OC i7 920 to 3.8 ghz and crossifre 4890 to 950 mhz each - what PS?

I am planning on buying a liquid cooled system and then to overclock it to 3.8 ghz and the video cards from 850 mhz to 925 or 950 mhz each. I was wondering if an 800 W PS would be sufficient to power the computer with a heavy load on the video and cpu.


- Panos -
14 answers Last reply
More about crossifre 4890
  1. Actually 800W PSU would be suffice even for an O/C i7 + 2x HD 4890 in crossfire...
    But more importantly the make and the quality of the PSU is that matters...
    Any PSU from these manufacturers would be the best option...
    Corsair/ Seasonic/ PCP&S/ Silverstone / Antec Signature/ Antec CP/ Antec TP
  2. Just to be clear: you've got two 4890s? In any case 800W is more than enough, though if you want to go even higher than what you're planning, you should consider a 1000W PSU, to future-proof your rig.

    Also, what is your water-cooling kit? How much power does it consume?

    EDIT: What gkay09 said!
  3. ^ Well a Corsair 850TX can easily handle a decent water-cooled PC with the above setup...
    A 1000W would be an overkill...
    Check this...Select all the components an capacitor aging to 25%

    And @polyzp you wouldn't need liquid cooling to reach that speed...
    Either TRUE eXtreme or the Noctua SSO and preferably i7 920 D0 stepping can easily allow for such a overclock
  4. I had said the 1000W to be an overkill because if you check the TOM's articles on GTX 295 SLI and the Cyberpower PC review, you can see that the GTX 295 sLI easily ran on a 1000W PSU and for your setup, its like using a single GTX 295 (Maybe add few more wattage)
    and For the X4 955 + 2x HD 4890 setup, cyberpower had powered that rig with just a Corsair 650TX...and that PC did complete the stressful benchmarks without having problems in the power dept...Though the 750W would have been a sweet spot as the reviewer had pointed out...
    So for your setup, the Corsair 850TX is a very good option...
  5. i dont want to pay an extra 74 dollars for a crossair. The current PS is advertised only as:

    800 Watt -- Power Supply

    800 Watt Version 2.91 with Ultimate detachable connectors/140mm Ultra- Silent Cooling LED Fan with Auto speed Control/20+4 Pins/QUAD +12V supported//SATAx 6/ nVidia SLI Certified Ready)/OVP,UVP,OPP supported.

    on IBuyPower, with no further info.

    Will this be sufficient?
  6. the liquid cooler only takes 2.5 W it says
  7. I own 2 corsair PSU's and haven't had any issues with them. I don't know much about Ultimate but haven't heard anything bad about them.

    I would always pay a little extra for a better PSU. I know $74 may not be a little but I just got a Corsair 650watt for about $65 after MIR
  8. Always buy a power supply of a reliable brand. If it goes.... so can everything else.
  9. polyzp what the good people that are trying to help you in here is great advice, sense you are buying this pc from IBuyPower and you are picking out what parts you are putting in the pc.and the 800 watt is $ 85.00 for a no name psu which if it were me I wouldn't buy either.on the site they do sell the corsair antec etc.it would be a good idea just to go back in their and pick one of the better brand name psu.you want be sorry and it not going to cost you anymore than the no name psu. and the water cooling idea (gkay09) explain to you is correct.I have got the true on mine and it is great.

    the psu is the most important part in a pc.good psu =happy pc

    ^ +1 on all the posters. polyzp they are all correct
  10. Alright, so you guys convinced me that i should pay the extra 70 usd for the crossair 850 W PS.

    Id rather do that now then risk having to reship it out for repairs .. to the us from canada = 90 usd bak n forth = 180 usd.

    - Panos -
  11. Plus i felt a bit uneasy with only 800W powering a 3.8 ghz i7 with 2 overcloked video cards working in crossfire. and 2 liquid cooled radiators wth two 120mm fand PLUS with TWO more 240mm fans.
  12. fans*
  13. polyzp said:
    Plus i felt a bit uneasy with only 800W powering a 3.8 ghz i7 with 2 overcloked video cards working in crossfire. and 2 liquid cooled radiators wth two 120mm fand PLUS with TWO more 240mm fans.

    Why does everyone on this site overestimate how much PSU we need by usually over 50%? Do we just love to give more money to the PSU brands? Do we not realise that most better PSU's run more effeciently at 60% or greater of their rated load? Do we love forking over more money than required to the power companies?


    Xbitlabs went to great time and expense to really do some thorough testing. Their results are, to say the least, a bit more than a bit surprising at least to me.
  14. Hey all that sounds good , but you left out a good PS which I have tested and is a good choice also, its the Zalman 750w 80+bronze certified heat pipe cooled SLI certified modular PS which powers my rig just fine with my i7@4.5hgz 2x9800gt's in SLI overclocked to 740/999 and 3xHDDs 6x fans and a water cooling system!


Ask a new question

Read More

Intel i7 Overclocking Product