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+12 volt rails
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saxman2k
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9. November 2009 @ 18:44 |
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28 product reviews
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9. November 2009 @ 21:40 |
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Not sure what you mean by "+12 volt -12volt amperage", because Volts is the unit for Voltage (V), and amps is the unit for Current (I). To get Amperage you divide Power (W) by Voltage (V). The 2 +12 volt rails are pretty much 2 single voltages provided by the PSU (relative to ground of course).
I'm not that knowledgeable on the connectors. The PSU has 1 6-pin connectors, and GPU says 2 x 6 Pin. I would imagine that you only need 1 x 6 pin connector, and that the other one is a backup, but you'll have to wait on someone more knowledgeable on the connectors. The minimum system requirement on the card is 450W, so 500W should be enough. However the maximum card power(w) is 141W, so I'm guessing if the card is using 141W, it may cause some system instability with the PSU.
This message has been edited since posting. Last time this message was edited on 9. November 2009 @ 21:50
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9. November 2009 @ 23:45 |
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I believe you have made a mistake.
According to the EVGA web site (FAQ ID #58052), this graphics card requires a minimum of 26 amps of current at 12-volts. Your power supply has two 12-volt outputs (rails), each with a maximum current rating of only 18 amps. Neither of the two output rails is capable of supplying the 26 amps your card requires. EVGA also says you need two 6-pin power connectors. Your power supply only has one.
As for volts and amps, think of volts as being akin to water pressure and amps similar to water flow. For a given water pressure (voltage) a given hose (output rail) can only pass so much water (amps). Your card requires 26 liters per hour (forgive the rough analogy), but your power supply only has two output hoses, each capable of only 18 liters per hour. Unfortunately, you can't connect both output rails to your card without using adapters which are really only short-term solutions.
What you need is a power supply capable of supplying at least 26 amps to each of its output rails. And don't forget that you have other resources in your system that need 12-volt current, so you will end up needing more than just the minimum 26 amps your card requires. That's why EVGA recommends a minimum 450-watt power supply, the card alone takes over 310 watts.
Some power supplies (like yours) have two 12-volt output rails each with their own maximum current capability, while other supplies have just one large 12-volt output rail. Multiple-rail supplies are usually cheaper, but you are limited to how much current you can draw from any one of the rails. Single-rail supplies are usually more expensive, but you don't have to worry about trying to balance your load between multiple outputs--everything runs off one big hose (so to speak).
cee43ja1's recommended PSU--a modular dual-rail 520-watt Corsair--is a good one, but each rail is only rated at 18 amps. If it were me--and if you don't mind non-modular wiring--I would look for a single-rail power supply rated for at least 40 amps on its single 12-volt output rail. Something like this: http://www.newegg.com/Product/Product.aspx?Item=N82E16817139004 This will cost you $80 as opposed to $50 for the one you chose, but it is a high-quality PSU that should handle most of your needs.
Dick
This message has been edited since posting. Last time this message was edited on 10. November 2009 @ 00:41
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AfterDawn Addict
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9. November 2009 @ 23:57 |
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you will need both power connectors, and adaptors should not be used long term.
if you can return the ocz, do it, and get something like the corsair HX520/VX550.
with multiple 12v rail power supplies, you add up each 12v; the ocz you have has two 12v rails, with each one providing 18amps. combine them together and you have 36amps.
ps2: v7 scph-39001 - independence exploit - hdloader 0.8c - maxtor 300gb hdd
(+[__]%) psp slim ta-085v1: 6.60 PRO B10
wii (powered by bootmii/priiloader): 4.1u - d2x v10beta53-alt (base 56) - configurable usb loader v70r51/devolution r188 - wd scorpio black 7200rpm 320gig w/ ams venus ds2 enclosure
got a whole lot more to list . . .
This message has been edited since posting. Last time this message was edited on 10. November 2009 @ 00:06
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saxman2k
Junior Member
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10. November 2009 @ 13:33 |
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Thank you all for responding. When you say that I will need both connectors, do you mean the six pin? Could you link me to the adaptor that you are refering to?
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10. November 2009 @ 14:21 |
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Originally posted by saxman2k:
When you say that I will need both connectors, do you mean the six pin? Could you link me to the adaptor that you are referring to?
Go to the NewEgg page for your graphics card and click on the photographs of the card and its accessories. You will see a "Y" adapter that will connect two four-pin Molex 12-volt power plugs to one six-pin PCIE plug. The idea is to take one 12-volt power plug from each PSU rail and parallel them into one PCIE connector, thereby allowing the card to pull power from both rails.
This isn't an ideal solution, but it should work.
The ideal solution? I'm glad you asked. :) It is a single-rail PSU with its own six-pin PCIE power connector(s) with sufficient power for one connector to power your card without help from any other power sources.
If you do choose to use a two-source power connector, be sure you connect one four-pin power plug from each rail.
Dick
This message has been edited since posting. Last time this message was edited on 10. November 2009 @ 14:22
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saxman2k
Junior Member
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10. November 2009 @ 14:36 |
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I have been reading up on this, and there is a TON os speculation, but not alot of relivent information availible. The Y adapter you speak of makes sence, and now that I think on it I actually have the one that came with the card. I have heard however, that if your psu has 2 12+ volt rails with 18 amps a piece, AND a pci-e 6 pin plug built in, that the 6 pin plug will be supplied with enough amps for the card as long as the psu is capalbe of said amps overall. I have also read that the rails exist inside, and are nothing that can be identified on the wires. In other words, you cant pick which rail you are using, as there really is no telling. Egh.. Im not sure on any thing now, as EVERYONE has a contradicting opinion.
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saxman2k
Junior Member
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10. November 2009 @ 14:51 |
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And to pose another question, if you really can identify which rail you are using, then how does one go about doing so?
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saxman2k
Junior Member
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10. November 2009 @ 14:55 |
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Okay. Im triple posting now, but I just wanted to clarify. Simply put, if your PSU already has a 6 pin PCI-E plug on it, is it automaticly provided with enough amps from both rails to power your video card, or do you HAVE to use the provided adaptor to achive the proper amperage.
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10. November 2009 @ 15:25 |
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Originally posted by saxman2k:
I have heard however, that if your psu has 2 12+ volt rails with 18 amps a piece, AND a pci-e 6 pin plug built in, that the 6 pin plug will be supplied with enough amps for the card as long as the psu is capalbe of said amps overall.
Take nothing for granted and pay attention to what the PSU manufacturer says. Look at the side information panel on your PSU and it will tell you what is on each rail: 12V1 (12-vot rail #1) = M/B, PCI-E; 12V2 (12-volt rail #2) = CPU, Accessory. So your 6-pin PCIE connector is only connected to one 18-amp rail and all your 4-pin "accessory" connectors are connected to the other. You could probably jury-rig some Rube Goldberg combination of adapters to parallel your 6-pin and 4-pin connectors, but I repeat it would not be an ideal solution.
Originally posted by saxman2k:
I have also read that the rails exist inside, and are nothing that can be identified on the wires. In other words, you cant pick which rail you are using, as there really is no telling.
"Rails" is an engineering term to describe a common connection point. Rail, bus, bar and a half-dozen other terms are all similar. It may be implemented inside your PSU as a large copper wire, aluminum stock, or more likely just a common connection point. Again, look to the specs on the side of your PSU to determine what is on which rail.
Originally posted by saxman2k:
Egh.. Im not sure on any thing now, as EVERYONE has a contradicting opinion.
Please outline what is still confusing you. Perhaps someone else can explain it better than I.
Dick
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saxman2k
Junior Member
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10. November 2009 @ 16:54 |
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okay. Im pretty sure I got it, and again thank you. So I guess my final question is, if I were to plug this into my computer using the PCI-E pin on the PSU without any adapters, is it going to blow up my card under load?
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saxman2k
Junior Member
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10. November 2009 @ 17:39 |
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Also, I just read that the power consumption requiremnets stated for the cards are actually for the entire system, and if this is the case then I think I should be fine with my choice... I think...
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10. November 2009 @ 18:06 |
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Originally posted by saxman2k:
if I were to plug this into my computer using the PCI-E pin on the PSU without any adapters, is it going to blow up my card under load?
It could potentially do more damage to the PSU than to the graphics card. The PSU could be exposed to excessive current draw leading to that wonderful aroma of over-heated components, while the card would likely be exposed to less than 12 volts which would only affect its performance. Of course, if the PSU self-destructs there is no telling what kind of spike it might send down the rails in the process.
Also, don't forget that the PCI-E connector shares the 18-amp 12-volt rail with the motherboard. It would be interesting to research how much current your motherboard needs.
Originally posted by saxman2k:
I just read that the power consumption requiremnets stated for the cards are actually for the entire system.
The recommended wattage of the PSU (450 watts) is the minimum for the system. I'm pretty sure the 26 amp requirement (which is only 312 watts) is just for the graphics card.
You might want to contact EVGA Tech Support and simply ask them if 18 amps is sufficient to power the card. They know their product better than I do.
Dick
This message has been edited since posting. Last time this message was edited on 10. November 2009 @ 18:08
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saxman2k
Junior Member
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10. November 2009 @ 18:19 |
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Will do. And thank you. You have been very helpful. :)
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11. November 2009 @ 19:17 |
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Originally posted by mike.m:
The PSU has 1 6-pin connectors, and GPU says 2 x 6 Pin. I would imagine that you only need 1 x 6 pin connector, and that the other one is a backup
Hi, Mike.
Power conductors like wires, plugs and connectors are all current-limited. If you put too much current through a given conductor they will overheat--sometimes quite dramatically. When you reach the current limits of a given conductor, you can simply add another one in parallel to double their combined current handling capability.
This card has two 6-pin connectors because it requires two 6-pin plugs and cables from the PSU to supply the required current load. Bigger nastier cards even require three plugs or combinations of multiple 6- and 8-pin plugs simply because they require even more current. For example, an EVGA GTX 285 card calls for both 6- and 8-pin connectors to handle the 46 amps it needs.
When cee43ja1 said that "both power connectors" will be needed I misinterpreted what he meant. I apologize. He was correct in that both of the two 6-pin PCI-E power connectors will be needed to handle the current requirements of this card. This PSU only has one.
He was also correct when he said if saxman2k can return the PSU he probably should do so and get a properly rated Corsair PSU. If he bought the PSU from Newegg he has 30 days to return it for a refund. He will have to eat the shipping back and forth in addition to a 15% restocking fee, but the cost of learning is often expensive.
I have a current build with two EVGA 9800 GTX and my PSU provides four 6-pin+2 PCI-E plugs: two for each of the 9800s. The PSU is a single-rail 52-amp (12 volt) supply and it is fully maxed out with the two 26-amp 9800s.
I have another build with two EVGA GTX 260 and that PSU provides six 6-pin+2 PCI-E plugs: two for each of the 260s and two in case I decide to add a third for TRISLI. The PSU is a single-rail 78-amp (12-volt) supply and the pair of 260s combine to draw 72 amps, so for this build that third pair of PCI-E connectors will never get used.
So that second PCI-E connector isn't a backup. Both connectors are needed to supply all of the current this card requires.
Dick
This message has been edited since posting. Last time this message was edited on 11. November 2009 @ 19:18
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saxman2k
Junior Member
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11. November 2009 @ 19:26 |
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Dick,
My card is the 9800GTX+ Superclock edition, which only has one 6 pin power input.
Justin
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11. November 2009 @ 20:37 |
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Originally posted by saxman2k:
My card is the 9800GTX+ Superclock edition, which only has one 6 pin power input.
Hi, Justin.
Well, I bow to reality which trumps documentation every time. EVGA's product sheet calls for 24 amps, but doesn't specify how many connectors. EVGA's support FAQ calls for 26 amps and two connectors. NewEgg's product specifications call for two connectors. And it wouldn't surprise me if the package your card came in specifies an even different requirement. What you are holding in your hand is the ultimate authority as to the number of connectors the card requires. No more arguments from me.
As for the bouncing current requirements, I just noticed an interesting notation on EVGA's product page for your card. While calling for a 24 amp minimum 12-volt supply, it goes on to say that if you are going to run SLI (with two cards) the minimum only goes up to 30 amps! That makes no sense to me at all, unless SLI operation imposes its own independent power requirement. I give up.
I stand behind my comments regarding PSUs in general, but EVGA's inconsistent specs leave me totally confused. My (last) suggestion would be to just plug your card into your PSU and keep an eye on the PSU temp for awhile. If the card doesn't seem happy, measure the PSU output voltage with the card under load to see if the PSU is able to maintain a solid 12 volts. Please report back here to let us know how it all works. I feel like an expectant father. :)
Best of luck! (and I'll be quiet now)
Dick
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saxman2k
Junior Member
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11. November 2009 @ 20:49 |
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:) I actually installed it last night, and played the new batman game on highest settings with maxed out physics for 3+ hours with my q8200 OC'ed to 2.9GHZ. Everything ran perfect, and whenever I got up to feel the PSU, it was completely cool as though it was just at idle. Do you have a program you can reccomend to monitor the voltage? I tried speed fan, but at idle it says my +12 Volt rail is putting out about 1.3 volts, which cant be correct.
That is strange about the meger 6 amp increase in demand for SLI. I here tell that alot of the times graphics card companys over exadurate the requirments to stay on the safe side. All things considered, im thinking that im safe, although I would like a definate answere, it would seem that only time will provide me with one. That being said, if you can reccomend a better program to monitor the power consumption, I would be more that happy to post my findings asap.
Justin
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AfterDawn Addict
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11. November 2009 @ 21:07 |
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the power requirement is for one card in a COMPLETE system, not the card itself.
imagine having 3way sli/quad crossfire. if each card required 500-600watts, that would mean a 2kilowatt power supply would be needed. and there is no such thing.
all you need is a trustworthy brand that delivers clean and stable power. corsair, seasonic, pc power&cooling are highly recommended.
ps2: v7 scph-39001 - independence exploit - hdloader 0.8c - maxtor 300gb hdd
(+[__]%) psp slim ta-085v1: 6.60 PRO B10
wii (powered by bootmii/priiloader): 4.1u - d2x v10beta53-alt (base 56) - configurable usb loader v70r51/devolution r188 - wd scorpio black 7200rpm 320gig w/ ams venus ds2 enclosure
got a whole lot more to list . . .
This message has been edited since posting. Last time this message was edited on 11. November 2009 @ 21:08
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saxman2k
Junior Member
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11. November 2009 @ 21:19 |
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cee43ja1, I noticed OCZ was not on your list. Do they not make a good PSU?
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11. November 2009 @ 21:37 |
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Originally posted by cee43ja1:
the power requirement is for one card in a COMPLETE system, not the card itself.
Thanks for the voice of experience. I've obviously been over-estimating them. How can one determine the power requirements for individual cards?
Dick
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saxman2k
Junior Member
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11. November 2009 @ 21:47 |
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Dick,
I have personally have seen lists online of what people say are the power requirements of individual cards, but nothing official.
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11. November 2009 @ 22:29 |
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Thanks, Justin.
I have posed this question to EVGA Tech Support and I will report back what they say.
By the way, if you can point me to one of those lists that happens to cover EVGA/Nvidia cards, would like to take a look.
Thanks.
Dick
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saxman2k
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11. November 2009 @ 23:37 |
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12. November 2009 @ 00:19 |
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Thanks.
The article was interesting (though not terribly kind to "cheap" PSUs that only provide 17A on the 12-volt rail ::smile:: ) and I've saved the load table. Some of the comments, however, were really unbelievable. According to some of the commenters if you only load a 500 watt PSU with 400 watts, then you are really stupid because the PSU is burning off those other 100 watts all by itself. I suppose if you unplugged everything from the PSU then it would consume the entire 500 watts by itself. Unbelievable.
Thanks, again, for the reference, Justin. The load table itself looks quite reasonable as does the testing methodology.
Dick
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