I was looking for something in the 750-850W range and saw some nice looking Corsair PSU's. The modular ones are quite a bit more money however, so could anyone tell me if for my build going modular would actually eliminate any cables?
The answer to your question is yes. With a modular power supply you only use necessary power cables. Unlike a hardwired power supplies you will not have a bunch of unused power cables. The modular power supplies are convenient for cable management. No need to hide a bunch of unusued cables.
BTW - If you are positive your are only going to install one ATI Radeon HD 5830 video card, then a 750 or 850 watt power supply is total overkill.
Here are the official ATI power recommendations for the Radeon HD 5830 video card:
500 Watt or greater power supply with two, 75 watt, 6-pin PCI Express® power connectors
600 Watt or greater power supply with four, 75 watt, 6-pin PCI Express® power connectors for ATI CrossFireX™ technology in dual mode
The recommendations are for an entire pc system.
Corsair and Seasonic are two brands that have a reputation for high quality power supplies that consistently earn high marks in technical reviews. They are reliable, stable, and come with a 5 year warranty. Some of the newer models come with a 7 year warranty. Lately we've been seeing a few other brands offering some high quality units.
I'm assuming that you're only planning on using a single GPU? If you want to be safe, then go for a good 600-650W unit, following JohnnyLucky's recommendations. I'd say that the current-trend is that PC power consumption will be decreasing rather than increasing in the future. There's an awful lot of emphasis on things being 'green' and efficient and this seems to be the way things are going. You should be fine for a long time with a PSU of this output.
The CP-850 ha by far the best price / performance ratio in the 850 watt category but it only fits in 5 Antec Cases. The 1200, P182, P193 and the two upcoming cases in the Dark Fleet Series. If you don't yet have a case, there are some nice newegg combos for this PSU:
For comparison purposes , the list below contains performance ratings (10 scale) at jonnyguru.com / prices as per newegg on 02/21/2010 and ones w/ double asterisks (**) made it onto silentpcreview.com's Editor's Choice List meaning they excelled at both electronic and acoustic performance:
As to the modular thing, not having extra cables is a wonderful thing but it's often over played. 100% modular does nothing for you. What's the point of having the 24 pin MoBo connector, 8 pin EPS cable modular ? Can you possible have a build that doesn't use the 24 pin. All that is accomplished by having the 24 pin cable modular is the addition of a minor amount of electrical resistance and another failure point due to it coming loose or bending pins. 100% modular is kinda like providing a Jeep with 5 spare tire mounts on the back ....I get the idea for the spare tire, but won't you be using the other 4 tires every time you drive the car ?
Most hi end PSU's today are what's called "hybrid modular" whereby the necessary cables are hardwired and the optional cables. To garner that lately important 80 plus certifications, manufacturers are paying more attention to the teeny bit of resistance that the connector adds.