[...] where as many as 20X this number of CPUs are already in use for other altcoins. [...]
Could you kindly share where do you get this figure from?
People, are constantly doing calculations for 51% attacks, they are posted all over the place.
Just google it, if you are that interested in it, rather than being lazy and asking someone else to do your own work.
And, at least 2 of the tiny coins (minimal-like cash startups) imitating the Ethereum Foundation's algorithm open source information, have had successful 51% attacks on them - so, yes it does happen when the hashrate is really tiny on the Dagger algorithm.
However, I'd reckon that direct clone coin of Ethereum, does not have to worry about a Classic 51% attack
Where did I say anything about me being interested in 51% attack on ETH? Riddikulo asserted a claim that as many as 20X the number high end GPUs in CPU power is being used to mine other altcoins. I find that a pretty interesting claim.
My searches on that topic come up pretty empty, therefore I asked him to share the research, paper, blog post, or at least an educated guess where he gets that number from.
Perhaps you could try reading with some comprehension before calling me lazy, or at least change your nick to "thevictimofukeducationsystem".
Yeah, it is a world class education system in the UK
You must not mine at all. Nicehash multi-algo mining software can benchmark a few algorithims on CPUs.
20X is an average, because the hashrate or the values of coins is lower or it is has a low-startup investment and they tend to focus on periods of CPU mining.
The CryptoNight alogorithm is still pretty close between GPUs and CPUs.
AMD FX6300 does around 230hashes.
R9 290 does around 760hashes.
And, yes, I read it on this Forum's ANN, as well as from other websites.
As I said, you are a tad lazy!