Avalon Overclocking Thread - Share Your Results and Tips for others

[lastbit]

Schematics are here: https://github.com/BitSyncom/avalon-ref/tree/master/PDF/SCH

The reg is a TPS40193.

Code:

The range of short circuit current thresholds that can be expected is shown in Equation 2 and Equation 3.

I SCP(max)=V ILIM(max)/RDS(on)min

I SCP(min)=V ILIM(min)/RDS(on)max

where
•
•
•
ISCP is the short circuit current
VILIM is the short circuit threshold for the low-side MOSFET
RDS(on) is the channel resistance of the low-side MOSFET
(3)
Note that due to blanking time considerations, overcurrent threshold accuracy may fall off for duty cycle greater
than 75% with the TPS40192, or 88% with the TPS40193. The reason for this is that the over current comparator
will have only a very short time to sample the SW pin voltage under these conditions and may not have time to
respond to voltages very near the threshold.
The short circuit protection threshold for the high-side MOSFET is fixed at 550 mV typical, 400 mV minimum.
This threshold is in place to provide a maximum current output using pulse by pulse current limit in the case of a
fault. The pulse will be terminated when the voltage drop acros the high side FET exceeds the short circuit
threshold. The maximum amount of current that can be specified to be sourced from a converter is found by
Equation 4.

I OUT(max)=V ILIM(min)/RDS(on)max

where
•
•
•
IOUT(max) is the maximum current that the converter is specified to source
VILIMH(min) is the short circuit threshold for the high-side MOSFET (400 mV)
RDS(on)max is the maximum resistance of the high-side MOSFET
(4)
If the required current from the converter is greater than the calculated IOUT(max) , a lower resistance high-side
MOSFET must be chosen. Both the high side and low side thresholds use temperature compensation to
approximate the change in resistance for a typical power MOSFET. This will help couneract shifts in overcurrent
thresholds as temperature increases. For this to be effective, the MOSFETs and the device must be well coupled
thermally.

The high side FET is 2x PSMN2R2-25YLC which have an IDS of 100A and  an RDS(on)max of 2.4mohm so 400mv/1.2mohm=333.33A       

Someone check my maths.      

Again I'm not a power supply expert but it looks like the limiting factor of this circuit is the inductor.
The schem says 1uh, I believe someone mentioned he had 1.5uh chokes in his unit so either ~32A or ~27A depending. I'll have to check mine the next time I have it open.

There's only one high side mos in reality in batch#3. There are 2 low side, for lowering RDS(on) and improving efficiency. Coil seems to be thermally designed for max 27A, but magnetic saturation limit is much higher. I'd guesstimate it will work with up to 40% current increase, so up to ~20% voltage and frequency increase.     

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[lastbit]

AFAIK from reading and looking at design schematics, the main regulator or w/e it is is only capable of around 20A output. We may be gettin pretty close to that on just stock overclocks...
So, overvolting safely may be out of the question.

Why you are saying is capable of only 20A?

Grr, I cant remember where yifu posted the design schematics. But the one that shows the layout for each miner board, shows in the VRM section. The main controller chip .. is it a TI or something? Look it up and its max output was like 20amps

Limit for IC is only a "soft" limit. From IC's point of view, it's more up to its ability to drive gate and Miller capacitance of output transistors.

[GenTarkin]

AFAIK from reading and looking at design schematics, the main regulator or w/e it is is only capable of around 20A output. We may be gettin pretty close to that on just stock overclocks...
So, overvolting safely may be out of the question.

Why you are saying is capable of only 20A?

Grr, I cant remember where yifu posted the design schematics. But the one that shows the layout for each miner board, shows in the VRM section. The main controller chip .. is it a TI or something? Look it up and its max output was like 20amps

Limit for IC is only a "soft" limit. From IC's point of view, it's more up to its ability to drive gate and Miller capacitance of output transistors.

http://www.ti.com/product/tps40193

The Iout, is what I was referring too, your saying thats just a soft limit?

Are the mods you speak of .. capable of working on b2 units as well? (I dont know if anything changed from b2 to b3 hash boards...)

[dogie]

AFAIK from reading and looking at design schematics, the main regulator or w/e it is is only capable of around 20A output. We may be gettin pretty close to that on just stock overclocks...
So, overvolting safely may be out of the question.

Why you are saying is capable of only 20A?

Grr, I cant remember where yifu posted the design schematics. But the one that shows the layout for each miner board, shows in the VRM section. The main controller chip .. is it a TI or something? Look it up and its max output was like 20amps

Limit for IC is only a "soft" limit. From IC's point of view, it's more up to its ability to drive gate and Miller capacitance of output transistors.

http://www.ti.com/product/tps40193

The Iout, is what I was referring too, your saying thats just a soft limit?

Are the mods you speak of .. capable of working on b2 units as well? (I dont know if anything changed from b2 to b3 hash boards...)

AFAICT from visual inspection the actual hashing boards themselves remain the same. The connector board on each module has changed, as have the PDU and control boards.

[lastbit]

http://www.ti.com/product/tps40193
The Iout, is what I was referring too, your saying thats just a soft limit?
Are the mods you speak of .. capable of working on b2 units as well? (I dont know if anything changed from b2 to b3 hash boards...)

Yes, in IC specs says it's capable of driving "up to 20A". But is not an "enforced" limit, it's up to IC ability to charge/discharge the gate charge of power mosfets.
For the low side:
 IC's reference design= 1x IRF7834: Rds=4.5mohm, Id=16A, Qg=29nC
 Avalon= 2x CSD16403Q5A, so Rds=1.1mohm, Id=56A, Qg=27nC
For the high side:
 IC's reference design: 1x IRF7466: Rds=12.5mohm, Id=11A, Qg=23nC
 Avalon(in reality): 1x Rds=4mohm, Id=100A, Qgate=39nC
IC reference design is for 10A. Based on this and mosfets' figures, I'd say IC+mosfets in Avalon are able to drive 40A.
Of course there are other limiting factors: PCB traces, Inductor, Filtering capacitors.
Inductor seems to be a Vishay Dale IHLP-5050FD 1.5uH, but I'm not 100% sure. If it is, it's specified at up to 27A (with a "hard" limit at 45A).
One thing over another, I'd say Avalon's hash unit power supply should have no problem in handling +40% more current (~20% overvoltage and overclock versus the "stable" 350MHz. But this would mean ~+70 power which I'm sure Avalon CANNOT handle as it is, at least for batch #3.

[GenTarkin]

One thing over another, I'd say Avalon's hash unit power supply should have no problem in handling +40% more current (~20% overvoltage and overclock versus the "stable" 350MHz. But this would mean ~+70 power which I'm sure Avalon CANNOT handle as it is, at least for batch #3.

Which part of Avalon you think cant handle it, just the PSU? Can always throw nice 1kw PSU's in them =) 3module is doable for sure I would think. Or are you saying something else other than PSU cant handle this much power increase?

[lastbit]

One thing over another, I'd say Avalon's hash unit power supply should have no problem in handling +40% more current (~20% overvoltage and overclock versus the "stable" 350MHz. But this would mean ~+70 power which I'm sure Avalon CANNOT handle as it is, at least for batch #3.

Which part of Avalon you think cant handle it, just the PSU? Can always throw nice 1kw PSU's in them =) 3module is doable for sure I would think. Or are you saying something else other than PSU cant handle this much power increase?

You can easily install a higher power PS. But cooling is the main problem.

[Dalkore]

Batch#:  3
Modules:4
PowerSupply: OEM
Extra CoolingSetup:  12 ton HVAC; 75F Ambient A/C Room Temp
[Firmware Version] => 20130813
Chip Frequency(Default: Advance):  350(insane)
More Options(Default: --quiet):
HashRate:   ~112.5GH/s is average; Max is 115.2GH/s
Additional Info(whatever I may have missed):
Uptime:   Ridiculously good.  Ever since my full cooling went online, I literally have not had to mess with it.  I'll update and report back after a full week.  

[GenTarkin]

Batch#:  2
Modules:3
PowerSupply: Enermax GX850 gold (OEM)
Extra CoolingSetup: replaced the 2 higher RPM Fans w/ delta 5k RPM fans, reworked wiring to modules to allow better airflow
[Firmware Version] => 20130814
Chip Frequency: 358mhz
More Options(Default: --quiet):  --failover-only --quiet --avalon-temp 49 --avalon-freq 358 --avalon-cutoff 55 --avalon-fan 90-100
HashRate:   ~84GH/s MHSav
Additional Info(whatever I may have missed): temps are 29C/40C/42C when its around 80F outside(probably 85F in the room its in), at night time when its cooler(60-70F outside) .. temps are 23/33/35 .. these Delta fans really helped the temps drop!
Power Usage @ Wall: 760-765w
Uptime:  All the time, its a tank =)... only goes down when I hit the APPLY CONFIG button =P

[greaterninja]

Batch#:  2
Modules:3
PowerSupply: Enermax GX850 gold (OEM)
Extra CoolingSetup: replaced the 2 higher RPM Fans w/ delta 5k RPM fans, reworked wiring to modules to allow better airflow
[Firmware Version] => 20130814
Chip Frequency: 358mhz
More Options(Default: --quiet):  --failover-only --quiet --avalon-temp 49 --avalon-freq 358 --avalon-cutoff 55 --avalon-fan 90-100
HashRate:   ~84GH/s MHSav
Additional Info(whatever I may have missed): temps are 29C/40C/42C when its around 80F outside(probably 85F in the room its in), at night time when its cooler(60-70F outside) .. temps are 23/33/35 .. these Delta fans really helped the temps drop!
Power Usage @ Wall: 760-765w
Uptime:  All the time, its a tank =)... only goes down when I hit the APPLY CONFIG button =P

Currently I run 354 on 4 modules stable for the last 3+ days.  Average hash is 111.4 GH/s. 


   Since 375 setting does not hash efficiently, I believe I will try Insane (350) setting and manually set 358-365 when I get home to see if hashrate increases and is more efficient.

[GenTarkin]

Batch#:  2
Modules:3
PowerSupply: Enermax GX850 gold (OEM)
Extra CoolingSetup: replaced the 2 higher RPM Fans w/ delta 5k RPM fans, reworked wiring to modules to allow better airflow
[Firmware Version] => 20130814
Chip Frequency: 358mhz
More Options(Default: --quiet):  --failover-only --quiet --avalon-temp 49 --avalon-freq 358 --avalon-cutoff 55 --avalon-fan 90-100
HashRate:   ~84GH/s MHSav
Additional Info(whatever I may have missed): temps are 29C/40C/42C when its around 80F outside(probably 85F in the room its in), at night time when its cooler(60-70F outside) .. temps are 23/33/35 .. these Delta fans really helped the temps drop!
Power Usage @ Wall: 760-765w
Uptime:  All the time, its a tank =)... only goes down when I hit the APPLY CONFIG button =P

Currently I run 354 on 4 modules stable for the last 3+ days.  Average hash is 111.4 GH/s.  


   Since 375 setting does not hash efficiently, I believe I will try Insane (350) setting and manually set 358-365 when I get home to see if hashrate increases and is more efficient.

Yeah betweeen 2-3% HW is good effeciency past that its barely any return. Just wasted energy.

[silverston]

Batch#:2
Modules:3
PowerSupply: Corsair AX1200 Gold
Extra CoolingSetup:  Replacing the thermal spacers on modules for thermal grease Arctic Ceramic
[Firmware Version] => many have tried - @ now 20130723
Chip Frequency(Default: Advance):  350(insane)
More Options(Default: --quiet): --avalon-auto, --avalon-temp 48, --avalon-cutoff 60
HashRate:   ~84Gh average
Uptime:   Max uptime  was 3 days
Power usage @ wall : 725W

[S M I L Y]

Preview of what im working on.

Im going for 1.34v, watercooling, and a 16awg wire to distribute current to the bottom of the board.


39.2k R10 piggyback resistor


watercooling channels.  Extruded alu is not fun to weld.


16awg wire. 

[greaterninja]

Preview of what im working on.

Im going for 1.34v, watercooling, and a 16awg wire to distribute current to the bottom of the board.


39.2k R10 piggyback resistor

It seems promising.  It seems like you know what you are doing.  For you and your Avalon I hope you know what you are doing haha.

[GenTarkin]

whoa that wire mod looks sick...
do you think w/o an overvolt that more consistent voltage will help HW% errors drop and thus a bit higher clock even at stock voltage? cuz that mod seems simple enough.

[Ytterbium]

whoa that wire mod looks sick...
do you think w/o an overvolt that more consistent voltage will help HW% errors drop and thus a bit higher clock even at stock voltage? cuz that mod seems simple enough.

Yup.  JFET transistors act like tiny capacitors when they're closed - the current doesn't actually stop flowing until the capacitor is 'charged'.  And of course more volts means faster charge time.

On the other hand, of course, it means more heat, and more risk of damaging your chips...

[knite]

I recently received a B2 3-module unit.

- What's the best I can do with the stock PSU, 325?
- What settings should I use? I'm currently on: --avalon-options 115200:24:10:d:355 --avalon-auto --avalon-freq 256-375 --avalon-temp 55
- If I'm upgrading my PSU, which model is most recommended?

[ProfMac]

I recently received a B2 3-module unit.

- What's the best I can do with the stock PSU, 325?
- What settings should I use? I'm currently on: --avalon-options 115200:24:10:d:355 --avalon-auto --avalon-freq 256-375 --avalon-temp 55
- If I'm upgrading my PSU, which model is most recommended?

There are many units hashing at 80-85 GH/s.

[GenTarkin]

whoa that wire mod looks sick...
do you think w/o an overvolt that more consistent voltage will help HW% errors drop and thus a bit higher clock even at stock voltage? cuz that mod seems simple enough.

Yup.  JFET transistors act like tiny capacitors when they're closed - the current doesn't actually stop flowing until the capacitor is 'charged'.  And of course more volts means faster charge time.

On the other hand, of course, it means more heat, and more risk of damaging your chips...

Can you post voltage readings on each chip since doing the wire mod? I wanna know how much its improved as far as being consistent voltage.
Any chance you can attempt OC just at stock volts using just the wire mod?

My avy, so far, using newest 0820 firmware is capable of 363-364mhz @ 1.7% HW, around temps of under 40C ... at night my avy max temp goes down to less than 35C ...
B2 - 3 module

[S M I L Y]

whoa that wire mod looks sick...
do you think w/o an overvolt that more consistent voltage will help HW% errors drop and thus a bit higher clock even at stock voltage? cuz that mod seems simple enough.

From what I have read from others on Burnins board thread they are seeing big changes in performance with just a 10mv difference.  

a 16awg wire should be good for 10a without much voltage drop.  

it will be a couple of days before I can finish up on the watercooling stuff before I can fire the boards up and take some measurements.