Folding Forum

Hello,

Having read FAQ and Guides I still have questions:

1. There was information that some CPU have issues with SSE code. How can I know that my CPU does not
have such problems? If my FAH client does not write any error messages to the log file, is it enough to say,
that my CPU correctly works with FAM SIMD commands and I can enable optimized assembly code?

2. If a CPU or GPU works incorrectly due to some reasons (if it is too overclocked for example), then it
can produce wrong results. How does FAH verify, that results received from a client are correct? Can one
client, that sent wrong results, influence on the final result of an experiment? (I'm not speaking about
cheating here.)

1) If you see a message about working with standard loops and you're suddenly working very slowly, then you know SSE is not working. Generally a correct re-boot solves the problem. This normally happens only with a sudden crash like a power failure.
2) You'll see a EUE (early unit end) message and the client will download a new WU. You'll get a fraction of the points for the work done and somebody else will then try the WU that EUE'd.

The simulations are written such that incorrect results trigger error events. (EUEs) Fah has several methods for checking the accuracy of results, though not all are disclosed for security reasons.

John_Weatherman wrote:1) If you see a message about working with standard loops and you're suddenly working very slowly, then you know SSE is not working. Generally a correct re-boot solves the problem. This normally happens only with a sudden crash like a power failure.

I compared SSE enabled and disabled FAH clients and the difference is visible on my systems. I haven's seen any crashes of my FAH clients, so I expect that hardware work properly.

7im wrote:The simulations are written such that incorrect results trigger error events. (EUEs) Fah has several methods for checking the accuracy of results, though not all are disclosed for security reasons.

This is excellent if FAH has self-control, I saw one checksum problem (home directory is a network share and was lost due to a power failure), but never saw any EUE.

Thanks all for replies.