Like we have already said several times, our preferred architecture for power supplies starting at 1,000 W is the design using two transformers, making the power supply to have two real and completely independent +12 V rails. This provides higher current limits and also makes sure that the transformer isn’t the component limiting the maximum current the system can draw from the power supply.
Even though we still think that, we were really surprised by the architecture used on OCZ ProXStream 1000 W - synchronous -, which uses high-current power MOSFET transistors to make the rectification instead of using power Schottky rectifiers. In theory this provides a higher efficiency, but the reality was very different.
This architecture allowed OCZ ProXStream 1000 W to truly deliver 1,000 W under a room temperature of 50º C, which is outstanding – but, unfortunately, this isn’t translated into an outstanding product.
At a first sigh creating a 1,000 W power supply using the same standard ATX size seems to be a great idea, but the problem is that power supplies on this range simply don’t fit such small form factor. OCZ opted to use an intricate design using two stacked printed circuit boards and one small 80-mm fan on the rear, leading this product to face serious thermal issues: when pulling the full 1,000 W the temperature of the power supply skyrocketed to 68º C (this is so hot that you can actually burn your fingers by touching it).
Based on that we think that for 1,000 W power supplies the best solution is still use a bigger form factor with a 120- or 140-mm fan installed on the bottom of the unit.
The 80-mm fan wasn't capable of correctly dissipating the amount of heat produced by the power supply and also generated a lot of noise, as it was always spinning at its full speed during our tests.
While this power supply could achieve an efficiency on the same level of other high-efficient power supplies (83-84%) when it was loaded up to 60% of its capacity (i.e. up to 600W) when we loaded it with 800 W its efficiency dropped to 79.6% and at full load its efficiency dropped to 74.5%.
Even though it is cheaper than other 1,000 W power supplies available on the market and it can truly deliver 1,000 W at 50º C we simply can’t recommend this power supply mainly because of its working temperature, since it will overheat your system.
As a final reminder, if you buy this unit and will use it with just two video cards under SLI or CrossFire, make sure to use PCIE1 and PCIE3 connectors (and not PCIE1 and PCIE2) for a better power distribution.
