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OCZ ModStream 520W PSU OCZ ModStream 520W PSU: With one solid PSU line under their belt, we look at a modular one and see how well it holds up.
Date: December 26, 2004
Written By:

PSUs haven't really changed much over the past several years. Other than form factor changes and increased power output, a typical PSU today isn't that much different from one of five years ago. We may get UV covers and cables, LED lights, but generally, you stick one into your case and plug in the necessary power cables and pray you didn't buy a bunk one that will fry your system.

With system cooling becoming more of a challenge to manage, it's strange that it wasn't until recently we've began seeing more modular PSUs. The basic goal of these PSUs is to reduce clutter from cables by hooking up only the cables you need. The purpose is to eliminate not only the unsightly leftover cables typical in a PC setup, but to also improve system airflow by having fewer cables obstructing case fans.

We've already looked at a few modular PSUs from Antec and Ultra Products this past year, and today we take a look at OCZ's offering. Their PowerStream line was quite impressive when we last looked at it, so let's see if their continues to build on their PSU reputation.

While the PSU is modular, OCZ dubs this EZMod technology, which is their name for the technology. The OCZ ModStream differs from the last modular PSU we've looked at where the primary ATX power cables are attached to the PSU. The Ultra X-Connect we reviewed earlier this year was fully modular and had all its cables "detached". Like the X-Connect, the OCZ ModStream is polished to a brilliant shine.

While we knocked the ModStream for not being fully modular, this is not really a big deal to be honest as the main ATX cable(s) and the +12V connection are all required for most PC setups, saving you time attaching cables to the PSU that you already need. Note that there are two cables for 20 and 24-pin connections, rather than a single 24-pin connection and 20 pin adapter. I suppose this is the only real flaw in not making these cables modular as at this time, the extra four pins are not required for Athlon motherboards.

For cooling, OCZ took the silent approach (not truly silent, but relatively silent) to cooling. The rear of the PSU features a diagonal grid screen to allow air to exit the PSU. Since the entire rear is perforated, quite a bit of hot air is allowed to pass, and while a rear fan will accelerate airflow, it would be a noisier solution. The 120mm blue LED fan is the ModStream's intake fan that draws air in from the system and out the back. Overall, under our testing environment, the setup works as advertised, with little noise and warm (not hot) air coming from the back.

In a separate box, OCZ packages the rest of the cables needed for most installations as well as a manual (very well written I may add), zip ties and Velcro wraps for cable management, and a modded (modded for a PSU anyway) power cable. The EZMod power cables included with the ModStream are: One cable with two SATA connections; one PCI Express 6-pin connector; one point-to-point 4-pin cable; two dual 4-pin cables; one 4-pin (Molex) and Floppy cable. All the EZMod cables are EMI shielded (discussed shortly) and UV ready assuming you have the required lighting.

The OCZ ModStream isn't all about the bling though, as the unit itself features all the modern features enthusiasts demand out of their power supplies. The unit we received is rated at 520W (620W peak) and their "entry" model is rated at 450W (550W peak). For those of you outside North America, the PSU features Active PFC, but all models have OCZ's PowerShield EMI Control Technology (copper shielding to reduce electromagnetic interference) and a 3 year PowerSwap replacement program.

The ModStream feeds 336W on the 12V rail, and 260W on the 5V and 3.3V rails. OCZ has built the unit so that if your requirements are higher on the one rail, such as the 12V rail (water cooling and the like) the overhead is available, likewise, if you require additional 5V appliances (PC Cards etc.), there is overhead available on that rail as well.


MSI 915P: Intel Pentium 4 560, 1GB Corsair DDR2, 2 x Seagate 160GB, Seagate 120GB, MSI X800XT, MSI 16X DL, AOpen CDRW 52X, Koolance PC3-720SL.

To load up the system, we run Prime95 run for 20 minutes, with Folding @ Home running in the background, as well as ripping Jet Li's Hero DVD to the Seagate RAID setup. Voltages were monitored with ABRA DM-9700 multimeter. The comparison PSUs are the Ultra X-Connect 500W PSU and Cooler Master's RealPower 450W. The P4 560 will be clocked at 18x215 for all testing.


OCZ ModStream
Ultra X-Connect
CM RealPower


OCZ ModStream
Ultra X-Connect
CM RealPower

All three PSUs did well in our tests, with the RealPower being the most consistent throughout testing. The ModStream was hit hardest on the +12v rail compared to the other two, but was a bit stronger than the X-Connect in the +3.3v and +5v tests.

While we never felt the PSU would make a big impact on system and CPU cooling, the location of most PSU fans warrant a quick check.

System (°C)
CPU (°C)
OCZ ModStream
Ultra X-Connect
CM RealPower

The ModStream is on par with the RealPower which isn't too surprising since their cooling setup is almost identical. Despite the dual fans on the X-Connect, its cooling performance lags behind the other two by a couple degrees.

Final Words

Overall, OCZ has done a fine job with the ModStream 520W PSU. While it didn't lead the pack in performance, the results put it just behind the best PSU we've tested this year, so there's no shame in finishing second. Being a modular setup, installation was very easy, and although the PowerShield EMI made for stiff cables, we did not find them as difficult to work with as the X-Connect's.

There are just a few minor issues we had with the ModStream. Although the peak capacity is fairly high, we were a bit puzzled why OCZ left out some of it's more advanced power management features such as dual +12v rails and adjustment knobs that made us such big fans of their PowerStream series. Also, while we think it isn't necessary to make the PSU completely modular, we felt the extra 4-pin connection for most new Intel boards could have been an EZMod cable.

That being said, the ModStream proved to be very reliable though since we've only been using this for two weeks (about 12 hours a day on average) it's impossible to gauge the long term reliability. The 3 year warranty OCZ provides does ease our minds though, and with the cooling and power performance, as well as its modular capabilities, the ModStream is worth consideration if you're in the market for a new PSU.

Pros: Stylish design, reliable power, good quality EZMod cabling. Quiet and efficient cooling.

Cons: Not 100% modular, no dual +12v rails.

Bottom Line: While we wouldn't call this our PSU of the year, the ModStream is definitely on our short list. It has the aesthetics and reliability that enthusiasts desire, and is backed by one of the best warranties in the business which demonstrates OCZ's confidence in their products.

Hit us up in the Forums if you have any questions.


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