Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: Tyrian on November 18, 2011, 11:11:15 am
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I suppose this is technically a simple question, but it's giving me trouble because the power specs I'm finding aren't consistent with each other.
My question is this: I currently have a Corsair HX1000 PSU and an EVGA GTX 285 GPU. I'm looking at getting a GTX 570. Is it possible for me to run an EVGA GTX 570 as my GPU, while keeping my GTX 285 card for Physx?
Simple, right? Here's where things get irritating. The HX1000 is a 1000W PSU, with two 12V rails, each capable of delivering 40A. However, the construction of the PSU is actually two 750W units working in concert. I've looked at the official spec sheet from EVGA, posted here (http://www.evga.com/products/pdf/012-P3-1570.pdf), and it lists its PSU requirements as 550W, with a minimum of 38A on the 12V rail. However, if you look on the Newegg page here (http://www.newegg.com/Product/Product.aspx?Item=N82E16814130593), it lists the minimum PSU wattage as 550W, with the max power draw being 219W. But if you calculate the current from the max power draw, it comes out to 18.25A, which is odd because EVGA's page lists current requirements as 38A. But since the GTX 570 has two 6 pin power connectors, is that 18.25A per input connector or the sum of the input connectors? It makes some sense if it's per connector because then the total current draw is then 36.5A, which is pretty close to the 38A in the official spec sheet. As for my EVGA GTX 285, it's listed as needing a 550W PSU and its max power draw is listed as 204W, referenced from NVIDIA's site here (http://www.nvidia.com/object/product_geforce_gtx_285_us.html). I seem to recall the current requirement for the 12V rail was 40A, and that's corroborated by this post on Tom's Hardware here (http://www.tomshardware.com/forum/259345-33-4x18amp-rails-amps-recommended-good). But again, based on the max power draw, the needed current is 17A, with the same confusion as above. I've also done some additional research on the GTX 570 and have seen some people claiming that they're running three GTX 570s in SLI with the HX1000. Lastly, I've run a PSU calculator and it says that for everything in my system, 570 included, it says I only need a 780W supply, but there's no info on current draw.
So, bottom line, can an HX1000 power a GTX 570 and GTX 285, along with all the rest of the stuff in my system? Or would it be better to wait for the new Kepler cards in early 2012, as they're supposed to offer decreased power needs? My remaining parts are an EVGA E760 motherboard, two WD hard drives, a DVD drive, an Intel Core-i7 920, and 6GB of RAM. I'm not currently overclocking anything, but I may in the future. (Although it's far enough in the future that I'll probably snag a new PSU for that.)
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http://psucalc.net/download.php
EDIT: FYI, your CPU is a Bloomfield i7
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I would always take the card manufacturer's word on the technical requirements of a piece of hardware over 3rd parties, as they generally subject them to a broad variety of tests in order to determine them (with a safe margin built in).
With a PSU rated for 1000W, I'd suggest you simply try both and watch for system instability. Intermittent power issues are notoriously finicky, so instability is a fair bet if the PSU isn't delivering quite enough.
Before you wait on the promise of newer hardware, keep in mind the price-performance curve; the newer it is and the more you spend on it only is worth it to a point. It's why mid-range hardware is universally a better bang-for-buck than top-tier.
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I might take a look at that PSU calculator. I used the one here (http://extreme.outervision.com/psucalculatorlite.jsp). I'm currently trusting the manufacturer's specs right now. Somewhere I read that the specs on the EVGA sheets were for approximate total system load, not for the card itself. I'm going to see if I can't validate that claim. The reason that I was wondering if I should wait for Kepler has more to do with it potentially driving down the price of the 500 series cards, although lower power consumption would be nice.
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i'm sure it will be fine so long as you keep the vid card on one rail and everything else on the other.
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http://psucalc.net/download.php
EDIT: FYI, your CPU is a Bloomfield i7
Seconded, as that calc takes overhead, ram, hdds, fans, mild overclock, etc, into consideration and then gives you a list of PSUs proven to be up to the task.
Bloomfeild i7 + 570 + PhysX 285 + Generic Assumption (4 ram sticks, 2 hdds, 1 optical, 5 case fans):
(http://img843.imageshack.us/img843/8464/68215540.png)
Call me crazy, but I have a feeling your 1000w might be just a tad overkill. If you have questions for the guys who made the calc, you can ask them here (http://www.overclock.net/t/1140534/psu-calc-final-release).
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@Klaustrophobia: That's what I was thinking. I was going to put the 285 and 570 on the same rail, and everything else on the other one. If that doesn't work, I'll move the 285 to the other rail.
@KyadCK: The 1000W PSU was supposed to be overkill. When I built my system, I knew that I wouldn't have all the add-in cards I wanted. I didn't want to have to upgrade my PSU with every other upgrade, so I went a little overboard intentionally.
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@KyadCK: The 1000W PSU was supposed to be overkill. When I built my system, I knew that I wouldn't have all the add-in cards I wanted. I didn't want to have to upgrade my PSU with every other upgrade, so I went a little overboard intentionally.
To give you an idea of just how much overkill, you can run three 590s without breaking the 1000w mark. Atleast you can be happy that the PSU will last you for several builds and handle anything you can possibly throw at it, which is a good feeling indeed.
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In terms of wattage, maybe. But that's only half the battle. You also have to make sure you can push the needed current safely. That's why I'm having difficulty reconciling the different listed current specs. I may call EVGA and ask their tech people about it.