Graphics Card help!

Hello! thank you for checking out my thread

I want a nice graphics/video card for my Asus PC

Here are my specs: AMD Phenom II X4 830 Processor, 6GB RAM
ATI Radeon 3000 Graphics

My pc has a PCI Express 2.0 x16

I found this online... what do you think?
Should I buy this video card?
Newegg.com - ASUS EAH3870X2/G/3DHTI/1G Radeon HD 3870 X2 1GB 512-bit GDDR3 PCI Express 2.0 x16 HDCP Ready CrossFireX Support Video Card

Newegg.com - MSI R5770 Hawk Radeon HD 5770 1GB 128-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card
But you need the 6pin power cables, it should come in case if you don't have them, you'll need to connect them to molex one though.