Looking to SLI, PSU question

[Wrestler10307]

Hey guys, I'm looking at possibly adding another MSI 660 ti to my rig, but I'm not sure if my PSU can handle it... build is in sig and also below.

Intel i5-3570k @ 4.0ghz
ASRock Extreme4 Z77
16gb G.Skill 1866
MSI 660 ti PE/OC
2 SSD, 2 7200 HDD
BD/R Drive
Antec Neo Eco 620C
Antec 1200 (6 120mm LED fans, 1 200mm)
NZXT Havik dual 140mm fans


Thanks for input.

[Deleted]

You should technically be fine, The Antec PSU can deliver 576W, below is at 90% load with some aging but it might be cutting it close. You will need extra cables for the second GPU as I believe the Antec only comes with 1 6pin and 1 6+2 pin.

System Type:		1 physical CPU	
Motherboard:		Regular - Desktop	
CPU Socket:		Socket LGA 1155	
CPU:		Intel Core i5-3570K 3400 MHz Ivy Bridge	
Overclocked:		4000 MHz, 1.3 V	
CPU Utilization (TDP):		90% TDP	
RAM:		4 Sticks DDR3 SDRAM	
Video Card 1:		NVIDIA GeForce GTX 660 Ti	
Video Card 2:		NVIDIA GeForce GTX 660 Ti	
Video Type:		SLI	

Regular SATA:		2 HDDs	
DRAM SSD:		2 Drives	
Blu Ray Internal Drive:		1 Drive	
USB:		1 Device	
Fan Controller:		Yes	
Fans			
Regular:		6 Fans 120mm;  1 Fan 140mm;  	
Water Cooling Kit:		Corsair Hydro H80	
Keyboard and mouse:		Yes	
System Load:		90 %	
 
Minimum PSU Wattage:		509 Watts	
Recommended Wattage:		559 Watts

Maybe see what others have to say. In the even you wanna get a new one I would suggest one of these modular optins:

SeaSonic M12II 750 $100

NZXT Hale82 650w Modular $80 (2x6 pin, 2 x 6+2 pin, 53A/636W, Seasonic OEM)

[chazus]

Outside of the cabling issue, I'd say no problem. 2x 660ti at max load is like 450w, so 80% PSU load would be right around 550. 620 ought to be spot on.

[Wrestler10307]

Makes sense, I guess I'll end up buying another card then if the psu can't handle it, I'll replace it.

Thanks guys.

[vesseblah]

Since you have both CPU and GPU overclocked it's probably not enough.

[glo]

Outside of the cabling issue, I'd say no problem. 2x 660ti at max load is like 450w, so 80% PSU load would be right around 550. 620 ought to be spot on.

That's not what the 80+ ratings mean. <.<

80+ ratings are for AC to DC conversion efficiency. So a 1000w PSU at full load with an 80+ rating would be pulling 1200w from the wall. The PSUs still deliver their rated wattage regardless as long as they're of decent quality.

[Lemmiwink]

Exactly, and more importent is to look at amps on the 12V rail. Just saying it will work isn't necessarily true, as far as I can see this PSU delivers 48A on the +12V rail which should be sufficient for your system. I wouldn't have too many USB's plugged into your computer or install lots of HDD's though. I would also refrain myself from increasing the power target on these cards should you decide to overclock. You will be able to run this configuration but it will be tight under the wrong circumstances.

edit: 12*48=576W on the 12V rail. This could be better or worse depending on various factors such as temperature etc.

[chazus]

That's not what the 80+ ratings mean. <.<

I'm aware of that. I was saying that PSU's are most efficient around 80% load.. So a good 550w would be the sweet spot, and anything higher or lower would start to lose efficiency. Granted, a 620 wouldn't lose much. I wasn't talking about wattage needed, really.