Right now OCZ has the advantage of being the only manufacturer with high-wattage 80 Plus Gold-certified power supplies on the market. If you have a lot of money and are looking for a high-end 1,000 W power supply, Z Series 1000 W may be an option. This is definitely not a product for users with tight budgets, though.
Internally we discovered that Z Series 1000 W is based on the same project as the 850 W version but with one additional active PFC transistor and upgraded rectifying bridges.
We saw efficiency between 87.8% and 89.6% when we pulled up to 800 W from it. But at 1000 W efficiency dropped to 84.3%, but this may also be caused by the different load pattern we had to use to overcome the limitation in our load tester (see our full test results for a better explanation).
At 1000 W we also saw noise level a little bit above the maximum allowed at -12 V and the +3.3 V output at only 3.06 V (while the minimum allowed is 3.135 V). Unfortunately these two flaws prevent us from recommending this unit. Carrying a heavy price tag (USD 260 – USD 290), we expected to see a flawless product, even though we know that almost no user will pull anywhere near 1000 W and thus these flaws won’t be apparent.
Updated on March 12, 2010: OCZ has just dropped the price of this power supply to USD 244 at Newegg.com (USD 214 after a mail-in rebate), which is also offering free shipping now. This improved a lot the cost/benefit ratio of this product.