Evga Gtx 660 ti 3Gb SLI

I have been reading around, and there has been mixed replies to people asking about using a 650W supply for 660 SLI. Most says it's OK, but I would like to be sure.

The part# is 03G-P4-3663-KR for those interested. I am currently running a rig with i5-4670k.

I haven't started overclocking yet.
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  1. I run the 2GB version of the 660 Ti in an SLI configuration, and had to upgrade from a 750W PSU to do it. I went a bit overboard and got a 1300W PSU to give myself some room to grow, but I'd suggest you get at least an 850-900W PSU to make sure you can power all of your peripherals that require it, and to have room to upgrade your PC and for overclocking.
  2. The power supply is the main part of the computer that has the potential to fry EVERYTHING if it's not up to spec. A power supply from a good brand such as Seasonic with a 650W rating is probably plenty, but remember the rating is a maximum output among all voltages simultaneously. It's worth buying one with some extra headroom. I personally like power supplies that are fully modular and carry 80+ certification for efficiency. Buy the best supply you can afford, and it will serve you well.
  3. Agree with the above^. Get the best PSU you can from a good manufacture. Also make sure that you are getting a PSU that has some head room. I have 800w PSU in all of my systems but I am running Crossfire/SLI setup in all three.
  4. your amount of wattage is fine. It will depend more an the amount of amps on the 12v rail. If you start overclocking you will probably need anew power supply but that will only come into effect when you are benchmarking.

    what is you power supply. you will need 40 amps on the 12v rail
    both of your cards have a max draw of about 300 watts
    40amps * 12v rail = 480 watts
    so a 40 amp 12v rail will work.

    even if your CPU is pulling 125watts from the 12v this leaves you some headroom
    this would leave another 200+ watts for the rest of your system and you should be fine
    80+ certification means nothing except that you use less power from the wall.

    what we care about is you ability to push that wattage through a 12v rail, the amount of ripple in the line (how clean or consistant that voltage is, does it stay right at 12v or does it push to high and therefore fry your equipment)

    what is your power supply
  5. My current PSU is a Corsair, so I would think it qualifies as a good PSU?

    I was also reading this:
  6. 150watts per gpu

    give me your exact model and i will check the amps
  7. Sorry about the short reply previously, I was trying to find the exact model before editing my post but you got back before me :P

    It is the Corsair TXM 650W Modular PSU. It claims to be modular, but is actually semi-modular.
  8. 54 amps on the 12 volt rail or
    54*12v rail=648 watts

    so if there ever was a power supply that would do it then this would be the one
  9. I have went through and looked at my 3 other favorite reviewers and I cannot find a single system that breaks 400 watts with an overclocked 660ti.

    that means you have 250 watts to use for another 660ti, you will never hit that number.

    I think you are safe.

    If you massively overclock everything in your system sure another 100 watts would be comforting but I do not think it is needed.
  10. I am going to call it a night (it is sexy time). If you have any other questions i will answer them tomorrow or maybe tonight if I come back down for another beer.
  11. Guru3d recommends a quality 700 watt PSU at minimum for GTX 660 Ti's in SLI. A lot of people try to cut it close and go through a complex set of calculations to get the bare minimum they think is necessary. That is a good way to end up with not enough power and/or a stressed PSU. You need more than the minimum if you plan to overclock at all, and leaving yourself some power headroom is just good common sense. Do yourself a favor and trust Guru3d's recommendation.,7.html
    •GeForce GTX 660 Ti SLI - On your average system the cards require you to have a 700 Watt power supply unit as minimum.

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

    There are many good PSUs out there, please do have a look at our many PSU reviews as we have loads of recommended PSUs for you to check out in there. What would happen if your PSU can't cope with the load:
    •bad 3D performance
    •crashing games
    •spontaneous reset or imminent shutdown of the PC
    •freezing during gameplay
    •PSU overload can cause it to break down
  12. These are some very mixed replies, but if a new PSU is needed which would you recommend? If I do get a new PSU I want it to be fairly future proof.
  13. My 660Ti's and 2600K are running on a seven year old 620w PSU that was running SLi'd 560Ti's before that and SLi'd 8800GT's before that and before them it was running SLi'd 7900GT's, your PSU is good enough and you don't need to replace it.
  14. sure it is cutting it close but even by that article they say a 450 watt power supply for one 660ti, then another 250 watts for a second 660ti when there own test show a max wattage use of 134. some simple deductive reasoning will tell you that this calculation is off base. maybe they are not taking into consideration the average person knowing some simple rules about the relationship of amps to watts.

    I will pick a couple good power supplies while i finish my beer and post the actual manufacturers also
    750 rose will hive sirtec 54 amps 12v, more power but no more power on the 12v rail $80
    xfx 750 750 w/ 62 amps on the 12v rail. this will give you another 100 watts on the 12v rail $90
    all xfx are seasonic
    corsair 750 by channel well, 62 amps on the 12v rail so 100 more watts on the 12v rail $90
    seasonic 750 52 amps 12v rail. $100

    these are all good and not needed in my opinion.
  16. Of course a major publication is going to over recommend a power supply because if they did not all the idiots would come crying about I bought a raidmax 650 watt power supply and it doesn't work. once you hit the 750 plus wattage it is much harder to find a power supply without enough amps on the 12v rail. they are just covering their asses. math and science always hold up and until somebody can add up enough wattage to prove that 650 is not enough then they can go kick some dirt.

    I do not mean this to be taken personally but I spent some time adding up allot of wattages from several sites and I do not see how you are going to break 650 watts unless you are running furmark and prime 95 simultaneously. If you were to try this you deserve to have your computer burn up btw.

    fyi here is a link to check manufacturers,2913-8.html

    you can also check other ways but this is easy
  17. Here's the thing to remember when companies recommend a PSU wattage, they have to overshoot by a healthy margin to avoid bad press or maybe even litigation. By my calculations a 600W PSU can sli 660's with a 125W CPU with some headroom. However, it does not leave that 100W cushion that many prefer. This is why other users will say "yes, 600W will suffice" but nVidia recommends a 700W minimum because it doesn't look good if a person follows a manufacturer's recommendations and still fries their system. It's CYOA syndrome (Cover Your Own Ass). These days to take a risk and fail inevitably involves punishment for someone, so everybody involved needs to be able to say they tried to prevent the mishap or else they are guilty by association.
  18. May I ask what kind of potential damage if any am I looking at? Is it 'potentially' that destructive?
  19. P K said:
    May I ask what kind of potential damage if any am I looking at? Is it 'potentially' that destructive?

    I don't think you going to see any damage as your PSU is more than capable of running a 660Ti SLi rig.
  20. If you are really worried you need to find a good review and see what the ripple load tests look like. If it produces a good clean signal you have less to worry about then if you get a new power supply that a worse ripple load test.

    can you link your exact model from corsair website

    the the old version is a CWT manufactured and seems to kick in OVP at around 760 watts
    the 2nd newer version is a seasonic.

    I do not feel like reading to many reviews without knowing your exact power supply. the old CWT was a good unit from what I have read so far keeping an over 80% efficiency right up to 100% load with very little ripple on full load. also seemed to have all japanese caps rated to 105C
  21. P K said:
    May I ask what kind of potential damage if any am I looking at? Is it 'potentially' that destructive?

    If a PSU is overloaded and fails, the possible damage ranges from a destroyed PSU to starting a house fire. If your PSU doesn't automatically shut down in case of failure, I believe the most common result is a fried mobo and CPU. The house fire is admittedly quite rare, but possible.
  22. Hmmm, does this fail to to shut down scenario only happen to badly made PSUs or could it also possibly happen to my Corsair TXM 650W?

    So finally are the possibilities of frying a mobo and CPU very high, or just a remote thing that 'could' happen.

    Anyone heard of any Corsair TXM 650W accidents recently?

    Unfortunately I'm not exactly sure whether it's the enthusiast series or normal.

    In short, its either CP-9020002-UK OR CP-9020039-UK. It's most probably the CP-9020039-UK, but I need to go check again.
  23. There's a list of potential problems that can occur with an underperforming PSU in my post above.
  24. bad power supplies blow things up that is why we recommend to get good ones
    this one has:

    Active Power Factor Correction (PFC) with PF value of 0.99
    and short circuit protection provide maximum safety for your critical system components

    if these solutions do not work then nothing will.
    and do not waste your time with power strips either because fuses just stopped working also.

    house fires often happen when you get struck by lightning so move underground but make sure it never rains where you are.

    the last article i read on the older model tx said that it continued to perform right up to 750 watts.

    please let me know when you know your exact model and I will scour the web for some hard data on when these power supplies tend to fail.

    many are often underrated just so that they can keep there 80%+ rating. eventho everyone who knows anything about power supplies knows that the certification means nothing but it helps them sell so they put it on there
  25. The PSU part# is indeed CP-9020039-UK.
  26. Best answer
    so theis tx650m is a hard one to find good reviews for

    you will have to use a translating service for this chinese website but there review is very indepth and they use good tests and good methodology. they are using a 220v test which is a little friendlier.

    this unit will produce right up to 110% of stated manufacturer output while maintaining a 85% efficiency. This unit is a 710 watt power supply.

    feel free to read through the article. most of the load line test are on the next to last page and before that you will see a complete breakdown of components.
  27. i believe all of the above links are for a different power supply and not the tx650m. if you look a the pictures or c/p the product code the OP gave us it links to a different model.

    the above is the model that shows up if you type that product code into the corsair website.
  28. Thanks for the help!
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