I've finally decided to build my own computer, but I need to know what parts would be the best for the list I made?
ASUS M4A78T-E (Mobo)
Athlon II X4 965 BE (CPU)
Patriot Viper II PGV34G1600ELK (RAM)
Ultra X4 750-Watt Modular Power Supply (PSU)
ATI Radeon HD 5870 Video Card (Graphics Card)
Antec 1200 (Case)
Western Digital WD15EADS 1.5Tb (HDD)
NZXT Sentry LX Dual 5.25" Fan Controller / Temperature Monitor - Black
Is it possible to have 12GB RAM on this motherboard? How would SimCity 4 and Crysis work with this? What could be changed to make it run as smooth as possible?
Everything looks fine. The PSU is o.k, but not great. I would rather you get a high quality unit from Antec or Corsair if you want to ad another 5870 down the road (I sure do ). Anyway, for the RAM it accepts up to 16GB. For now just go for an 8GB dual channel kit (4GBx2). 32-bit games can only use 2GB, but games like Crysis with a 64-bit patch can make use of more than 2GB. Even so most current 64-bit games show little benefit with more than 4GB and it will be some time before you get a benefit from having more than 8GB. It's possible to have 12GB by using an 8GB kit (4GBx2) and a 4GB kit(2GBx2). If you try to use a tri channel 12GB kit (4GBx3) your system will have to run it in single channel mode, as opposed to dual channel, which will result in a loss of performance.
I don't think having lots of memory will help much either with overclocking or getting Crysis maxed out. The area where you need to spend your money is graphics card and CPU. Seeing as you've already chosen a strong CPU, put the money saved getting a sensible amount (4GB) of RAM into the graphics card.
That harddrive is a slow green one, the green reduces performance, while saving hardly any power. Samsung Spinpoint F3, Seagate Barracuda 7200.12 and WD Caviar Blacks are the performance drives to go for.
The only site that I know of in Ireland that sells components is komplett.ie.