Gigabyte's New Odin GT 800W Power Supply
by Christoph Katzer on July 24, 2007 12:01 AM EST- Posted in
- Cases/Cooling/PSUs
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.
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.
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strikeback03 - Tuesday, July 24, 2007 - link
Does the software need to be running for the voltage regulation to work? Or can you make changes then close the software and have the changes still work on the PSU?Also I'd guess if UV lighting is that useful for a case you could swap the blue LEDs for some UV ones - looks like enough wire is exposed to cut the blue ones and solder in UV ones.
Oberst - Tuesday, July 24, 2007 - link
Hello,nice review (i wouldn't expect anything else of you). But I've got a question about the measuring-software: Was it reliable, when measuring voltages? You already mentioned, that the wattage was not reliable. So I'd like to know, if that was because of wrong measured amps or volts.
greets Oberst.
Christoph Katzer - Tuesday, July 24, 2007 - link
Voltages have been quite accurate; amps have been wrong in almost every case.qpwoei - Tuesday, July 24, 2007 - link
Once you've got the ripple measurements sorted out, it'd be nice to get some scope traces as the load changes. Poor transient response of the rails can cause all sorts of hard-to-diagnose problems in the real world.Christoph Katzer - Tuesday, July 24, 2007 - link
We use a scope to follow response on the rails but until now we feel the data is not good enough to present. If there would be something to extraordinary to tell we surely would.bob4432 - Tuesday, July 24, 2007 - link
what about that? a good quality unit, the Corsair 520HX seems to be a lot of people's favorite lately, how does it really stack up? or some of the FSP "Green" units - are they really that efficient? what about seasonic - really as good as everyone says?these reports are all fine and dandy, but you are catering to possibly 5% of your user base, yes even here 800W is extreme overkill.
and it is not a $$$ issue but rather a reality issue. i am surprised you guys testing these are continuing the thought process by only reviewing the upper wattage units and thus making everyone think they need one when they don't - people on review 750W psus, so i must need one...come on guys
Christoph Katzer - Tuesday, July 24, 2007 - link
Will come. No worries about that. At the moment we are just starting as you can see and of course every company wants to have the best PSU tested first. We'll have lower ones very soon but need to work on that mountain of PSUs here first. With 380w you will see a Seasonic pretty soon for example.bob4432 - Tuesday, July 24, 2007 - link
will definitely be looking forward to them :)ATWindsor - Tuesday, July 24, 2007 - link
I disagree that an OCP per rail i s a good thing, it onyl makes using the PSU more of a hassle, since you can draw a lot less from the PSU on 12V than the specs would make possible, if you are unlucky and draw most of it from one rail. Several manufacturers have one big rail without any know safety-problems, having an OCP for the combined drav from the 12V-lines however is a good thing.AtW
dare2savefreedom - Tuesday, July 24, 2007 - link
I would be interested in knowing how a psu runs with dual 8800gtxs in virginia in summertime in an old house with a window air conditioner.Not these theoretical white glove clean room lab environment tests.
triple sli 8800gtx?
come one stop playing with your iphone.