Topic: Avalon ASIC users thread - page 145. (Read 438516 times)

here's ckolivas firmware with 325 Mhz setting.  but on ozcoin i'm only registering a mere 39416 MH/s.  what gives?

ADVANCED OVERCLOCKING TECHNIQUES

After typing out the above - relatively safe - method, I thought we might explore some best practices for finding the true optimum speed of your individual Avalon.

As I understand it, the -auto option will simply increase clockspeed slowly until an arbitrary number of HW errors are produced. This is a quick and easy way of doing things and very useful, but it's not perfect...

Overclocking hardware for long periods of time is all about balance. Anyone familiar with regular CPU overclocking will know that you will normally hit a wall where increasing voltage will begin to experience diminishing return with respect to clock speed. This wall is usually parabolic and once you approach this level you will require excessive amounts of voltage and cooling to go any further. This may be acceptable when trying to reach a world record on a "suicide run" but it will not cut it for a system that you want to be running 24/7 for as long as it remains profitable.


OK, that's all fine and dandy with a regular CPU, but in the case of a regular CPU, just one error can be enough to freeze the system and force a reboot.
- these ASIC's seem different. They are much more forgiving of errors and will happily continue to try their calculations even if they get half of them wrong, lol./

-- the thing I'd like to determine, is whether or not the HW error rate is parabolic? (I would expect that it is, from prior experience)

BUT  ...
There is a chance that when dealing with so many chips, it may be possible that only a few chips are giving HW errors and that you may be able to reach much higher clock speed and effective hash rate by exceeding the arbitrary limit set in the -auto function of the firmware. Conversely it may be possible that reducing your clock speed by only a small amount could result in a drastic drop in HW errors and effectively give you a higher accepted hashrate.

The only way to know for sure is through thorough testing. Every device, every chip will respond slightly differently. This is why I love overclocking. except ram timings, don't even get me started on ram timings  

This is how I did it. (was confirmed by CK to be a sensible way to determine your individual device's optimum speed)

- make sure that you have some free time and that you can actively monitor your device for the next hour or two (not necessarily mandatory, but prudent)
- in the cgminer configuration tab, in the "more options" window, enter --avalon-auto and save and apply (personally, I usually do a hard boot after this, just to be sure)
- watch your chip frequency climb. (I'd recommend refreshing to check your speed and temps every 10 minutes or so. The software is designed to find a sweet spot where your speed is high and your HW errors are at an acceptable rate. It is not mandatory to actively check, but anything is possible and neither myself nor ckolivas are responsible if this sets your avalon on fire  )

- after a while your frequency should settle into a certain range (for me this was around 349-351)
- at this point you can remove the -auto command and just put in whatever clockspeed you deem reasonable (I recommend you set your clock a little lower than where the -auto setting started to level off. Personally, I chose 345 to give a little breathing space.)
- reboot your device to ensure that the new settings are applied and you should be good to go.

A couple notes:
- this will likely reduce the lifespan of your Avalon.
- there is always a risk involved in running a chip beyond its designed specifications.
- make sure you continue to monitor the temperatures and your accepted/HW error ratio - it is possible that a lower clockspeed may result in less HW errors and effectively get you a better score at your pool. I recommend watching the reported speed on your pool closely to see if it starts to decrease for an extended period (this number will likely fluctuate greatly, but if it continues to drop, better check your speed)

Again, I take no responsibility if this fries your Avalon, and it will most definitely void your (non-existent) warranty.

Have fun!

how do i overclock ckolivas firmware?

The yellow tape, kapton tape, is just to communicate to users that nothing should be plugged into this port (removing fuse F1 makes this port un-powered). Leave the tape.

this seemed to do it.

hashing away altho at low 60K MH/s levels.  better than nothing at this point.

will try tweaking cgminer clock rates.

there is nothing plugged into this usb port yet it is covered with yellow tape? 

any reason for this?

are you guys removing the yellow tape?

this is a batch #2 that had firmware 20130419.

is it possible this unit still has that F1 fuse?

i only received this 2 days ago so according to wiki it's already been removed.

edit:  just checked and it HAS been removed.

I'd suggest you try reflashing with "keep settings" UN-checked. This will reset your machine to defaults so you will have to set your password, network settings, turn off the WIFI, etc... just like you did when you first received your machine.

still sick:

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no, i was told to keep it checked

that's what the wiki says to do too.

@cypherdoc:

Did you check all the connections inside the box ? All flat cables pushed in the sockets ?

Maybe change the USB cable into another port of the hub ?

Diagnostics from the Network-tab are functioning ? connection ok ?

What's visable in Cgminer API log ?

Did you un-check the box that said "keep settings"?

Dead PSU?

just upgraded firmware to ckolivas latest version:  http://ck.kolivas.org/apps/cgminer/avalon/20130627/openwrt-ar71xx-generic-tl-wr703n-v1-squashfs-factory.bin

despite multiple restarts, reboots, hard reboots i still don't get hashing

any suggestions?:

Avalon vertical, external psu and vent blowing to the bottemplate.
Mid-fan (fan2) blowing max rpm, other fans auto.

My ambient basement temp = 20-23 degrees.

Right now both fans are on auto again and therefor Temp2 is over 40.

nvm.  ozcoin registering properly.

finally got it to work with ozcoin.

any idea why registered hashrate at ozcoin would be half 33 MH/s vs. 66 MH/s in cgminer status?