ATI Radeon™ HD 4870 System Requirements
PCI Express® based PC is required with one X16 lane graphics slot available on the motherboard 500 Watt or greater power supply with two 75W 6-pin PCI Express® power connectors recommended (600 Watt and four 6-pin connectors for ATI CrossFireX™ technology in dual mode)
Certified power supplies are recommended. Refer to http://ati.amd.com/certifiedPSU for a list of Certified products
Minimum 1GB of system memory
Installation software requires CD-ROM drive
DVD playback requires DVD drive
Blu-ray™ playback requires Blu-ray drive
For a complete ATI CrossFireX™ system, a second ATI Radeon™ HD 4870 graphics card, an ATI CrossFireX Ready motherboard and one ATI CrossFireX Bridge Interconnect cable per graphics card (included) are required
The recommended PSU is for the entire system.
U can go with this Antec 650W are more that the PSU that u need, but can handle ur future upgrades.
Coolermaster don't makes a very good PSUs, so, try to avoid it.
Newegg has the corsair tx650 today for $59.00 after rebate, good?
If you are thinking about doing CF, don't buy it. It hasn't enough PCIe conectors. You need four 6-pin connectors and it has only two. You will be forced to use Molex to PCIe adapters, which is NOT recommended. So even if your PSU has MORE than ample power for your CF4870, since it doesn't come with all of the appropriate connectors, go for another power supply.