what ups i need for 750w psu ?

[masterhelper]

please help me to choose good ups for my computer and how to know VA i need ?
power supply :
XFX Core Edition Pro750W

other component

Intel® Core™ i7-3770K Processor 4.6Ghz 1.24v
GIGABYTE GA-Z77X-UD5H Wifi EDITION LGA 1155
CORSAIR XMS3 16GB (4 x 4GB) 1600
GB WINDFORCE GTX 670 OC 2GB
LG Cinema 3D Monitor D2342P 23" FULL HD LED 1920X1080
h.D WD green 500 gb
Kingston HyperX 3K 120GB SSD 6Gb/s
Cooler Master's HAF XM With 4X 200MM
Antec Kuhler H2O 620 Cpu Cooling System

plus 3 fans in the case

 

[masterhelper]

please efficient and cheap ups

 

[larrymoencurly]

I'm going to say 1500 VA to handle the worst case. My assumptions:

80% efficiency, meaning 750W output requires 938W input.

95% power factor, which is realistic for PSUs with automatic power factor correction (actually many do 99%). VA = watts / (power factor), or in this case 987 VA. However, you can't buy a back up rated 987 VA that has a power rating of 938W, and typically the watt rating is only about 60% of the VA rating. 938W / (60%) = 1563 VA.

 

[NiHaoMike]

Find a used rackmount unit for cheap or free, then replace the batteries. The rest of the unit rarely fails.

 

[masterhelper]

I'm going to say 1500 VA to handle the worst case. My assumptions:

80% efficiency, meaning 750W output requires 938W input.

95% power factor, which is realistic for PSUs with automatic power factor correction (actually many do 99%). VA = watts / (power factor), or in this case 987 VA. However, you can't buy a back up rated 987 VA that has a power rating of 938W, and typically the watt rating is only about 60% of the VA rating. 938W / (60%) = 1563 VA.

omg 1500 vA too too expensive lol cannot buy ups with this va

 

[masterhelper]

Find a used rackmount unit for cheap or free, then replace the batteries. The rest of the unit rarely fails.

pls step by step i dont know how to do that ,sorry please suggest good ups brand

 

[masterhelper]

for my pc can i got ups less than 1500 VA with good brand just to manage the electric in my pc ?

 

[Conumdrum]

You need 1500 VA. My 1000 w PSU under load has shut my UPS DOWN and I have a 1500 VA Ups.

 

[Bobnova]

That computer is worth maybe 330w from the wall at full load. Add in the monitor if you want and it's still less than 400w. PSU size != PSU draw.
Given 400w and the average of 0.97-0.99 for good, modern, PSU power factor, and you need 450VA. Call it 500 in case the monitor PF is really, really, really horrible.
So, 450w and 500VA, more than that and you should be good.

EDIT:
If you have a 1500VA UPS that is rated for 1000w and your rig shut it down, either it isn't what it says it is or you are drawing vastly more power than you should be.


Now, that said, as with pretty much everything you can look at the list of three features below, and pick two:

1) Low price.
2) High Quality.
3) High Performance.

 

[Conumdrum]

Agreed Bob. He doesn't need that for his system with the lower wattage his unit pulls. Your correct about what he needs.

But he does have a 750 watt PSU. So just looking ahead.

My issue is this. I overclocked my 470s and ran the new Furmark max settings and P95 to stress my system to max. I was pulling 900+ watts on my UPS and it started beeping and finally just shut down, it reset just fine. It's a 1500 VA Cyberpower Truesine? My PSU is a Ultra x3 1000 that isn't the most efficient. I don't have the PC connected to my PSU, just never had a need. Maybe I should to monitor it more eh?

Thanks Bob, good input as usual.

 

[Boulard83]

I run a 1500VA/900w on main rig and a 1350VA/810w on the HTPC. Both run great and i never had issue. Had a much more power ungry computer in the past and both UPS never failed on the "big rig".

 

[masterhelper]

thanks alot guys

 

[NiHaoMike]

Also beware that a small UPS might not survive the inrush from a large PSU even if it's loaded lightly. I once had a cheap 425VA Energizer UPS blow its MOSFETs when I plugged a 430W Antec PSU into it, before I even turned the PC on.

pls step by step i dont know how to do that ,sorry please suggest good ups brand

Pretty much any rackmount UPS you'll find is going to be good quality. (After all, their main use is in server rooms.) APC is a very well known and good brand, but Eaton, Tripp-Lite, and Liebert are some other great brands.

As for replacing the batteries, it's very easy to do on any good UPS and the manufacturer will provide directions. Note that on the UPSes that have multiple batteries in a pack, it's often cheaper to open the pack and replace the actual batteries inside instead of buying a new pack. On every small UPS (1500VA or less) I have seen, the batteries are connected with quick disconnect tabs and are very easy to replace.

 

[KillemTheGecko]

Also beware that a small UPS might not survive the inrush from a large PSU even if it's loaded lightly. I once had a cheap 425VA Energizer UPS blow its MOSFETs when I plugged a 430W Antec PSU into it, before I even turned the PC on.

Pretty much any rackmount UPS you'll find is going to be good quality. (After all, their main use is in server rooms.) APC is a very well known and good brand, but Eaton, Tripp-Lite, and Liebert are some other great brands.

As for replacing the batteries, it's very easy to do on any good UPS and the manufacturer will provide directions. Note that on the UPSes that have multiple batteries in a pack, it's often cheaper to open the pack and replace the actual batteries inside instead of buying a new pack. On every small UPS (1500VA or less) I have seen, the batteries are connected with quick disconnect tabs and are very easy to replace.

+1 on this. It is very easy to replace most UPS batteries.