Definitely check local stores and places like Newegg for Black Friday specials. Each blade will pull about 80-90W and about ~7A. For 5 blades you will probably have roughly 450W and 40A draw. The trouble with this though, is even though a power supply is rated for 450W and 40A, if you have it under this load constantly you will run into heat issues and fry the thing. Leave a decent amount of overhead between the load you expect and the power supply rating. So for a constant 450W load I would recommend probably no less than a 600W power supply, and going higher wouldn't hurt. Even a 600 will probably still run pretty warm at that load.
The next issue is making sure that the 12V rails can handle the current draw that 5 blades will create. Each blade will theoretically draw around 7A, but the same issue I mentioned before still applies, if you keep the rail under the full load that it is rated for constantly, you will melt wires and capacitors for sure. I would try to find a power supply that has around 50A total rated current on the 12V rails. The ones I have laying around look to be around 30-40A total but none of them are high-end by any means. You certainly may find a mid-to-high grade power supply that meets these requirements. It may also be worth considering that you could split the blades between two power supplies if you happen to find some that are cheap in the 300-400W range and have maybe 20-30A rated 12V rails, as these would be considerably cheaper, would just be up to you to do the math.
Sorry I can't provide specific models that would be good. I didn't go shopping for power supplies when I got started with mining as I only had one blade and was able to power it off what I already had at home.
Thanks for the heads up mate. In the same store they offer Cooler Master GM750 for about 73Euro which has 62A on the 12V(single) rail according to a french website and 6x4pin connectors. Any thoughts on that one? Regards
