I've got a Be Quiet! Dark Power Pro 650W PSU, a nice stable modular unit, with 4 12V rails supplying 20A each. I've also got a 9800 GTX+, which is still okay, but I wanted a little more memory for Wings of prey so I could run it on a higher texture setting, it was fine otherwise. I got a Palit GTX 460 1Gb, but I've found this cuts out all the time, and it seems it's because it needs 24A across it's 2 x PCIe power connectors, but my PSU can only supply 20A per rail and both PCIe connectors come off the same 12V rail. 1. Is 24A unusually high for a modern mid range DX11 graphics card, or is my PSU out of touch with the current range of cards out there? 2. Any ideas on how to rig up my PSU to provide more than 20A? The only thing I can think of is using 2 spare Molex connectors via an adaptor to make an alternative PCIe power connector that comes off a different 12V rail, but there's a few comments around that this can be dodgy. Anybody? 3. Maybe I should just get an MSI R6850 Cyclone - May's buyers guide raves about it, it's cheaper than an old GTX 460, and the review at least says it uses 1 x 6 pin OCIe power connector, os presumably the power drawer is lower? Thanks Jeff.
Somethings up. You could run a 460 GTX on a 400watt PSU. in fact many people do. Did you run furmark or anything?
You should be able to use 2 different rails without an issue. Just plug the modular cables that came with your PSU into the slots on the PSU. Make sure that you plug them into the correct one however. They do mark them so it shouldn't be too hard. Use one hard wired PCI-E 6-pin and one modular PCI-E 6 Pin.
Thanks for the replies: I know it's nothing to do with DX11, I just mean recent mid range cards - what is a 'typical' current draw? My PSU can output no more than 20A per rail - am I screwed in terms of meaningful upgrades from my 9800GTX+? The P7 darkpower 650 has no captive cables, and both PCIe connectors are on the same rail. There are no spare rails, the other three are ATX and EPS, both on my P5K mb, and the last is Molex etc, so my only chance for more than 20A is using that - bit dodgy? Don't want the hdd packing up either! Jeff
Isn't 288W for a mid range card fairly high?? I thought that kind of poewer draw was 480's range... Where did you get this 24A from?
288w for a mid-range card is way out. You sir, either have a faulty card or need to check the source of your current measurement.
In fact a 9800GTX+ draws more power (about 9w) than a 460, have you got it plugged in properly, with both connectors coming from a different rail? You also have to take into account that up to 75W (6.25A) comes from the same rail that the MB is powered by, some cards require more than others but 20A should be more than enough for one card. If you connect up molex connectors to a graphics card slot then you have to be aware that this is most likely to be coming from the same rail that powers your MB, and all your drives so it might end up being a bit much. Another consideration for molex adapters is the wire itself, if possible it's best to put each molex connector onto a different wire from the PSU to avoid one wire overheating if it's too thin, some are 18AWG which is thinner than 16AWG (American Wire Gauge). When I had much more limited choices in power connections (2 rails instead of 4) I found that one of my 9800GTX+ (the closest to the front) drew much less power than the other one, you may find the same with your 460 as they have access nearly an extra 75W that they will never need, so it's worth trying any combination to see what works. Another tip is to play with Vsync enabled (and triple buffering to smooth out framerates) as this limits the amount of frames the gfx card needs to draw, and therefore the amount of power needed to do so. I've had HD's that will only work if I plug them in on separate molex cables, not sure why but I had to be careful about how I plugged things in even to get my old system to boot up. Technically your 460 should need no more than 13A on the 12v rail to power it so one 20A 12v rail should handle it. First I'd try swapping cables round to see what works or not. By the cards design, each connector, including the slot should be on a different circuit to accommodate for PSU's that have truly have several 12v rails (instead of what most have which is one rail divided by limiters into several) otherwise the difference in power fluctuations would potentially damage the cards. Failing all this have you got access to a different PSU to try it with? Even the best makes/models of PSU have duffs every now and then.
I have a BQ DPP 650w. More than enough, my 4870x2 is still one of the biggest power munchers out there and runs very happily on my DPP. Something else is afoot.
Palit tech support have confirmed to me that the GTX 460 Sonic 1Gb require 2 x PCIe 12V supplying 24A, and yeah, it sounds a lot. What I'm trying to figure out is if 24A is unusual for a modern mid range graphics card and I'm just unlucky, or whether my PSU is doomed to obsolesence if it can only supply 20A to both PCI connectors.
narwen... where are you getting you're information...it is inaccurate, so look elsewhere op... i can't take the time to look at your unit, but if the 2 pci-e outputs are on the same rail, which would be odd, then you will need to find a way to get on another rail. two molex to pci-e will work, although it can be a bit dodgy, as someone said earlier they don't do the best job carrying the power, but it should suffice. most reviews i see say a gtx 460 needs 24 amps. the sonic probably requires more, although only slightly... one other note, i know back in the day alot of psu makers were claiming multi-rail setups, but in reality the were single rails modified... i believe topower is the oem for the bequiet series, so there's that bit of info as well...
Your psu supplys 52A over the 12v rails, so yes you can handle a 460. In fact you should be able to handle almost any single gpu on that.
trig before you some one is wrong get your facts right first the maxium a gpu with 2 pcie 6pin can draw is 225w = 19.75a. spec for 460 says 160w = 13.3a every review i've seen say about 288w = 24a for the hole pc not just the gpu Because the 1 GB card is rated for up to 160 W, while the 768 MB board has a 150 W thermal design power spec, they employ the same twin 6-pin PCI Express power connectors. http://www.tomshardware.com/reviews/geforce-gtx-460-gf104-fermi,2684-2.html
sorry, but ur wrong again... first i'll hit what may be a typo, 225/12 does not equal 19.75...it's 18.75... additionally...the 225 is including the 75 it can get from the pci-e slot, so technically it can only draw 75 per pci-e cable from the psu, so it can't draw 19.75 or 18.75 from the two 6 pin pci-e connectors... finally, i know that the gpu itself does not require more than 20 amps, and that the figure of 24 amps is for the whole system ('typical'), but i don't have time to post a 1000 word document everytime someone asks for amp requirements on a gpu, so i go with the standard...and it works, because without having any idea what his rig has in it, it's a safe bet that he is pulling more than 4-6 amps off of the same rail his gpu is pulling from so, if you go by what the maximum tdp of the card is, then you get 160/12, which is not 16 amps, it's 13.3...which you got right in your second post...congratulations... additionally, the 580 has a tdp from what i read of almost 250, making it around 20-21 amps...which last i checked isn't under 20 so, i apologize that you didn't get your facts totally straight before your posts...try to do a little better next time... as i said before, op will want to use a different rail, with molex to 6-pin converters, and preferably from two different molex cables...
