btw the mobo you suggested to fara is trash because it has 3 PCI-E x16 slots but only 16 lanes overall. which means either 16/0/0 or 8/8/0 or 8/4/4. pretty pathetic for a mobo with 3 slots, dont you think, mister all knowing master PC pimper? funny.. you just said that you know how to select a motherboard because you know what PCI-E x16 means 
Never mentioned or said that im a "all knowing PC pimper" , and never said i knew how to select a motherboard. I said i know that a graphics card needs a PCI-e x16 slot to be able to operate. I know that a second graphics card would most likely run at 20 % capacity because its only there to assist when the primary card has used all its capacity and that goes for almost all PC setups. Eitherway i know enough to help Faraday out to select some options for his upgrade.
Anyway in my honest opinion you start to become more and more of an asshole these days bikedriver.... I never even tried to insult you in this topic and yet you insult me on purpose through all your replies.
Back on topic:
Sata 3 would be a good idea to upgrade to. I have a motherboard that supports Sata 2 and Sata 3. But it would be more interesting to use a SSD for the operating system (maybe a few games on it aswell) and use some SATA 3 HDD's. That stuff would probably run into the 400 euro's though alltogether so you would have about 600 left for the rest of the PC which would be enough considering you dont need a new graphics card as you said. Anyway the benefit would be the difference between speed. Sata 2 runs at 3 Gbps and the Sata 3 does 6 Gbps transfer speed. Sata 2 is also known as Sata 300 and Sata 3 as Sata600. Benefit would basically be higher speeds with transfer, read and write.
If you want you could buy a second GTX550 TI of the same brand and same make/model So that it will be almost identical to the one you have (i say almost identical because not 1 piece of hardware is the same, not even Memory modules from the same batch and series)
Just replace the 2 video cards on the list i gave you, and change the motherboard to something bikedriver would pick.
Heres the list of the new setup with the GTX550 TI
CPU: AMD FX 8150 Black Edition 3.6GHz 8MB AM3+
http://tweakers.net/pricewatch/292705/amd-fx-8150-black-edition.htmlMobo: ASRock Fatal1ty 990FX Professional
http://tweakers.net/pricewatch/286666/asrock-fatal1ty-990fx-professional.htmlGFX: Club 3D GeForce GTX 550Ti (Could be different brand like Matrox or another brand that has a GTX 550 TI GPU chipset) Just make sure its the same you got right now
Memory: Kingston ValueRAM 16 GB DDR3-1333Mhz Quad-Kit
http://tweakers.net/pricewatch/302302/kingston-kvr1333d3n9k4-16g.htmlPSU: Cooler Master - Silent Pro M1000 - 1000 Watt
http://tweakers.net/pricewatch/247888/cooler-master-silent-pro-m1000.html#tab:pricesCooling: You got to see about that stuff yourself as you want to keep your case. Add extra fans if you have open slots for it. If not you might want to invest in a new case with good airflow and cable management. To optimize the cooling capabilities because you dont want to run a PC to hot nowadays specially with the summer comming up. Last summer my PC ran up to 65 celsius on graphics card and 60 celsius on CPU. With the new cooling its running 30c cooler on load and idle even cooler.
As i understand it right now, the mobo on this list does 16 lanes 16 lanes and 4 lanes eitherway ill let bikedriver bitch at me again about that if im wrong.
If you dont want the second graphics card make sure to change the Powersupply to something like 700 - 750 Watts (could be to much still im not entirely sure how much your graphics card uses at the moment. The new CPU runs at 125 Watts i believe which is pretty standard for most CPU's of AMD
Let me know exactly what you would like and what you dont want. And ill probably be able to help you out even more.
VC-MP: 
