A final update from yesterday on the USB Erupter performance.
17 hour run statistics on ozcoin using direct Stratum and
--icarus-options 115200:1:1 --icarus-timing 3.0=80
(see further below for more optimal settings)
[SUMMARY] =>
(
[0] => SUMMARY
[Elapsed] => 61325
[MHS av] => 334.00
[Found Blocks] => 0
[Getworks] => 2779
[Accepted] => 4686
[Rejected] => 5
[Hardware Errors] => 44
[Utility] => 4.58
[Discarded] => 5433
[Stale] => 4
[Get Failures] => 2
[Local Work] => 15895
[Remote Failures] => 0
[Network Blocks] => 115
[Total MH] => 20482802.5584
[Work Utility] => 4.64
[Difficulty Accepted] => 4686.00000000
[Difficulty Rejected] => 5.00000000
[Difficulty Stale] => 4.00000000
[Best Share] => 11913
)
So - less than 1% HW errors.
I'm not sure if the earlier higher figure yesterday was burn in or overnight being cooler - I'll see today - but certainly don't expect it to get over 1.5% (Ambient temperature for the last 24hours has been around 21C or less)
Accepted hash rate: Difficulty Accepted / Elapsed = 328MH/s
Work utility (4.64) = 332MH/s
So all in all performing ~10% above the expected 300MH/s
Based on those figures I'd suggest the cgminer options to get it to report a little closer to accurate MH/s:
--icarus-options 115200:1:1 --icarus-timing 3.012=100
The actual timing for mine would be 3.012=128 but I'm not sure what sort of variance there will be with the final product.
The 3.012 number helps get the MH/s display correct but doesn't affect the device performance.
The =100 number determines how long it should hash (100 = 10.0seconds) before restarting work, so if it is too long, it will allow it to go idle and thus reduce performance.
However, being a bit low (in this case 100 is 22% below the expected figure of 128 for me) has a very minor ignorable effect but allows for a large 22% performance variance with devices.
Soon I'll be updating the cgminer Icarus driver to use USB direct (it's the last untouched cgminer serial-USB driver) so these will be HotPlug also soon.
Screen cap at the same time as the above numbers:
![](https://ip.bitcointalk.org/?u=http%3A%2F%2F198.245.60.111%2FPix%2FErupter4.png&t=665&c=bFa8sZ1p7W_44g)
Edit: much later edit with a few updates:
Size: 24.5mm wide
Board alone is 45mm long
Board+USB plug is 59.5mm (of course the plug isn't removable)
Weight: 6g
Height; 6mm (the highest component)
Errors: between 1% and 1.5%
Hash rate: 336MH/s