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Is my PSU strong enough for this Graphics Card? (and a few other PSU-related questions)

Davcoll

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Jun 28, 2014
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I have a few questions about my build and about the Power Supply. Keep in mind that I'm new to building computers.

Build - http://pcpartpicker.com/p/GZHnBm

Questions:

1: The title of this thread.

2:Can I even install the GPU? I heard somewhere that the GTX 980 TI uses 6x8 pin connectors and according to pcpartpicker my PSU only has 4 6x2 connectors or something along the lines of that. Can I still install the GPU?

3: What is considered a safe/good/whatever leftover wattage? For example: if my computer is using up 300W and it's running a 400W Power Supply, is that ok? Is there a standard to how much wattage leftover that is considered to be good? I know when overclocking you sometimes need to increase the voltage, would that mean upgrading?

4:If I ever needed to SLI two of these in the future, let's say for 4K, would I need to upgrade my PSU?

5: I might OC my CPU/GPU. Should I possibly consider a new PSU or will this one suffice?

Any response is taken into consideration.
 
Solution
1. Your PSU should be fine.
2. Some GTX 980 TI's have two 6-pin PCI-E power connectors, some have one 6-pin and one 8-pin. Either way you should be fine. Your PSU likely has 4 PCI-E power connectors that are 6 or 8 pin. Usually 2 extra pins on the side are detachable so it can work with either. Doesn't really matter, if you only have 6-pin connectors you can get an adapter to turn two 6-pin connections into an 8-pin connection and then it will still work, but like I said I'm fairly sure it has the proper connections already.
3. Usually you want to be sitting around 80% load of your PSU or lower. Probably somewhere around 550-600 W for a 750 W PSU. your PSU probably falls about right for that.
4. If you went for SLI (which I personally...
1. Your PSU should be fine.
2. Some GTX 980 TI's have two 6-pin PCI-E power connectors, some have one 6-pin and one 8-pin. Either way you should be fine. Your PSU likely has 4 PCI-E power connectors that are 6 or 8 pin. Usually 2 extra pins on the side are detachable so it can work with either. Doesn't really matter, if you only have 6-pin connectors you can get an adapter to turn two 6-pin connections into an 8-pin connection and then it will still work, but like I said I'm fairly sure it has the proper connections already.
3. Usually you want to be sitting around 80% load of your PSU or lower. Probably somewhere around 550-600 W for a 750 W PSU. your PSU probably falls about right for that.
4. If you went for SLI (which I personally never recommend for countless reasons) you probably would need a better PSU. I think about 850 W is probably the safe area for doing SLI with these cards. You might go ahead and get an 850 W PSU to avoid this issue down the road.
5. OC on this PSU shouldn't be an issue.
 
Solution
Here is Guru3D's power supply recommendation:
•GeForce GTX 980 Ti - On your average system the card requires you to have a 600 Watts power supply unit.
•GeForce GTX 980 Ti SLI - On your average system the cards require you to have a 900 Watts power supply unit as minimum.

If you are going to overclock your GPU or processor, then we do recommend you purchase something with some more stamina.

That's directly from the Guru3D review of the 980 TI. If you plan on overclocking the card, especially if you're also overclocking the CPU, I'd want at least a really good 650w unit, but you could probably get by with the minimum recommendation if you had to. It might run the PSU fan a bit louder and might not be quite as efficient or cool though. Considering that graphics cards occasionally peak outside the specifications, I like to have a little more room for error.


 
1. Yes

2. Yes, you can install the GPU. If pcpartpicker says there's no compatibility errors, then there's no compatibility errors. If it's unsure, it'll display a message.

3. If you have say, 1000W on a 250W build, it would still be fine, just a waste of electricity. You should have a power supply that has 100+W of what you'll actually need, 50W if you aren't overclocking.

4. If you want to SLI your 980 Ti's sometime, then get an 850W power supply. Otherwise 750W is more than enough for one 980 TI.

5. The 750W is more than enough for your CPU/GPU/Overclocking. 850W is just perfect for your CPU/2 GPU's/Overclocking.




 
3. If you have say, 1000W on a 250W build, it would still be fine, just a waste of electricity. You should have a power supply that has 100+W of what you'll actually need, 50W if you aren't overclocking.


This is absolutely wrong. The system will only pull what it needs, and the PSU will only supply what the system demands. If the unit is a good one, regardless of how much larger than necessary the unit is, it will only run cooler and more efficiently. It will also probably last much longer as it will never be run anywhere near it's ability to sustain the demand or continuously be run under "hot" conditions. It will also run quieter as the fan won't be likely to be running at max speeds anytime it's under a load.


http://www.jonnyguru.com/modules.php?name=NDFAQs&op=FAQ_Question&ndfaq_id=3


Having a 1000w unit in use with a system that only uses 500w does not "waste" 500w, or any other amount simply due to the nature of it being a larger capacity unit. The only waste in regard to a PSU, is with a model with a low efficiency rating, which by the way does not guarantee a quality unit simply due to having a high efficiency rating, that sheds more of it's generated power as heat rather than as actual consumed power to the system.
 


Well, that's nice to know. I thought the PSU would generate 1000W and then give the computer only what it needed.
 
Nope, not at all. The efficiency does go up and down through power levels though. It isn't a big deal, but I usually try to gear PSUs to land in that more efficient range when the system is powering the max amount of power. That is also partially because I don't want to push the PSU too hard at close to 100% load itself, but really there isn't any major issue even if the PSU is wildly over powered.
 
The power supply doesn't "generate" anything. In it's simplest terms, it converts AC power to DC power in the amounts required by the hardware using it according to demand. If the graphics card needs 175w, that's what it uses. If a fan needs 2w, that's what it pulls through the PSU. The act of converting the power from AC to DC does use some additional power that's wasted and this is where the efficiency of the unit comes into play. Less efficient units waste more power during conversion and supply of power to the hardware, but it has little to nothing to do with the maximum capacity of the unit being more than what your system actually uses.

http://www.tomshardware.com/forum/343495-28-power-supply-efficiency-myths