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660ti, would i need a new PSU

Last response: in Graphics & Displays
February 21, 2013 11:58:31 AM

Hi guys,

so today i was about to order a 660ti and i thought i better check my psu, i was thinking oh it will be ok this pc cost £800 from pc world (LOL! worst idea ever but then i was forced to buy from there) expecting to have the bare minimum of a 500w psu. now i opened it and found these figures... i am not sure what they mean so if someone could just say if it will run a 660ti or not that would be great, if it doesn't run it then i have to downgrade to a 660 SC and get a new psu with it :p 

Channel well technology
DC/OP 405w
+5v 20.0A
+3.3v 24.0A
+12v1 17A
+12v2 17A
-12v 0.3A
+5vsb - don't know if there was meant to be another number i might have forgot to put it down


If i have to get a new power supply these 2 are the 1s i have been looking at

More about : 660ti psu

a b Î Nvidia
a b ) Power supply
February 21, 2013 12:18:25 PM

That PSU should work just fine, in theory. Based on Nvidia specs, the standard version of the 660 ti video card has a max wattage rating of 150W:

They list a minimum 450W PSU because some PSUs are underpowered on the 12V rail. They want to cover most situations with this. Your PSU has enough on the 12V rails. Based on the info you've provided, each 12V rail can handle a max of 12Vx17A=204W each with a total of 405W combined (possibly?). If you could show a picture of the label on the PSU or provide a model number, we can better evaluate the situation.
February 21, 2013 12:21:27 PM

Thanks for the reply, i believe this is my model number....PUFP405P
Related resources
February 21, 2013 12:25:37 PM

It won't be 405W combined as that is the practical max of the PSU overall. Rather, the PSU can put up to 204W on either rail but its total power output must remain at or below the nominal 405W. As the system will draw power from the other rails at all times you will never be able to achieve 17A on each 12V rail simultaneously. You couldn't safely do this even if there were no other power draw- as that's 408W - 3W more than it apparently allows! :D 

Essentially we're looking at a reasonable front-end design (where the 3.3V, 5V, 12V are regulated) with an underpowered back-end (where mains is brought down to useable DC) to feed it.

OP, consider changing your PSU. Split rails (12v1, 12v2 etc) are horrible things anyway, they are impractical more often than not. Get something like a Corsair CX430W or a CX500W V2. Cheap, good quality, single large 12V rail for no-nonsense juicing supply.
a b Î Nvidia
a c 126 ) Power supply
February 21, 2013 12:55:43 PM

Split rails are FINE! In fact, when properly current-limited (most are), they are safer than a single more powerful rail. Just keep in mind that they won't be additive; for example, you'll have 24A total on +12V, with each rail limited to perhaps 16A-18A; you can load one rail up to 18A or so, but the total still can't exceed 24A. The idea of power being "trapped" on an under-utilized rail is thus a myth.
The Corsair V2 "Builder" units are so-so PSUs; made by CWT, not Seasonic, using some inferior Samxon capacitors known for early failure. Look for PSUs built by Seasonic (their own, XFX, some Antec), FSP (their own, some Antec), Enermax/LEPA (their own), or Superflower (new Rosewill and new Kingwin).
Furthermore, Coolermaster PSUs are generally near-junk; in particular the GX-650 was summarized by HardOCP as a "polished turd in a box."
a b Î Nvidia
a b ) Power supply
February 21, 2013 1:06:15 PM

Marcus56 said:
Thanks for the reply, i believe this is my model number....PUFP405P

I can't readily find definite specs on the power supply so I can't conclude anything about the combined output of the two 12V rails (unless you can post a pic).

As a result, I'd recommend the purchase of either of the PSUs you've listed or you can get by with this that provides 456W on the 12V rail for sure:

a b Î Nvidia
a c 126 ) Power supply
February 21, 2013 1:36:22 PM

Yes, that Seasonic-built XFX would be a great choice for a 660 or 660Ti.
a b Î Nvidia
a b ) Power supply
February 21, 2013 1:50:43 PM

Marcus56 said:
a friend suggested looking on novatech and this 1 caught my eye, onus suggest XFX.

Would that be ok for a 660.

Thanks for replys so far.

Great deal. I'd definitely pick one up then. Like onus said, it's made by Seasonic. Seasonic makes all of their power supplies:

Seasonic is among the best PSU manufacturers out there.
February 21, 2013 4:52:34 PM

I've been using my Antec TruePower 850 for 3 years now and went from a 480 GTX on a Core 2 Quad to an Ivy Bridge i5 3570k with a 660 Ti with no issues.
a b Î Nvidia
a c 126 ) Power supply
February 21, 2013 5:12:49 PM

That Antec 850W PSU would be sufficient to run THREE GTX660Ti's; it's way overkill.
a b Î Nvidia
a b ) Power supply
February 21, 2013 6:03:08 PM

February 22, 2013 10:21:59 AM

Just to update you all, first of all thanks for the replys, my card is already here (660 Superclocked in the end) power supply isn't expected to be here till tuesday. Would it damage the computer if i tried the 660 with my current system?

Something i should had added to earlier posts but forgot then when i did try to edit at one point it said i couldn't, is the rest of my specs if it affects anything which are

8gb Ram @ i beleive 1333mhz
2tb hard drive
4 case fans
i did in the end find my motherboard which is -
a b Î Nvidia
a b ) Power supply
February 22, 2013 10:28:42 AM

Personally, I'd try it. Not saying that's the best course of action because we don't know the combined wattage rating of the 12V rail on your PSU, but I'd still give it a go.
February 22, 2013 3:45:02 PM

It's all working at the moment, no problems so far, had a quick go on GTA4. Really not sure if i do still need a new power supply though :p  as it still hasn't been dispatched i am thinking about cancelling to be honest

But yeah, thanks for the replys guys been a great help!
a b Î Nvidia
a b ) Power supply
February 23, 2013 12:04:06 PM

Use a tool like EVGA's Precision X and turn on the On-Screen Display. Check that you're GPU usage for both cards is reaching near 100% while playing GPU-demanding games on ultra.

If that's happening, it means your cards are getting the power they need and you can cancel your PSU order.