I'm saying that, if a card was pushing 7Ghash/s by itself, it would probably need 30-100% cpu to keep the work coming in with no delay, or, it's a bug either in the engine or drivers.
No it wouldn't. Internally the GPU checks nonce values and only needs a new header from the CPU once every 4 billion (2^32) nonces checked.
The high CPU usage in some hardware, driver combinations is simply a bug. Nothing more. AMD drivers and SDK are horribly bugged. At one point they had a 100% CPU bug on all hardware running on windows at all times with no possible workarounds and they released a half dozen version of SDK before fixing it. Another time after fixing the 100% bug they ended up bringing it back in a newer version. There are certain versions once installed break compatiblity with older versions and make it very difficult to downgrade.
Simple verson: AMD drivers suck. There are lots and lots of bugs.
But, I didn't see anything in the change log (or im blind) stating that anything above 9 intensity would consume 100% of my cores as a future proof for ASICs. So, I'm guessing it's a bug. The weird thing is, if i switch to an older cgminer (2.6.1 for instance) the problem does not occur at intensity's higher than 9.
So, I'm not sure what to make of it.
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