Not enough hash rate with my USB block erupters. Power problem or Pool problem?

[divyanthj]

I have about 8 ASIC USB Block erupters which I ordered from BTC guild over time. I have a plugable USB powered 10-port Hub to which I've hooked up these 8 ASICs. I'm mining bitcoins from Slush's pool, but it shows that I only have a hash rate of 1370 MH/s instead of the expected 2640 MH/s.

The power ratings on my hub's adapter are as follows.

Code:

Input 200-240 V, 50/60 Hz 0.5 A
Output 5V, 2.5 A

I'm not sure if this will help, but these are the parameters I use with BFG Miner.

Code:

 -G -S all --icarus-options 115200:1:1 --icarus-timing 3.0=100

All devices' LEDs are blinking as they should and all 8 devices are recognized by BFGminer. All 8 devices show the hashrate they should, on BFG miner.

So, does the problem lie with my devices or the pool? Am I mining the right amount of bitcoins?

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[1714062055]

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[OtaconEmmerich]

2.5A is only enough to power 5 BE's, If you want to run the rest your going to need another HUB.

[Zanatos666]

What version of bfgminer are you using?

[Trongersoll]

How long did you wait before you decided the hash rate was too low on the pool? it takes about and hour to catch up.

[kabopar]

Instead of getting another hub, you could simply get a power supply with the same plug (and polarity) but with a higher current capacity.  I got some cheap 10 port USB2.0 hubs, replaced the original (2A) power supply with a 4A units (this should be capable of supporting 8 BE's per hub, but currently only have 6 on a hub). Note that if you run a USB powered fan(s), that uses power too that needs to be accommodated by the hub's power capacity. The hubs USB data connection are daisy-chained (one hub feeds into another, which then connects to a single port on the PC), this works fine with BFGMiner.  The latest BFGMiner version (3.2.0) has a significantly lower HW error rate than earlier versions.

Cheers