OCZ PSU Questions

msmalls74

msmalls74

msmalls74

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Im was looking for a new PSU, that could possibly used for Crossfire if required at a later date. Ive been looking at either the OCZ Stealthxstream 700W or the 700W modxstream, both are rated at 700W but the stealth has 4x12V rails and the mod has 2x12V. The current rating for the Stealth is 4x12VC @ 18W per rail,
http://www.ocztechnology.com/images/awards/sxs_700_pins.jpg
and the Mod has 2x12V rails rated at 25W, the Modxstream is rated for SLI. http://www.ocztechnology.com/images/awards/mxsp_wattage_charts.jpg
So which one would be better for crossfire in the future, to me the stealth has 4x18W (72W) and the mod has 2x25W (50W) on the 12V so would the stealth have more current available for the GPUs? On the power configs for the PSU it shows the Modx has 552 watts available on the 12V and the Stealth has 520W (675-155), so according to that the Mod has more current available on the 12V rails, can anyone help clear this up?
 
both are capable of handling cross fire. The question to ask is what other gadgets you want to run. Extra HDD's, disk drives fans and LED's will have an important afffect on what to choose. If you have many of these extras your looking for a 850w + in dual crossfire or 1kw min for any triple crossfire and even higher for the mobo's which support quad graphics cards! No matter which model you go for the GPU will still pulll the same power, if your looking for more upgrades in the future go for the modxstream. This is because it is one that i can vouch for as being stable to use even under intensive and prolonged periods. For ultimate quality though id take a look at the corsairs PSU's - the creme de la creme!
 
Nice mix of opinion and misinformation there Akempster.

I doubt there's much to call between the two. Neither will have independent 12V rails, neither will adhere to the stated specifications with great loyalty. I'd buy the stealth, on the grounds that one of my friends is using one and that I don't trust modular power supplies.

Which graphics cards do you have in mind?
 
so you complain about opinion and mis infomation, then state "i dont trust modular PSU's"?

Your right about neither having true seperate rails though. Also, I would go for the stealth extreme for the reasoning the OP has.

@Akempseter: totally depends on which cards he might crossfire, and if he doesnt have a lot of other things in his case, he is certainly not going to need 850w just to do crossfire, even with two 5870's since there TDP is what, 188w?
 
stulid said:
Oh dear!

I suppose that means my Antec new truepower 650w psu is rubbish.
Click to expand...

No that's just you twisting the words on what is essentially a personal preference and not a factual statement. Anyways nice PSU, rated very highly on Bit-tech's review.

In response to the OP, what cards are you looking to crossfire? This will help in making the judgement, i wouldn't fancy crossfiring 2 5870s on it but say 2 5770/50 you might get away with. Might help to do a bit of specific research on each PSU as i'm in a similar boat looking to crossfire 2 5770s but it's looking unlikely.

EDIT: personally i would go stealth as modular/non-modular has no influence on me, i find you can get the same results in terms of tidyness with a bit of work. I wouldn't say there's a lot between them to be honest.
 
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There's nothing wrong with either of the 700s, it'll handle a 2-card crossfire absolutely fine unless you stack the case full of optical drives, fans, lights and anything else you can find.

Take the Modular if you've got a fairly cheap case (anything under the antec 900), or the stealth if you've got a case with lots of hidey holes for getting rid of the cables.
 
Ch3m1c4L said:
so you complain about opinion and mis infomation, then state "i dont trust modular PSU's"?
Click to expand...

Any plug/socket arrangement used in computing features pieces of copper push fitted together. This means resistance, which with a voltage applied means heating. That encourages oxidation, which increases resistance, which increases heating. It also means lower efficiency.

I'm happy to concede that I know of zero electrical fires that can be attributed to modular power supplies.

Introducing an additional point of failure in any system for aesthetic reasons is not something that sits well with me. Hence I don't trust them, and won't use them.
 
JonJ678 said:
Any plug/socket arrangement used in computing features pieces of copper push fitted together. This means resistance, which with a voltage applied means heating. That encourages oxidation, which increases resistance, which increases heating. It also means lower efficiency.

I'm happy to concede that I know of zero electrical fires that can be attributed to modular power supplies.

Introducing an additional point of failure in any system for aesthetic reasons is not something that sits well with me. Hence I don't trust them, and won't use them.
Click to expand...

So, the connections over time (I'm assuming lots of time) will oxidize, causing more resistance and as such more heat, and therefore = bad?

I thought the pins on the connectors would be plated/made out of something else? Molex connectors aren't copper? I know the wires are themselves :P

I suppose sata ones are though, but wouldn't the mere act of unplugging and plugging back in "scrap" the oxide off the connecting surface, and as such negate this? I would have thought if it got enough to cause a significant amount of heat, it would also have been enough to cause some strange behavior on your PC. But aren't we talking like, a lot of years here, since otherwise sata cables and the physical connectors on components that you connect the PSU to would suffer the same degradation?

Just like to point out, I am in no way saying you wrong, i just want more info on it :)
 
Both my modular PSU's work just fine, including the Modstream Pro!! I've monitored the output for a while now and no decearnable loss of performance so far.

To get back to your original OP question.

Either of the 700w PSU's will do the job. I run a HX1000 with my xfired 5870's but in all honesty it's a little overkill. But with all the other drives and bits I've put in recentley it gives me a larger overhead to play with in the long term.

Just consider the case that it's going to fit into and the room for cabling etc. Note that the fixed cables on the OCZ PSU's (both the ones you mention have fixed cables for at least 24 pin ATX and 8 pin cables) can be a little short so factor in the possibilty of having to get extension cables dependent on cable routing and MB socket locations. :)
 
The contacts might be nickel plated copper or just aluminium, as I don't have a modular psu I'm not sure. The principle stands though I can't imagine nickel oxidises terribly quickly, an electrical connection that relies on contact pressure only isn't a good thing. We're pretty much stuck with it between motherboard and cable, though a few people solder that connection. There will be a voltage drop across the join, and this will mean heat.

With a psu that was made to sensible tolerances I can't imagine it's an issue, but manufacturing faults invariably occur, as does user error. Cables working loose with time leading to poorer contact is the likely example of the latter, manufacturers trying desperately to bring a product to market at a competitive price (atx psu's being ludicrously cheap compared with industrial supplies) can easily lead to poor manufacturing.

That I can't find examples of computer fires attributable to this strongly suggests it's negligible, or possibly that it's a figment of my imagination. Regardless, negligible increase in risk for cosmetic gain is an easy decision, only encouraged by modular power supplies attracting a price premium. I'd rather the already stretched manufacturers budget went on components than on a set of connectors.
 
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