CORSAIR CMPSU-650TX vs CORSAIR CMPSU-750TX

[VinnyChase]

I will be building a gaming PC soon. The TX650 should be more than enough power if using a single video card. I don't know if I will ever use a CrossFire configuration, which begs the question. If I use the TX750 and never CrossFire will the electric bill be higher?

I'm a little confused on how power supplies work exactly. Hypothetically, if using a 1000W PSU and a 500W PSU under a 300W load would the energy cost (electric bill) be the same or would the 1000W PSU be more expensive to run?

My concern is that the TX750 would be way overkill for my system running one video card.

AMD Phenom II X3 720
GIGABYTE GA-MA790XT-UD4P
XFX HD-487A-ZHFC Radeon HD 4870 1GB
G.SKILL 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666)
Western Digital Caviar Black 640GB

 

[JohnnyLucky]

A 1000 watt power supply will only draw the amount of electricity from a wall outlet that is needed to run the system. If your system only needed 300 watts the power supply would not draw 1000 watts.

The actual issue might be power supply efficiency. However, some of the newer high quality psu's are able to operate efficiently over a much larger operating range.

 

[VinnyChase]

Yeah, I knew that a PSU only draws how much that a system uses, but I wasn't sure if there were any other intangibles. I think the main thing would be efficiency and noise level. I already received the TX750 and was debating returning it since I don't see using more than one video card for a long time, if at all. I do intend to overclock the CPU 10-20% and I think the video card I'm getting is slightly OC'd.

Thanks

 

[jsc]

If you already have the the 750, I'd suggest you keep it. I doubt if there will be much difference in the efficiency, but the 750 should be a little quieter. It will not be working as hard, so it will stay cooler, and the fan will rotate more slowly.

 

[XMSYellowbeard]

Yeah, simple shipping costs or the time to drive back to the retailer etc will offset any differences you might see between the 2 PSUs. The 750 is a good fit for that system anyway.

 

[radnor]

I have a TX750 , now with a 4850 CF and a X4 955 OCed. When i bought it i had a 4850 and Athlon 4800+ X2. Bouth my rigs are extremley stable, and i can thank to the PSU for that.

The TX750 has a monster 60a 12V rails, so it is quite future proof. It would do nicely if you ever want to got 4870 crossfire i guess.

 

[jsc]

I have TX750. It's just loafing along running a single GTX260 in an Antec 900 case. Exhaust air from the PSU is about 3 C over ambient, measured with an electronic thermometer. The PSU is virtually silent.

 

[VinnyChase]

I'm tempted to return it since I've decided that I won't CrossFire and I can save $20 at newegg or $40 at Amazon, even after return shipping. If I ever upgrade the video card a single card would most likely be more powerful than if I got another of the existing card.