Post
Topic
Board Mining (Altcoins)
Re: GridSeed 5-chip USB miner voltage mod
by
amix
on 01/05/2014, 19:17:54 UTC
Hey everyone, Just wanted to report back on my 10 miners from gaw,
2/10 did not work out of the box,

1 had clamped the fan wires and shorted everything out when I plugged it in. - Fixed this by repairing the fan wires
1 hashed, but nothing got accepted - fixed this by reflowing the solder with a heat gun... hashing like a champ now.

I modded 4 with the 49.9K resistor, and was running them averaged 1225mhz stable / average 507 khash and found the heat and power consumption excessive - 29ish watts when pods were hot.
I now have modded all to with a 47K resistor and total mhz average after tuning is 1190mhz / 501

47K vs 49.9K Comparison:

                       Hashrate Ave.        Watts            MHz (ave after chip tuning)        hash /Watt
47K                     501.65                20-22          1190                                              22.8
49.9K                   507.6                 28-29          1225                                              17.5


My definitive Thoughts
-Use a 47K resistor - the extra heat / power management is not worth the minimal hashrate increase.
-use sandor111's cpuminer
-No HW errors does not mean your miner is running optimally, some gridseeds will run slowly at clocks that are unstable, but not throw HW errors.
-use autotune for debugging and testing max frequencies of chips, but lock them in manually in your config script.


46.2K draw 1.43A  17.16W /MHZ 1160 /hash rate 490
 5W extra for 11k with the 47K!
watt is effectored by the resistor AND MHZ, so it good to put lower resistor and higher hash rate, as opposed to higher reisitor and lower hash rate.