This review is one of a series of PSU reviews, if you have not read any of the others you can read all about the test set up and methodology below.
  1. Testing Overview
  2. Wattage
  3. Parameters
  4. Methodology


OCZ ModStream 520W

OCZ started out as a performance memory company.  When they came out with power supplies, I was both skeptical and curious.  I scored a few units and headed back to the.. er.. well... the dining room table.

The OCZ Modstream is a modular power supply with one large, quiet, 120MM fan.

The 120MM fan features four LED's that fire inward towards the fan blades.  Neat effect.  Makes me wish this didn't have to go inside of the case.

The OCZ Modstream has a nice look to it.  One fan with blue LED's, stainless steel braided cables with UV reactive jackets and blue ends.  A very nice looking power supply.  Of course, it also had... What kind of finish boys and girls?  That's right... A TITANIUM finish.

Modular cables are like a combination of the best and worst of all three modular power supplies we've reviewed.

I was a little disappointed with the modular cables.  This, and the quantity of cables (I'll touch on that later) is what's holding this power supply back from scoring a 10.  The ends are like the A.C. Ryan or Mad Dog.  Regular connectors with heat shrink about 1/2 inch from the back of the Molex so we can see all of the wires.  The X-Connect has me spoiled, but I guess Ultra has the market cornered on plastic Molex covers.  On the power supply end of the cables, we have what made me NOT like the X-Connect modular cables:  Regular 4-pin Molexes.  Although they "shouldn't" come loose, I've already heard it and apparently they do.  The A.C. Ryan and Mad Dog power supplies use connectors with clips on them.  Then there's the cables themselves: Stiff.  And the 24-pin power connector was short in length and VERY stiff.

Here's the ends of the modular cables that would plug into your motherboard and drives.  Note the two piece 20/24-pin ATX connector.

The modular interface for the OCZ uses spade terminals. This adds a little more resistance than soldered on connectors, but clearly there would be no issue with shorting given the jackets over each spade.

Inside we see a whole lot of Topower goodness.  Note the large black heat sinks.

Despite being an "OCZ" "520W" made by "Topower," the ModStream is very different from the PowerStream 520W.

On the left, the ModStream.  On the right, the PowerStream.  It's clear that the ModStream is not a PowerStream with modular cables.

Clearly, the ModStream is no PowerStream.  But the PowerStream claims to have 6 independent rails, which means 6 seperate MOSFET's.  The ModPower, although powerful, has the usual 5 rails (or less) where lower voltages are used to regulate even lower voltages, making the capability of one rail completely dependant on the load of the other.  Not a bad thing IF the power supply uses quality components.

OCZ ModStream 520W +3.3V +5V +12V -12V -5V +5VSB
Max Output Current 28A 52A


1.0A 0.8A 2.5A
Max Combined Peak Wattage 260W 336W 12W 4W 12.5W
500W 28W


ATX connector 24-pin*
2 x 2 12V connectors 1
2 x 3 PCIe 1
6-pin Xeon/AUX connector 0
5.25" Drive connectors 4
3.5" Drive connectors 1
SATA Drive power connectors 2
Fan only connectors (thermostatically controlled 12V only) 0

With only four 4-pin 5.25 Molex connectors, it's clear that OCZ expects you to have SATA drives.  And one of the 5.25 cables only has one connector on it, which would probably be best for a second PCI Express card if you were to run SLI.  Given that there's also no fan only connectors, I can see doing a LOT of daisy chaining to get all of your lights and fans hooked up.   Think about it:  Even with SATA drives, if you use a molex for a second PCI Express card and two for your two optical drives, you're left with 1 connector for everything else.  Fortunately, there's FOUR interfaces on the power supply, so you could BUY one more cable or plug a fan power connector directly into the power supply.

There's a dedicated PCI Express cable and a dedicated SATA cable.  Having a dedicated SATA cable means you get the 3.3V that future SATA drives may use.

Results and Conclusion

OCZ ModStream 520W Zero Load Test One (367W) Test Two (302W) Test Three (430W) Full Load (620W)
12V 11.44 11.94 12.46 11.64 12.28
5V 5.32 5.09 4.99 5.13 4.91
3.3V 3.44 3.34 3.34 3.33 3.28
Efficiency 48% 76% 77% 73% 65%
Power Factor .53 .76 .77 .73 .65

Temperature under load = 16.7C. Peak temperature after power off = 48.8C.

Phenomenal!  Of course, when your expectations are "520W" load and you're given a 620W power supply (as per OCZ's own label,) how can you be let down?

At 620W the temperatures, despite the ever-quiet 120MM fan, never went over 18C.  Sure, the efficiency dropped to 65%, but if you're squeezing 620W out of this power supply for long enough periods that would allow a 65% efficiency to make a difference, then you're doing something with your PC that you shouldn't!

The voltage was stable during all tests.  The efficiency was good and the power factor was good for a power supply without active PFC.

Clearly, this power supply gets a 10 for performance.  It just can't get much better than this, and for just over $100, it's probably the best power you can get for the money.

For features, the power supply has some downfalls.  The modular connectors have all of the ugliness of the Mad Dog or A.C. Ryan with the ends of an Ultra X-Connect (no clips!)  They had stainless steel braiding and clear, UV reactive tubing over them making them stiff (although they looked cool under UV light.)  There wasn't many power connectors (even IF you use SATA drives,) but at least is was quiet and STAYED quiet even under a 620W load.  All said, the power supply gets an 9 for features. 

That means the total score for this power supply is 9.5 and we have ourselves another SLCentral editor's choice!  The PC Power and Cooling Turbo Cool 510 and the Ultra X-Finity 600W are in good company.

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