I`ve never watercooled a system, and rarely build systems that require loads of extra fans. However, it makes sense to connect a fan or pump directly to a PSU connector, rather than a motherboard header, unless fan speed control is required. Even so, it's common sense to check the current capacity of a header before attaching anthing to it. I must admit, if I attach a case fan to a header I don't bother checking. A watercooling pump (or even a large fan) is likely to draw more current than a normal fan, so connecting to a motherboard header would be unwise.
To be honest, you can connect the pump to the motherboard in the vast majority of cases but it does make it susceptable to a few things like speed changing. Pumps have a minimum power like fans, which they can operate, however most pumps require significantly more than fans. I wouldnt want cool and quiet mode to be switching off my pump when my PC idles. It doesnt really happen outside overclocking applications and such, where their temp readings are different or when the temp sensors are faulty. Either way, id still rather connect direct to PSU or to a suitable fan controller. My pumps are rated 18w each and can easily eat some of the rated at 5/10w channel controllers which are available.
Was surprised at Silicons ignorance myself but am not saying that it wont work from the motherboard, just that there are better ways to connect a pump (off topic though).
I think gritt thought that everyone replying was OCuk staff due to the fixed avatars and thought it was just OCuk vs Silicon rather than a number of
non OCuk representatives trying to help and advise him. So he probably discounted both the goodwill of the people who replied to him, as wellas the goodwill of OCuk in replacing his parts and diagnosing the problem (though they were not required to). He probably discounted them as OCuk defending OCuk reputation.
Some people are not willing to receive advice and help, these are often the ones which struggle to get anything done about the situation, as they are just left on their own asking why and blaming who. If OP was willing to remove the GPU, he would have found the problem straight away and would have known that Silicons diagnosis was unrelated to it. He would have also been able to use the PC during all his downtime, on his onboard GPU.
*edit* Since i mentioned avatars i might aswell make my christmas present request from OCuk
. Any chance that we can get alternative humerus British gangster equivalents like from Guy Ritchie films and stuff?