CUDA miner is only for Litecoin, not for BTC (I think). But many thanks for your kind answer. I now understand why cgminer doesn't use the Nvidea GPU.

If your hub is not powered, you might be straining it.  You should only need 1A or so though since the Lancelot has its own power chord.

This is wrong. You can build cgminer for nvidia. The precompiled binaries are for ATI, but if you download the nvidia opencl SDK you should be able to build against it. I have done this on linux a long time ago, no idea about windows. You don't get any fan control or temperature monitoring.

it is worth to mention that NVDA hw is 3 times slower in SHA than AMD/ATI.

no

I want to use my 7970 machines for mining on ltc since they are useless now on btc for that i have a small usb devices running fine on cgminer

So i wanted to run another instance of cgminer pure solo mining with litecoin
But whatever i do it simply does not start
the weirdest of all is when i take the old reaper it runs ok and found a block

my conf in use :
{
"pools" : [
{
"name: : "Local",
"url" : "192.168.178.12:9337",
"user" : "[USER].[WORKER]",
"pass" : "[PASS]"
},
{
"name: : "Coinotron",
"url" : "coinotron.com:3334",
"user" : "[USER].[WORKER]",
"pass" : "[PASS]"
},
{
"url" : "newlc.ozco.in:9332",
"user" : "[USER].[WORKER]",
"pass" : "[PASS]"
}
],

"intensity" : "18",
"vectors" : "1",
"worksize" : "256",
"lookup-gap" : "2",
"thread-concurrency" : "21712",
"shaders" : "2048",

"gpu-engine" : "800-1000",
"gpu-fan" : "40-100",
"gpu-memclock" : "1200",
"gpu-powertune" : "10",
"gpu-vddc" : "1.100",
"temp-cutoff" : "95",
"temp-overheat" : "90",
"temp-target" : "75",

"api-port" : "4028",
"expiry" : "120",
"failover-only" : true,
"gpu-threads" : "1",

"log" : "5",
"queue" : "1",
"scan-time" : "60",
"temp-hysteresis" : "3",

"scrypt" : true,
"kernel" : "scrypt",
"kernel-path" : "/usr/local/bin"
}

the error i get after start cgminer :
[2013-07-16 23:36:02] Probing for an alive pool
[2013-07-16 23:36:02] Network difficulty changed to 0 (769.9kh/s)
[2013-07-16 23:36:02] No suitable long-poll found for http://192.168.178.12:9337

then it crashes or when i use the command for run it from command line it instant crash

There's a 3.3.2?  I'm still using 3.3.1, which is working great for me with USB Erupters.  Of course I only have 15 of them with USB 2.0 Hubs.

They're still working on the USB 3.0 Hub support.  Which was the reason I bought USB 2.0 Hubs.

Glad your working at least.
Sam

Oh, right. I forgot to mention that I excluded the hub as the problem before going to 3.1.1 by reproducing the findings with the USB Eruptors plugged in directly to the computer. I observed the same behavior where individually they work fine but if two were installed each device would mine for a bit and then enter into some sort of standby mode with solid leds (they don't both enter that state at the same time--one will get there sooner than the other). Then after a few seconds both will start hashing again simultaneously. That pattern of hashing in spurts and stalling just keeps repeating itself. I didn't time it but my guess is ~15-30sec. The computer itself is an Celeron-based Intel NUC that only has USB 2.0 ports.

I don't know if it matters but the the second miner came from BTCguild and was "branded" (I assume via the Luke-JR method) but the first comes from CanaryInTheMine and is unbranded. cgminer's udev rules seem to work fine with both as far as I can tell.

Looking back through the logs did finally notice one thing. When running the 3.2.x or github version, this happens once per reboot when cgminer is starting up:

Jul 16 00:47:02 xxx kernel: [   10.527272] cp210x ttyUSB0: cp210x converter now disconnected from ttyUSB0
Jul 16 00:47:02 xxx kernel: [   10.527304] cp210x 2-1.1.2:1.0: device disconnected
Jul 16 00:47:02 xxx kernel: [   10.588515] cp210x ttyUSB1: cp210x converter now disconnected from ttyUSB1
Jul 16 00:47:02 xxx kernel: [   10.588549] cp210x 2-1.1.4:1.0: device disconnected

When this happensdev/ttyUSB0 anddev/ttyUSB1 disappear and never return. But cgminer 3.2.x is still able to hash in spurts. I had to reboot to get 3.1.1 to work.

Yes, I concluded it was the desired behavior. Just being complete in reporting everything this time. I mostly wanted to clarify that the problem does indeed exist without USB 3.0 anywhere in the picture and it only seems to show up when more than one eruptor is installed. When the other user mentioned a problem when using an eruptor+fpga, it made me think that perhaps there's just some problem using eruptors with multiple devices on 3.2.x.

I know you have a large eruptor setup. Are you running 3.2.x? Your recommendation to someone else to run 3.1.1 a while ago is why I ended up trying that. (I saw you mention your eruptor farm in a p2pool thread and went through your post history to see if I was missing a step--initially I suspected a p2pool problem, but the 3.1.1 recommendation was on the money)