Why does CG miner get less hash rate with my BFL single?

[Maidak]

I uploaded the Firmware – 864 mh/s ran a diag on it had no throttling on a light diag and it was running at a steady 864mh/s using easyminer. I went ahead loaded up cgminer and it fluxes between 700-819mh/s does anyone know why its doing this or a possible solution?

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[DrHaribo]

Maybe easyminer is not actually measuring the hash rate? Is it not deviating from 864 mh/s at all?

When I added BFL support to my miner I even made it drop hash rate on block changes according to how many hashes are wasted. The way BFL devices work you waste some hashes on every block change when you cancel the old work. That's because the device has already done some work but there is no way to get the results (if any) when you cancel. At that point the work result is stale anyway, you'd want to get the results as they are found so you can make use of them.

So what to display? The work being done? Or the work that is actually useful, the effective hash rate? I decided to go with the latter. Not sure what cgminer is doing.

[rjk]

cgminer uses some kind of averaging mechanism that isn't very smooth, so it fluctuates a bit.

[P_Shep]

cgminer shows the effective hashrate. It'll be less than the claimed hashrate as it includes the time taken to submit and retrieve results from the device, which will be a few ms. During that time the single is idle. Nothing anyone can do about that.

[-ck]

cgminer shows the effective hashrate. It'll be less than the claimed hashrate as it includes the time taken to submit and retrieve results from the device, which will be a few ms. During that time the single is idle. Nothing anyone can do about that.

cgminer gets work long before it runs out of work. That should not impact the hashrate. If there's an issue with TRUE hashrate being low, it's a bug in the BFL device implementation in cgminer. Alas I don't have an FPGA of any sort, including a BFL single, so the code is almost 100% dependent on luke-jr so ping him.

[Luke-Jr]

I uploaded the Firmware – 864 mh/s ran a diag on it had no throttling on a light diag and it was running at a steady 864mh/s using easyminer. I went ahead loaded up cgminer and it fluxes between 700-819mh/s does anyone know why its doing this or a possible solution?

Most likely your environment can't handle that speed. Try cooling it to about 70 F ambient

[Maidak]

The room temp is about 70-75F(depends how hot outside it is I only have window AC) where I mine and I also have a box fan right above this bfl single , I don't get any throttling with the regular 832 firmware which I just switched to until it cools down outside. If you have/know of any other cheap cooling suggestions please let me know. I guess my box fan thats inches away from it does minimal help.

EDIT: moved to the 832 firmware and this thing is running as hot as 54.9c but not throttling on the 864 firmware it wont go past 54c without throttling?