[...]
This is still a work in progress, but here's a shot of a temp sensor I'm testing out:

...

That little Frankenstein experiment is a temp sensor placed on the PCB right next to the FPGA and read out by the FT232R chip. The temperature is then available directly by the mining software.

[...]

I'm looking into reproducing your X6500 rev 2 Frankenstein experiment.

What temp sensor did you use?
Can you tell me more in detail how you connected the temp sensor to the FTR232R chip?

Can I add 2 temp sensors to the same FTR232R chip? In order to have separate temperature readings for the two chips.
And if so how would I have to connect them.

Thanks!

Great idea! It's really quite simple, if you can handle the fine soldering work. The sensor is the LM95071. This is the same sensor used on the Rev 3 boards, and connected the same way. We make use of the CBUS pins on the FT232R to bit bang SPI to the temp sensors, with common clock and chip select, but individual SIO. The pinout from the FT232R is:

CBUS0 (23): TEMP0_SIO
CBUS1 (22): TEMP1_SIO
CBUS2 (13): TEMP_CS
CBUS3 (14): TEMP_SCLK

Connect those to the necessary pins on the sensor and it will work perfectly in MPBM without any software tweaks needed.

Power for the sensor can be grabbed from the 2.5V VCCIO for the FT232R. An easy place to solder wires to for this is the small capacitor C2.

I glued the sensor upside down to the PCB using thermal epoxy, but there might be a nicer way to attach this to the board.

Good luck!

EDIT: There is one software related tweak needed, now that I think about it: reprogramming the FT232R EEPROM to configure those pins for GPIO. This can be done with the FT_PROG utility for Windows, or a small python script if you have the PyUSB D2XX library installed. I'll upload a script if you would like to go that route.

[fizzisist]

Good news for everyone patiently waiting to get in an X6500 order: More boards available soon!

Sorry for the long wait over the last month or so!

[fizzisist]

Cablesaurus.com has boards in stock right now!

[davecoin]

Would this work as a power source?  It seems to meet the requirements, but I just wanted to be sure prior to ordering one.

http://www.amazon.com/VDC-Switching-Power-Supply-Adapter/dp/B0066AZBP2/ref=sr_1_2?ie=UTF8&qid=1345843681&sr=8-2&keywords=2a+2.1mm+12v

Thanks,
davecoin

[fizzisist]

Would this work as a power source?  It seems to meet the requirements, but I just wanted to be sure prior to ordering one.

http://www.amazon.com/VDC-Switching-Power-Supply-Adapter/dp/B0066AZBP2/ref=sr_1_2?ie=UTF8&qid=1345843681&sr=8-2&keywords=2a+2.1mm+12v

Thanks,
davecoin

Looks good to me!

[davecoin]

Would this work as a power source?  It seems to meet the requirements, but I just wanted to be sure prior to ordering one.

http://www.amazon.com/VDC-Switching-Power-Supply-Adapter/dp/B0066AZBP2/ref=sr_1_2?ie=UTF8&qid=1345843681&sr=8-2&keywords=2a+2.1mm+12v

Thanks,
davecoin

Looks good to me!

It is working just fine so far

[max in montreal]

I just ordered one a few days ago. Mailman showed up this morning, and I have to pay 80$ in border fees...this brings up the price of the unit to 700$ delivered...sigh...