Corsair RM550x Power Supply Review

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Nintendork

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We really need more platinum/titanium PSU's at 300-500w. Most PC's stays near idle and with the efficiency focused gpu's/cpu's they rarely exceed 100w unless you tax them.
 

turkey3_scratch

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Plus companies often don't even send you the rebates, sometimes they just say it was too late or some other bull crap like that. I agree with Blackbird. I've been waiting for a review of the 550 RMx, and what I get out of this review is that it trades blows with the 550 G2 that saying one or the other is better is just silly and extremely nit-picky. They are both incredible. Both offer a 7 year warranty, as only higher-wattage G2s offer the 10 year warranty. They are just so close, that when it comes to picking the better one, the cheaper one is better, and the G2 is cheaper.

I've actually quit including rebates in my pcpartpicker lists. They are a pain and I don't think they reflect the true cost of an item.
 

turkey3_scratch

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I wish so, but unfortunately if this were to happen they would end up priced the same as any Platinnum/Titanium 650W unit. It's just the way it works. Quality low-wattage models are priced almost the same as the higher-wattage models. I would like to see something like a Titanium 250W model come out from Seasonic. Something like $40, fully modular. Will never happen, though.
 

logainofhades

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Yea the price for these is a big turn off. It is selling at a price that the Evga G2 750w is often seen at. The Evga P2 650w even sells for less. There are quite a few Seasonic and Superflower based units, cheaper than this, actually.
 

logainofhades

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The cheapest RM550x is $99, before rebate, at newegg. You can get a G2 and P2 Evga for same or less. Seasonic 550g is selling for $69. Even if I needed a fully modular unit, there are less expensive models from Evga, XFX, and Antec. For a few $$ more, I can get a GS 850w or a G2 750w. The pricing on this unit is just not good enough to compete. Even their own 650w RMX is only about $10 more.

http://pcpartpicker.com/parts/power-supply/#e=5,4&W=550,2000&sort=a9&page=1&m=52,11,14,71,39&p=1,2
 

turkey3_scratch

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Yes G2 hold-up time is 12ms whereas ATX spec is 16ms, but that doesn't mean the PSU is going to cause damage to the computer, it just means that if there is AC loss for 12ms the computer will shut down, as the PSU won't be able to maintain the DC. Better hold-up time is not worth the additional $20, especially if you're not running something like a server, in which you would have a UPS anyway that quickly kicks on the battery power in 12ms or less (you'd do research to buy one that does so, as some may be higher than 12ms).

I'd say the hold-up time is a small gripe and not enough for a $20 more PSU. If hold-up time as super important, every PSU reviewer site would test it like Jonnyguru.
 

powernod

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Better hold-up time is not worth the additional $20, especially if you're not running something like a server, in which you would have a UPS anyway that quickly kicks on the battery power in 12ms or less (you'd do research to buy one that does so, as some may be higher than 12ms).
Indeed, those who have a good UPS to protect their system, they shouldn't worry about that, but if you don't have a UPS, this failure at Hold-UP time /Power-OK signal, could be very dangerous.
 

turkey3_scratch

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How would hold-up time be dangerous?
 

powernod

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I didn't say only Hold-up Time, I was referring at Aris's new test for Power-OK signal. Take a look of one of his analysis : " The hold-up time tests don't go well. Not only is the measured hold-up less than 16ms (the ATX spec's minimum), but the Power_OK signal drops after, and not before, the PSU's rails go out of spec. This means that your motherboard gets a false power-good signal from the PSU. Indeed, we measured the +12V rail floating at around 10.8V when Power_OK dropped to zero. This is a very low voltage level that applies lots of stress to the voltage regulators of components fed by +12V " ( http://www.tomshardware.com/reviews/super-flower-leadex-gold-550w-power-supply,4416-4.html )
 

turkey3_scratch

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That is the Superflower Leadex 550W where the Pwr_OK signal drops after the voltage is below 10.8V, and while the EVGA 550 G2 is based off that unit, Aris does not mention that same behavior for the G2 on the 550 G2 review. So it is possible the 550 G2 does not have this same mistake, but I am unsure myself. They could have made modifications.

Edit: Ahh, he didn't check AC loss to PWR_OK in the G2 review, so the behavior is most likely still present.
 

turkey3_scratch

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This behavior is also present on Sirfa-made units, which have very high AC loss to PWR_OK off hold up times because their PWR_OK signal does not turn off until the voltage is somewhere below like 10.2V! http://www.jonnyguru.com/forums/showthread.php?t=12886

The real question though is how fatal, in terms of the 550 G2, this really is. Is the 10.8V+ applied to the unit's VRM components for 12ms really going to harm the unit fatally? If anything, those Sirfa units are more dangerous. A higher AC loss to PWR_OK loss time is not necessarily good if the voltage is too low. They should be setting the threshold to 11.4V, not these lower values, so shame on Superflower and Sirfa for this. But it's actually a good thing the 550 G2 is only 12ms, you don't want those low voltages to be handled by the 12V VRM components for any longer, shorter is better in this case. But yes you are correct, they should improve these, but again does this merit the $20 extra for the 550 RMx? I'd have to ask a PSU expert how much of a harm this 10.8V+ for 12ms will make, as I'm not an expert on that.
 

Aris_Mp

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hold-up time tests are not the easiest thing to do since besides extra equipment you also need GOOD knowledge of what you are doing. On top of that in order to measure hold-up time along with power good time and other stuff as well you need an accurate (thus expensive) four channel, at least, scope. Till I raised enough money to buy one I didn't have the capability to measure both hold-up times so I provided only the power good signal's time.

If your PSU has a really short hold-up time in some cases your UPS won't be able to handle the job, especially if its transfer time is higher than 15-20ms. Moreover the longer the PSU goes without power, the larger the in-rush current it will draw when it has power again. This means that its bulk caps will be almost empty so the In-rush current could exceed the current handling capacity of the UPS and cause its shut down. This means that a PSU's hold-up time IS important!
 

turkey3_scratch

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Aris, you say the in-rush current could exceed the current handling of the UPS, don't you mean the PSU? And are you the Aris who wrote the article? Also, if the in-rush current exceeds the current handling capacitor of the bulk caps and the unit shuts down, will that cause hardware damage at all?
 
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