Hi,

I need some solid advice on a few items in my spec, as i'm getting mixed opinions on several factors, so i need someone with a similar setup to comment if possible. 

**** This is for LTC mining.

Motherboard: Gigabyte 990FXA-UD3
CPU: AMD Bulldozer FX-4 Quad Core 4100 Black Edition 3.60Ghz
Memory: 8GB DDR3
GPU: 4 x Gigabyte ATi Radeon HD 7950
PSU: OCZ ZX Series 1250W '80 Plus Gold' Modular Power Supply
Case: DIY Open frame design with some extra fans.


1) I've been told the cpu is too much, and i can get away with a Sempron - the last thing i want to do is limit the system due to lack of cpu power.

2) Do i need active PCIe risers?  The board is a 5 slot pcie 16x, i'm only going to be using 4.  Can i get away with just cheap standard riser cables?

Thanks,