Hi guys im about to build a computer to replace my old computer and was wondering how much watts would i need to power up my system. i know that im gonna go with the Corsair TX series PSU, here are my spec on the system
-Intel core 2 duo extreme x6800 2.93gz (MIGHT OC)
-4gb or 8gb ddr2 1066
-Radeon HD 4870 (MIGHT run crossfire with another 4870)
-1x seagate 7200.12 1tb
-1x WD black 1tb
-1x 22x dvd burner
-1x blu ray drive
-1x samsung 22" monitor
i was looking at the Corsair 650tx or 750tx PSU will that be enough or should i get more watts?
The general rule of thumb is a high quality 500 - 550 watt power supply can easily power any single video card made and depending on the video card sometimes two video cards operating in dual mode. A high quality 750 watt power supply can easily power two video cards operating in dual mode.
Your list shows two 4870 cards operating in Crossfire mode. Two 4870 video cards operating in Crossfire mode use a combined total of about 295 watts and 25 amps at full load. The two video cards use a lot more power than the rest of your components combined. The source of the information is an article about video power consumption published last January right here at Tom's hardware.
The Corsair 550 watt power supply is an excellent power supply that can easily power your components. It has a single large 12 volt rail rated at 41 amps. You'll be in the range for peak efficiency.
But you will need PCI-e adapters if you are going to run two 4870's. A Corsair 550 has enough power. A Corsair 650 has plenty of power. But the first PSU that has four "6+2" PCI-e power cables is the TX750.