6670 on 300w?
- Thread starter nj473
- Start date
MyCattMaxx
Active Member
Don't forget that the wattage on the +12 volt rail is the important part.
You can have a 600 watt PS but only have 240 watts of it on the +12 volt rail.
Like bigfella said, look at the +12 volt amp rating.
You take the +12 volt amp rating and multiply it by 12 to figure out the wattage on that rail.
You can have a 600 watt PS but only have 240 watts of it on the +12 volt rail.
Like bigfella said, look at the +12 volt amp rating.
You take the +12 volt amp rating and multiply it by 12 to figure out the wattage on that rail.
Forgot to include the card reader component, new result:
Minimum: 203w
Recommended: 253w
How accurate is this result? Because doesn't it mean that theoretically it would work?
Anyway I will check the PSU itself tomorrow and find out all details I can, I'm not 100% on the +12 volt amp stuff though so I will try and make as much sense of it as possible.
Yeah I saw the 400w rating but I always thought that was just cover as the card isnt using the whole 400w. Thats what got me thinking in the first place, as the 6670 apparently uses 60something watts and the 5570 only 42. I don't really know roughly how much each other component uses on average i.e. HDD's, RAM sticks, fans etc so its difficult to say exactly how much is being used isnt it...
Come to think of it is there any physical way available to test exactly how many watts your computer is using?
EDIT: in response to Russ88765's post I don't think there are any plans to overclock if that helps
Minimum: 203w
Recommended: 253w
How accurate is this result? Because doesn't it mean that theoretically it would work?
Anyway I will check the PSU itself tomorrow and find out all details I can, I'm not 100% on the +12 volt amp stuff though so I will try and make as much sense of it as possible.
Yeah I saw the 400w rating but I always thought that was just cover as the card isnt using the whole 400w. Thats what got me thinking in the first place, as the 6670 apparently uses 60something watts and the 5570 only 42. I don't really know roughly how much each other component uses on average i.e. HDD's, RAM sticks, fans etc so its difficult to say exactly how much is being used isnt it...
Come to think of it is there any physical way available to test exactly how many watts your computer is using?
EDIT: in response to Russ88765's post I don't think there are any plans to overclock if that helps
MyCattMaxx
Active Member
Here is an example of a "so called" 450 watt max PS that I replaced for a guy who's computer kept crashing after he put in a new vid card.
He said over the phone that his PS was big enough, but after I showed him and put in a new PS his problems went away.
He said over the phone that his PS was big enough, but after I showed him and put in a new PS his problems went away.
To account for weak PSU like his and give you head room if you're running a lot of other power intesnive hardware. You should really upgrade to a better PSU. The Corsair CX430 would be an excellent choice. You don't want to risk any complications or take out your whole system. A better PSU will also allow for other upgrades later if you want.
Thanks for that pic of the PSU, I didn't know it was that complex to be honest I thought 300w meant 300w all round.
I think it's clear now that it is just best to upgrade the PSU if I am going to upgrade the graphics, I suppose it's just the thing of not wanting to spend extra money but oh well better safe than sorry, and yeah at least it makes things simpler to upgrade in the future!
Cheers
I think it's clear now that it is just best to upgrade the PSU if I am going to upgrade the graphics, I suppose it's just the thing of not wanting to spend extra money but oh well better safe than sorry, and yeah at least it makes things simpler to upgrade in the future!
Cheers
MyCattMaxx
Active Member
Yup, My 550 watt PS has 38 amps (456 watts) on the +12v rail, so I have plenty of room for the GTX 460 that I ordered this morning.
Russ88765
Active Member
What about after everything else is added on top of the gpu?
MyCattMaxx
Active Member
My vid card is rated at 160 watts under full load.
My cpu is 95 watts, so that is 255 watts there.
I doubt my extras pull 50 watts, but for arguments sake we will factor that value.
Total at max load is 305 watts so I have 151 watts of headroom on the 12v rail.
Okedokey
Well-Known Member
There seems to be a lot of confusion here about PSUs, so just to clear things up.
1. Different ATX standards will isolate 12V_1 or 2 for the CPU only. This essentially renders any additional amperage on that rail unusable by the rest of the 12V system including the GPU. So look at the design standard, if it doesn't have EPS, then you should assume unless stated otherwise, that the 12V_1 is not part of the equation.
2. Another way to look at the above is to divide the total wattage on the 12V rail by 12. This will give you the number of available amps. It needs to be 26 or greater for any PCIe card.
3. Calculators are crap. They dont factor in capacitor ageing, derating curves etc and give a super unrealistic outcome. Also component TDPs mean little in the real world, especiallly if you overclock or similar.
4. Once you have your 12V amperage figure, deduct 0.1 - 0.3 amps for every degree (C) that it will operate under during summer. Most cheaper PSUs are rated at 25oC, so during summer, inside your computer (with other heatloads), it could easily be 50oC. That is delta 25oC. So that means that you need to deduct up to 8.25A off the 12V rail due to derating (temp). So now that cheap 500W PSU that had 15A on the 12V rail can only in reality provide less than 10A. (8.25A/2 = 4.125A per rail deducted + capacitor ageing (below)).
5. Add to the above losses - capacitor ageing. Remove a further 15% for capacitor ageing.
6. So what you're left with is a PSU that during summer in a year from now may only be able to provide 5A (60W) to the GPU once you remove the CPU rail.
Of course higher quality single rail PSUs with active PFC, MTFB measured at 40oC, japanese capacitors etc, will only derate by a few amps, and given a single rail design, a high quality 500W PSU can deliver 40A or more, vs a cheap brand 500W PSU delivering 10A.
Extreme cases of course, but shows the lack of information wattage rating tells you.
You need 26A on the 12V rail, but I would recommend 30A as this is achievable in the corsair 400 - 500W range for not much money.
1. Different ATX standards will isolate 12V_1 or 2 for the CPU only. This essentially renders any additional amperage on that rail unusable by the rest of the 12V system including the GPU. So look at the design standard, if it doesn't have EPS, then you should assume unless stated otherwise, that the 12V_1 is not part of the equation.
2. Another way to look at the above is to divide the total wattage on the 12V rail by 12. This will give you the number of available amps. It needs to be 26 or greater for any PCIe card.
3. Calculators are crap. They dont factor in capacitor ageing, derating curves etc and give a super unrealistic outcome. Also component TDPs mean little in the real world, especiallly if you overclock or similar.
4. Once you have your 12V amperage figure, deduct 0.1 - 0.3 amps for every degree (C) that it will operate under during summer. Most cheaper PSUs are rated at 25oC, so during summer, inside your computer (with other heatloads), it could easily be 50oC. That is delta 25oC. So that means that you need to deduct up to 8.25A off the 12V rail due to derating (temp). So now that cheap 500W PSU that had 15A on the 12V rail can only in reality provide less than 10A. (8.25A/2 = 4.125A per rail deducted + capacitor ageing (below)).
5. Add to the above losses - capacitor ageing. Remove a further 15% for capacitor ageing.
6. So what you're left with is a PSU that during summer in a year from now may only be able to provide 5A (60W) to the GPU once you remove the CPU rail.
Of course higher quality single rail PSUs with active PFC, MTFB measured at 40oC, japanese capacitors etc, will only derate by a few amps, and given a single rail design, a high quality 500W PSU can deliver 40A or more, vs a cheap brand 500W PSU delivering 10A.
Extreme cases of course, but shows the lack of information wattage rating tells you.
You need 26A on the 12V rail, but I would recommend 30A as this is achievable in the corsair 400 - 500W range for not much money.
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