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OCZ GameXStream 850 Watt

With a history of catering to the enthusiast crowd OCZ has brought to market many great PSU’s. It’s newest offering comes in the form of a SLi certified 850 watt behemoth dubbed the GameXStream. With plenty of amps and active PFC this is not your father’s PSU.


Offensive linemen, teachers, dear ol’ mom, and power supplies. The one thing these all have in common is that they are all the unsung heroes of their fields. Often overlooked as their roles may not be as glamorous as others but without the solid foundation they provide everything built atop of them would quickly crumble to pieces.

When building a computer most of the attention goes to the stars of the show including the CPU, video card, memory and motherboard. Parts that can be shown off and command a certain amount of enthusiasm. But behind all the sparkle and shine, amidst none of the fame of those items is the one piece that makes it all possible; the power supply. Without a rock solid PSU your computer would quickly turn into an unstable beast of burden that at best restarts the computer in the middle of your frag fest and at its worst, dies completely damaging your motherboard and CPU with it. A good power supply can provide your system with clean solid power helping you to achieve those massive overclocks or simply to keep your gear working for many months.

And so I present you the OCZ 850 Watt GameXStream PSU. A no nonsense, get the job done at all costs power supply. With enough power to run even the most demanding gaming machine, this PSU has it where it counts. Housing a ton of amps, active PFC and a large 120 MM fan to keep it all cool the OCZ 850 Watt GameXStream looks good on paper. Looking good on paper also happens to mean squat when it comes to the real world. So let’s get to it.

The OCZ GameXStream 850 Watt PSU


OCZ Technology

OCZ is a company many of us are familiar with as they provide the very best products for a wide range of users. Starting with overclocked video cards and memory modules to power supplies and cooling products OCZ has earned the respect of hardware enthusiasts around the world (No easy feat).  For the rest of you who may not be familiar with the company I’ll let them tell you:

Entering the memory market in August 2000, OCZ Technology was built around the determination to manufacture the best high speed DDR and RDRAM. OCZ was founded by enthusiasts, for enthusiasts, and our commitment to the end-user has not digressed. OCZ Technology has been an innovator in many areas. We were the first manufacturer to make Dual Channel optimized memory available to the public, which originally took advantage of nVidia’s Twinbank or Dual DDR architecture, found in their nForce chipset. We have now taken that technology and tailored it for the Canterwood, and Granite Bay chipset’s. OCZ developed and was the first to implement ULN technology, which has been a critical element in our manufacturing process for some time. We at OCZ diligently work to improve communication with CPU and motherboard chipset manufacturers prior to the release of their products. Only in this manner can we fine-tune our memory’s SPD settings, ensuring a synergistic relationship between the memory module, memory controller, and microprocessor. In today’s rapidly evolving semiconductor industry, such communication is not simply research, but a necessary component of our manufacturing process.



  • NVIDIA® SLI™ Certified
  • Active PFC (Power Factor Correction)
  • 80% Efficiency rating at typical load
  • 4 Channel 12v output
  • 2 Channel PCI-E Connector
  • Dual CPU support
  • 120mm blue led fan for quiet operation
  • 3 year warranty



20+4 Pin Main x 1
This is the main connection that powers the motherboard. It has support for older boards (20P) as well as new generation boards (24P)



4+4 Pin CPU x 1
This connector powers the CPU. In 4+4 mode it can power two CPU’s (Dual Socket) or a single quad core (Single Socket). In 4pin mode (1 connector) it powers most of todays CPU’s


4 Pin Molex x 6
This connector powers PATA hard drives, optical drives and fans.

6 Pin PEG (PCI Express Graphics) x 2
This connector powers todays graphics cards. They provide an extra 75 watts each for a total of 150 extra watts.

4 Pin Floppy x 2
This connector powers internal floppy drives.

SATA x 6
This connector powers the latest Serial ATA drives.


With no shortage of connectors to be found you can trust that this unit will handle all of your hardware. Now let’s take a quick look at how the power is broken down in this beast.



OCZ GameXStream 850 Watt PSU
DC Output Specifications

Output Voltage Current (A) Regulation Ripple
Min Max
+5V 0.5 A 30 A +/- 5% 50mV
+12V1 0.5 A 20 A +6% / -4% 120mV
+12V2 0.5 A 20 A +6% / -4% 120mV
+12V3 0.5 A 20 A +6% / -4% 120mV
+12V4 0.5 A 20 A +6% / -4% 120mV
+3.3V 0.8 A 30 A +/- 5% 50mV
-12V 0.0 A 1 A +/- 10% 120mV
+5Vsb 0.0 A 3 A +/- 5% 50mV
Input Voltage 90Vac – 265Vac
Frequency 47Hz – 63Hz
Power Factor 0.99 Typical
Dimensions 152.4mm(W) x 139.7mm(L) x 85.7mm(H)


As rough and tough as power supplies can be (ever drop one on your foot?) I still like to check out how the company packages them to ensure their safety. The GameXStream came in a very thick and rigid cardboard packaging. This is pretty much the standard in the industry.

The Front


Turning the package around lets me know that this unit has some “sophisticated features”. Some of these include Active PFC, silent operation and their 3 year warranty.

The Back


Opening open the box reveals the entire contents along with further steps taken by OCZ to ensure the safety of their product. While many people may just get right to the power supply I like to flip through the product manual and catch up on the latest technology.

Internal Packaging

All in all a fine job on the part of OCZ to protect your new power supply. It’s nice to see a company take the extra step a wrap the PSU in bubble wrap, ensuring its safe arrival.



Inside the packaging you’ll find the PSU, manual, power cable and four screws for installing the unit. I was a little disappointed at the lack of zip ties included. It is a small annoyance but one that would have a big impact as you’ll see on the next page.

Package Contents


Take a look at the length of these cables. I have never seen connections this long. At their farthest point they measure almost FORTY inches long! Now you know why I was upset at the lack of zip-ties. Plan ahead with this power supply and route these cables as efficiently as possible or else you could end up with a mess of cables inside your case and that can wreak havoc on your temperatures.

Super long connections
(Click to enlarge)


Speaking of connections, the OCZ GameXStream comes with these quick-disconnect molex plugs. For anyone who has tried to wrestle the power plug from a hard drive or cd-rom drive in a cramped case these are a godsend. Simply squeeze the top and bottom tab and the plug will be pushed outwards making it very easy to remove.

Quick disconnect molex plug


The first thing I thought of when asked to review this unit was “Am I going to have to mount this thing externally and run the cables to the various components?” Well it seems I was way off! Check this out. It is the same size as the Antec Truepower 430 watt PSU. This is simply amazing that you can get this kind of power in a unit that will fit in 95% of the cases out there.

Left: Antec 430w / Right: OCZ GameXStream 850w


Switching to the back of the unit we see the honeycomb grill and the 120mm blue led fan. During operation this fan was extremely quiet and any sound generated by it could not be heard over the other case fans. As you may notice there is no switch to select input voltage as this PSU supports the full range and can adjust itself automatically.

Intake fan & Exhaust vent


Opening up this PSU is a simple affair but one that should not be taken lightly. A power supply is not a component that should be serviced by the user. There are high voltages inside that can remain after the unit is powered off. Only attempt opening up the unit if you are comfortable around electrical components and are familiar with the proper safety standards.

With that said there are four screws (marked by the red circles) that need to be removed before gaining access to the internals. In doing so you will be voiding your warranty so only do so if you absolutely must open the unit.

Opening up the OCZ GameXStream


Turning to the inside we start with the cooling system. A Protechnic Electric MGA12012HB-025 120mm fan controlled by an internal fan speed controller provides the cooling. Rated for a maximum of 2500rpm at 100% load with 38dBA and 17dBA at low speed settings this fan is sure to keep the PSU nice and chilly. At no point during testing did the fan have to reach its full speed. As a matter of fact at no time during testing was I able to discern an increase in speed or volume from the fan. Cool AND quiet, a nice combination.

Protechnic Electric MGA12012HB-025 120mm fan


Looking at the components of the power supply it is a straight forward setup. Inside we find the following items:

  1. Smoothing Capacitors – When we get DC rectified from AC, we find that the voltage is far from steady. Since electronic circuits need to have steady voltages, smoothing of the rectified AC is accomplished with this capacitor.
  2. Power Transformer – Computers require six different voltages to operate (+12v, +5v, +3.3v, -5v, -12v, and +5v of the standby mode). Because it’s not possible to pack two independent high-power regulators into a power supply, this component creates the various voltages required.
  3. Heatsink – Used to cool different components to prevent damage to the unit and ensures optimal performance.
  4. Output Wires – These are the wires that connect the various components of you PC to the power supply.
  5. Group Regulation Choke – When the current in one coil goes up, the voltage increase in the other coils due to this current is subtracted from the corresponding output voltages. This ensures an acceptable regulation of all output voltages in a wide range of loads.




Test Platform
Processor AMD Opteron 165 @ 2.7 GHz
Motherboard ASUS A8N-Sli Deluxe 1.2
Memory 2GB of Patriot DDR-500 @ 200 MHz
1GB of OCZ DDR-400 @ 200 MHz
Drive(s) 1 – Seagate 80GB Barracuda SATA Drive (OS)
1 – Samsung HD501LJ 500GB SATA Drive (Games)
Graphics 2 x Albatron GeForce® 8600 GTS running ForceWare 158.22
Cooling Thermaltake Big Typhoon with SilenX 18 dBa 38mm Fan
3 x 120mm Fans
Power Supply PSU 1: Antec Truepower 2.0 – 430 watts

PSU 2: OCZ GameXStream 850 watts

Display Westinghouse 37″ LVM-37W3
Case Coolermaster CM Stacker 830
Operating System Windows XP Pro SP2


How we test

Test Methodology

To break in the OCZ GameXStream 850 Watt power supply I would use it for several days in the above test system. Usage would range from surfing the web, to some gaming and some image editing. To establish load conditions we ran a variety of different processes on the test system to create as much power demand on the OCZ GameXStream as the components of the test system would allow.

All electrical measurements were measured using a new Radio Shack digital multimeter and a Kill-A-Watt power meter. You should never rely on software measurement applications as these readings can be very inaccurate.

As most of you are aware it is virtually impossible to drive an 850 Watt PSU to its maximum load capabilities using a standard test rig even with the number of components we have added to increase power draw. Unfortunately Bjorn3D doesn’t presently own an electronic load simulator to drive these devices to their maximum output. Hopefully we’ll have one of these devices in the not to distant future. While measurements taken using one of these devices show the true and ultimate capabilities of the power supply being tested, it’s not “real world”. By this I simply mean other than for bragging rights, why measure something you’ll never practically attain. The question then arises why buy a power supply that provides more than you need? Many Computer Enthusiasts subscribe to the premise that a power supply should never be driven in a real life environment to more than 75% – 80% of it’s capable output for obvious system performance reasons. I personally like a cooler quieter system so I feel the 60% – 70% range gives me more of a performance comfort zone.

With this test system we established two points of reference which we’ll refer to as Idle which ranges between 147 – 160 Watts and Load which ranges between 288 – 328 Watts. We attained these levels by applying various levels of overclocking coupled with running various applications in the background to stress the test rig to these demand levels.


Idle Results – Measured after a fifteen minute period of inactivity with no applications running and no open windows.

Load Results – Measured while running two instances of Prime95, looping 3DMark2006, transferring a 2GB file between disks, and playing a DVD.

Before I present you with the results I want to show you why it is important to take manual readings when testing the voltage output of each line and not rely on software. This screenshot was taken during preliminary testing when I was attempting to determine what my voltages were going to look like. At no point did any of the lines drop below their rated output (5v, 3.3v 12v).

Click to enlarge


Turning to the final results, we see the 3.3 and 5 volt lines are rock solid here for the GameXStream. The 12v lines may look like they are out of range with the ATX spec. A little research reveals that while the ATX standard specifies no more then +5% on the 12v line it also allows for a total variance of +-10%. OCZ allows for 6% on the plus side and 4% on the negative side complying with the ATX standard. So while these numbers may look a bit alarming I can assure you that at no time did I experience any incidents.

Results(V) Measured with Radio Shack Multimeter
Power Supply Antec TruePower 430w OCZ GameXStream 850w
Idle Load Idle Load
3.3v 3.4 3.4 3.37 3.36
5v 5.15 5.15 5.00 5.04
12v1 12.26 12.26 12.63 12.54
12v2 12.26 12.25 12.65 12.61
12v3 12.63 12.58
12v4 12.65 12.59
Wattage Used 160 w 328 w 147 w 288 w
PF 0.71 0.96
Ambient Temp 26.7 C
Exhaust Temp 38.0 C 41.9 C 30.3 C

33.1 C


Now take a look at the wattage used by the OCZ GameXStream. By doing nothing else then swapping out the PSU I was consuming forty less watts at load! This may seem insignificant but remember this is not an extreme system. For those of you that are running quad-core with dual 8800 GTX’s, moving to a more efficient PSU can have even more dramatic results and ease the shock of the electric bill each month.


I have been using the OCZ GameXStream for a little over a week now and have had a generally positive experience with it. I really like the fact that this PSU is more efficient then the previous one for two reasons. The obvious one is that my electric bill will be lower and that’s always a good thing and secondly, the heat output from the PSU is lower. Not that I mind it in the winter but having a small office turn into a sauna from the heat of the PSU, CPU and GPU is a little extreme.

Going into this review I had pre-conceived notions about what sort of value and level of performance this unit could provide. I am really excited to tell you that it met and surpassed all of my criticism. I never would have thought you could get this level of power in such a size and still remain quiet and cool, yet that is exactly what the GameXStream 850 did. At first I was concerned regarding the output on the 12v rails but after asking around and searching different forums the consensus was that the little extra output was nothing to worry about and in some cases welcomed. After more than a week of solid operation I can attest to the quality of this PSU.



850 watts may seem excessive to many of you but it is important to remember that this power supply offers so many more features than power output alone. With its high efficiency rating, active PFC and quiet operation this PSU has a lot to offer. Also, let’s not forget that only a couple short years ago people scoffed at the idea of 500 watt power supplies.


+  Active PFC
+  Silent operation
+  Fully sleeved cables
+  Cables length is enough for any case
+  Abundant power output
+  Superb value and performance
+  High efficiency rating
+  Fits in many cases


 Blue led fan may not suit your style
 2 – 6P PCIe won’t natively support 8800 GTX/Ultra SLi

Final Score: 8.0 out of 10 – A solid product delivered at a good price.


I’d like to extend my sincere appreciation to OCZ Technology for allowing me the opportunity to review this product. Through support of companies like these we at are able to provide you the community with quality reviews.

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