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Thread: Platimax 1200W or Platimax 1350W or MaxRevo 1350W?

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    Default Platimax 1200W or Platimax 1350W or MaxRevo 1350W?

    I’m deciding between the 1200-Watt Platimax EPM1200EWT and the 1350-Watt Platimax EPM1350EWT. (The MaxRevo in the title is a mistake I can't change.) I’ll base my choice on total wattage, the AC input voltage range, and the rails’ output rating.

    The online EPM1350EWT manual shows it has two 12V rails, 12V1 and 12V2, at 0-20A output rating and four 12V rails at 0-30A output rating. The 20A rails are used for parts of the motherboard’s 24-pin and 8-pin headers only. The other four rails cannot be used to connect to the 24-pin MB header. One of the other four rails can be used to connect to the 8-pin header; I’ll get to that later. The EPM1200EWT has all six of its 12V rails at 0-30A output rating. I prefer the 30A rails for the MB, but I also prefer the higher wattage PSU.

    The EPM1350EWT has a modular cable with two split ends. The PSU end is split into 20-pin and 16-pin connectors. The 20-pin PSU socket contains all of the 12V1 rail’s pins plus some non-12V pins. The 16-pin PSU socket contains all of the 12V2 rail’s pins plus some non-12V pins. The MB end is split into the usual 24-pin and 8-pin connectors. I don’t know which 12V1 and 12V2 wires go to which MB header or if there is a mix of both rails' wires going into each MB headers.

    Because I don’t know the power distribution of 12V1 and 12V2 relative to the MB headers, I can only generalize. 12V1’s 20A plus 12V2’s 20A makes 40A. Power = Current x Voltage = 40A x 12V = 480W. The 480W ceiling of 12V power going to the MB seems low. I’ve heard that modern CPUs and video cards take all their power from 12V. A 125W CPU, 3 high end video cards, and a high end motherboard uses a lot of power. Although some of the video card’s power can come from the PCI-E cables from other rails, up to 75W of the video card’s power can come from the PCI-E slot, whose power comes from 12V1, 12V2, or both. Three video cards plus the CPU take (3 x 75W) + 125W = 350W of 12V power from the MB. Adding a fourth card would draw another 75W from the MB, making it 425W. This is before considering RAM, USB devices, fans, MB’s power. Though I don’t know which of these uses 12V, I’ve heard of software that enables compatible USB ports to charge devices over 5V. If the MB has 4 of its PCI-E x16 slots, all its USB ports used, and all components under 100% load, the total power draw from the two 12V rails may exceed 480W, meaning 20A is exceeded on one or both rails. Can the 3- or 4-card system break the rails’ 20A limits?

    Is it part of motherboard standards for the 8-pin header to be the only power source for the CPU? If not, then is there a standard for MB power distribution? If there’s no such standard, then wouldn’t the following be possible bad scenarios?

    Example A – One 12V 20A rail per MB header, and MB’s 8-pin as CPU’s only power source:
    If the 8-pin’s 12V power uses only the 12V1 rail and the 8-pin header powers only the CPU, then the 24-pin’s 12V pins use only the 12V2 rail, which must provide 3 x 75W = 225W for 3 video cards alone. More than 15W of anything else pushes 12V2 above 240W.

    Example B – Mix of 12V 20A rails in each MB header, but unbalanced power draw:
    If a mix of 12V1 and 12V2 wires go into the 24-pin MB header, a mix of 12V1 and 12V2 wires go into the 8-pin MB header, the 8-pin header draws most of its power from the 12V1 wires, and the 24-pin header draws most of its 12V power from the 12V2 wires, then the result has almost the same problem as Example A’s.

    Revisiting earlier comment on other rails:
    One of the other four rails (the 30A rails) can be used to connect to the 8-pin MB header, but I don't know how much that relieves the load from the 12V rails going into the MB 24-pin header in the cases of uneven power distribution.

    Disparity between maximum output rating and OCP trip point:
    Although the over-current protection (OCP) trigger range for all the rails for both PSUs is specified as 40-50A, I don’t know if this means the EPM1350EWT’s 20A rails can handle sustained usage between 21A and 50A (or whatever the exact trip point is). From a marketing standpoint, I don’t see any reason the rails have a rated output less than the OCP trip point unless (1) it cannot sustain currents, safely or without wearing itself out too soon, between the maximum rated output and the trip point; or unless (2) the rails were designed to handle sustained usage up to the OCP trip point in case novice users tie many things to one rail, whereas the lower output rating is there to assure the amps-sensitive users that their mobos won’t get fried. The problem with the latter rationale is that it would be over-applied for the EPM1350EWT’s 12V1 and 12V2 rails but not for the corresponding rails on the 1200W or the 1500W Platimax, which are rated for 30A. I don’t see any reason the EPM1350EWT will have the exact same OCP trigger ranges as the other two Platimax units but a lower rated output on 12V1 and 12V2, unless those two rails aren’t as heavy-duty as the other two units’. Any thoughts?

    AC Input voltage range concerns:
    The EPM1350EWT has a narrower AC input voltage range of 110–240VAC compared to the EPM1200EWT’s 100–240VAC. My non-Enermax PSU has a range of 100–240VAC. So the EPM1350EWT’s range looks odd. I live in the US, which uses 120V +/- 5% (114–126V), but I’ve heard the actual figure is closer to 117V. I don’t know if that’s before or after considering the 5% margin. If it’s before, then 117V +/- 5% would be 111 – 123V. 111V is too close to EPM1350EWT’s 110V floor. Even though the EPM1350EWT’s manual prints a maximum range of 100–264VAC, it is printed in parentheses besides the range of 110–240VAC. I don’t know if this means this PSU can’t handle sustained usage at 100-109VAC. On the other hand, the EPM1200EWT has a maximum range of 90-264VAC.

    Which unit should I get? Thanks.
    Last edited by Cyan; 12-04-2013 at 04:00 PM.

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    As for the rails: You have six of them. You're not going to overload any of them even if they're all 20A. The 8-pin only provides power to the CPU.

    As for the AC input range: 110-240VAC is a liberal spec. So 111V isn't going to stress it out. It's designed to accept 110V continuously. They're worried about the primary circuit taking in the CURRENT, not the voltage, at higher wattages. For example: I'm sure 100V input is no issue at only 1000W of output power because the input current is lower. See what I mean?

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    @Cyan:

    I won't quote your post, because it's probably the longest one I've seen in last year or so

    You've stated your concerns, but you didn't state your rig specs, which would help a lot in solving your dilemma

    Usually modern boards come equipped with a double EPS or 8pin + 4pin (or even 6pin) connectors that absolutely resolve any kind of questions about CPU/MBO power distribution and supply.

    In any case, even if you only have 24pin + 8pin connectors at your disposal, they are more than capable to supply very demanding kind of rigs (even 3-way SLI without huge OC). Someone tested awhile ago 8pin connector with more than 300W and it was easiliy pushed through.

    Modern components draw power mostly form the 12V rails but they use the minor ones too (in a smaller amount of course).

    Absolutely accurate OCP points on every rail isn't easy to achieve because of the used components in PSU's (and their stated tolerance, for ex. 5%) so you can't expect from any of the mentioned manufacturers to state that their product will shut down at exactly 20.0A or 25.0A. Those are the "minimum" max values that they can push through, but true values are most definitely above those.

    Usually there is some headroom in their declared absolute maximum values (OCP trip points) and that can be anywhere between 10-100% above the official numbers. In any case it's more than enough to push even most demanding modern rigs.


    The input voltage isn't a problem too, because those PSU's can easily run even at 100V (or even below that) and if you use the proper AC cable supplied with you PSU it shouldn't be any problem.

    The problem could arise if you would choose to use a smaller gauge AC cable and decide to pull above 1500W AC from the wall socket (with US voltage). That smaller gauge wire has greater electrical resistance and with lager amount of power it would need a lot of current because of the Vdrop over the AC cable.

    But again, if you use proper wiring it will not be a problem.

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    Cyan (04-18-2013)

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    Thanks for the replies, guys!

    Quote Originally Posted by jonnyGURU
    You're not going to overload any of them even if they're all 20A. The 8-pin only provides power to the CPU.
    If the 8-pin uses one 12V rail and the 24-pin uses another 12V rail, and if three PCI-E cards draw 75W from the slots each, then is the rail for the 24-pin responsible for providing 225W for those cards? If so, then wouldn’t that rail’s power draw already exceed 240W (given 15W of anything else, like other mobo components, USB charger, or a PCI-E x1 card), and therefore 20A?

    Quote Originally Posted by ferky
    Someone tested awhile ago 8pin connector with more than 300W and it was easiliy pushed through.
    By any chance, was this test for the EPM1350EWT? If not, I still have the concern directly above the quote ^.

    Quote Originally Posted by ferky
    but you didn't state your rig specs
    -hex-core AMD, 125W
    -6 drives
    -PCIe add-on card
    -planning to get GTX 690 or Titan. Might get SLI or a workstation card.

    Putting all this into the online PSU calculator (Enermax website also uses this calculator); a GTX 690 plus Quadro 6000; choosing high end desktop; high performance fans (3 x 120 mm and 2 x 140 mm); an LED fan (1 x 250 mm); a fan controller (comes with the case); 5 USB devices; 100% CPU utilization; 100% system load; and 30% capacitor aging (calculator recommends 20-30% for 24/7 and 1+ years use); it recommends 1191W. This calculator doesn’t give the option of USB charging devices (the Asus AI Charger can charge iPads, which take more than the normal USB wattage). This is awfully close to 1200W, which is why I want 1200W or higher PSUs. The calculator recommends 1294W for the dual GTX 690 variant of this system. Do I need a 1300W+ PSU?

    I know lots of people say 1200W is overkill and that I am unlikely to have the entire system under 100% load or have that much capacitor aging, but I think I only need to have the entire system under 100% load once or reach that level of capacitor aging once to go over (or not go over) the PSU wattage limit. So, I’d rather have and not want than want and not have, at the worst possible time.

    Although my OP asked about using 3 or 4 video cards, I am unlikely to use that many on my current mobo. Because video cards usually take up 2 slots, my mobo only has room for 3 video cards or 2 video cards plus one PCIe x1 or x4 card. But then again, if the PCIe x1 or x4 card can also take 75W from the slot, then my OP isn’t moot. In any case, I’d still like to move this PSU to future mobos, which might have the spacing for more cards.

    Quote Originally Posted by ferky
    Usually modern boards come equipped with a double EPS or 8pin + 4pin (or even 6pin) connectors that absolutely resolve any kind of questions about CPU/MBO power distribution and supply.
    Yeah, my mobo has EATX 24-pin, EATX 8-pin, EATX 4-pin, and a molex header. The 24-pin and 8-pin require connection. The others are optional. The mobo manual says the EATX 4-pin helps stability in overclocking, so I don’t know if the EATX 4-pin’s extra power can go anywhere outside of the CPU or RAM. The manual says the molex helps stability in having multiple video cards, so I don’t know if the molex’s power can go anywhere outside the PCI-E slots. In any case, it doesn’t say anything about power distribution. The EATX 4-pin or molex headers wouldn’t know anything about the PSU’s rail amperage limit. I think this is only made worse by the fact that most PSUs are single mega rail, so I don’t know how much Asus would focus on making even distributions and treating every mobo header as if each header’s 12V power came from a separate rail. For all I know, the 4-pin and molex might only start drawing power after the 12V1 or 12V2 rail far exceeds 20A. Any thoughts?
    Last edited by Cyan; 12-04-2013 at 04:09 PM.

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    Quote Originally Posted by Cyan View Post
    Putting all this into the online PSU calculator (Enermax website also uses this calculator); a GTX 690 plus Quadro 6000; choosing high end desktop; high performance fans (3 x 120 mm and 2 x 140 mm); an LED fan (1 x 250 mm); a fan controller (comes with the case); 5 USB devices; 100% CPU utilization; 100% system load; and 30% capacitor aging (calculator recommends 20-30% for 24/7 and 1+ years use); it recommends 1191W. This calculator doesn’t give the option of USB charging devices (the Asus AI Charger can charge iPads, which take more than the normal USB wattage). This is awfully close to 1200W, which is why I want 1200W or higher PSUs. The calculator recommends 1294W for the dual GTX 690 variant of this system. Do I need a 1300W+ PSU?

    I know lots of people say 1200W is overkill and that I am unlikely to have the entire system under 100% load or have that much capacitor aging, but I think I only need to have the entire system under 100% load once or reach that level of capacitor aging once to go over (or not go over) the PSU wattage limit. So, I’d rather have and not want than want and not have, at the worst possible time.

    Although my OP asked about using 3 or 4 video cards, I am unlikely to use that many on my current mobo. Because video cards usually take up 2 slots, my mobo only has room for 3 video cards or 2 video cards plus one PCIe x1 or x4 card. But then again, if the PCIe x1 or x4 card can also take 75W from the slot, then my OP isn’t moot. In any case, I’d still like to move this PSU to future mobos, which might have the spacing for more cards.
    Those power numbers, with the rig you specified, are extremely unlikely. In short terms, you would have to heavily OC your entire system and use every single component in you computer at the same time, which is practically impossible.

    I'm talking from experience because there is a watt meter at my desk that measures consumption at all time.

    My rig is based on a Intel i7 3930K @4.9GHz, OC Asus Rampage IV Extreme MBO, two heavily OC GTX680, 5 drives, 11 high perf. fans, PCIe x8 RAID card, and a bunch of other stuff like bluetooth/USB chargers/peripherals/sound devices etc.

    The maximum number was around 700W pulled from the 80Plus Platinum PSU (or 800W from the wall socket when you add PSU loss in efficiency). This was measured with a heavy load on both VGAs, CPU, cooling and disk system at the same time and it is extremely unlikely to go beyond that with your type of configuration (even with dual stock Titans).



    Yeah, my mobo has EATX 24-pin, EATX 8-pin, EATX 4-pin, and a molex header. The 24-pin and 8-pin require connection. The others are optional. The mobo manual says the EATX 4-pin helps stability in overclocking, so I don’t know if the EATX 4-pin’s extra power can go anywhere outside of the CPU or RAM. The manual says the molex helps stability in having multiple video cards, so I don’t know if the molex’s power can go anywhere outside the PCI-E slots. In any case, it doesn’t say anything about power distribution. The EATX 4-pin or molex headers wouldn’t know anything about the PSU’s rail amperage limit. I think this is only made worse by the fact that most PSUs are single mega rail, so I don’t know how much Asus would focus on making even distributions and treating every mobo header as if each header’s 12V power came from a separate rail. For all I know, the 4-pin and molex might only start drawing power after the 12V1 or 12V2 rail far exceeds 20A. Any thoughts?
    Those connectors are more than capable of supplying your configuration, even with most demanding graphics card on the market (which pull most of their power from 6/8pin PCIe connectors on the PSU).

    The power (current) distribution is covered with the basic electrical law - Ohm law. The current will flow through wires where the electrical resistance is lowest. So you won't go near 75W on PCIe slots, because a very big amount of current will come directly from the PSU (6/8pin PCIe).

    To max out MBO slots and its power delivery you would have to get 3 massively, world record benchmark breaking, overclocked Titans, which in start isn't practical and possible without some heavy duty cooling solution (like water, dry ice or liquid nitrogen cooling).

    In other words, your computer will overheat (without extreme cooling) way sooner before you could reach power limits of mentioned power supplies or MBO voltage/power regulation.

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