I totally disagree with YOU. A 400 watt is not enough for any quad and decent video card. I burned out a 600 watt OCZ high end PSU with 2 video cards (9800 GTX+), and a 550. The only ones to survive are 700 watt and above for 2 video cards. For one card 600 is nice, but 400 is not enough. Also 2 gig of ram today is not enough for many games
I think you'll find in the grand scheme of things, OCZ really doesn't make any "high end PSUs" in comparison to other brands. That's why they keep the PCP&C brand alive.
A good quality 600 watt PSU should be able to handle something like 2x4870 in crossfire.
To run a 5770, a 400 watt would be more than enough, just stick to Seasonic or other over achieving brands.
My media center PC is a Phenom II 720 with a bit of an OC, 2gb DDR2-800 and an HD4770, running on a Corsair 400w. The HD5770 uses something like 20 watts more than the 4770 on full load, so it shouldn't be a problem.
My last PC was a Phenom II 940 overclocked to 3.8GHZ, 4GB DDR2-1066, HD4890 + HD4870, a few hard drives/dvd drives and a Xonar DX. I was using a PCP&C Silencer 610w, worked like a charm for about a year.
I recently upgraded, I now have an I7 860@4ghz, hd5870, two dvd drives, two Intel SSDs, 3 hard drives, 4GB DDR3-1600, kept the Xonar DX, and the PCP&C 610w is more than enough for that.
This PSU is almost 3 years old now, no hiccups.
Look up any reviews showing "total system power usage" and you'll find that most components require much less power than you think. There are too many crappy power supplies out on the market and people are misinformed as to which brands/products are good performers.
Here is an example for you. I posted the TOTAL SYSTEM LOAD WATTAGE as reported by a review site after each graphics card:
Core i7 Test System Specs
- Intel Core i7 965 Extreme Edition (Overclocked @ 3.70GHz)
- x3 2GB G.Skill DDR3 PC3-12800 (CAS 9-9-9-24)
- Asus P6T Deluxe (Intel X58)
- OCZ GameXStream (700 watt)
- Seagate 500GB 7200-RPM (Serial ATA300)
- Asus GeForce GTX 260 (896MB) ---------------------->334w
- Asus GeForce 9800 GT (1GB)------------------------->276w
- Asus GeForce 9600 GT (512MB)---------------------->238w
- HIS Radeon HD 5850 (1GB)--------------------------->319w
- HIS Radeon HD 5770 (1GB)--------------------------->284w
- HIS Radeon HD 5750 (1GB)--------------------------->266w
- Asus Radeon HD 4870 (512MB)----------------------->335w
- HIS Radeon HD 4850 (1GB)--------------------------->268w
- HIS Radeon HD 4770 (512MB)------------------------>254w
- Asus Radeon HD 3850 (512MB)----------------------->311w
A 9800GTX+ is about 30-odd watts more than a 4850 on load, which would put it at just a few watts less than an HD5850, which from the above review you can see is using about 320 watts at load for the entire system.
So long as the PSU can dish out the required amps, you really don't need to go overkill. Most good quality 500 watt supplies would have enough amperage to operate an HD5850 and likely a 5870 no problem.