Gigabyte's New Odin GT 800W Power Supply

OCP Tests

In addition to transient testing, we also wanted to look at how the power supplies deal with Over Current Protection (OCP). OCP is an important safety feature that should be present on all power supplies. OCP guards the power supply and the attached components from damage that can occur when too much current is required by any of the rails. In the best case scenario, OCP should kick in and cause the power supply to simply shut down if a rail is stressed to heavily. If this doesn't happen the OPP (Over Power Protection) of our Chroma unit will kick in to save our test equipment. In a real PC, if OCP fails to work the hardware will continue to run until the cables melt, a system crash caused by out of spec voltages changes the demand on the PSU, or in the most extreme cases the power supply explodes. Needless to say, if any of the above happen there is a good chance other hardware could be damaged in the process.

Our OCP test using the Chroma equipment applies a specified amount of load to each rail of the power supply. The test always starts at no load and ends at an amount we set. The highest load always depends on the rated output from the manufacturer - enough that OCP should trigger. If OCP fails to activate, we don't need to worry since we have an OPP installed on the Chroma (and there's no PC equipment attached). We have set the step of each rising load to 2.5A, which will be added every two seconds during the test.

On the graph you will see only the 12V rails. This is because we couldn't apply any load for the OCP test to the lower rails like 3.3V and 5V. When we did so the power supply immediately shut down with no obvious reason. We had to cut the input and couldn't restart the procedure normally immediately after this occurred, so no test on these rails was possible.


As you can see we could apply a load of 24-25A on each rail. This is the usual amount of an OCP, regardless of what the label says about the rated output. There is always a little room for peak load with each power supply. Note that the load from each OCP test is applied to each rail separately. This means that if you wanted to do this test with all rails at the same time it would not be possible without greatly exceeding the rated output of the power supply. The combined power on the label states 744W, which means we could apply around 62A on all the 12V rails at the same time. Divided by four this makes around 15A per rail, which we have seen on a high static load test.