Hey All, a little help/advice needed.


I wanted to ask some advice or maybe I need help or pointing in the right direction. I have just been testing or rather burn testing my system and I am getting some things I never got before. I have just upgraded the graphics card to 2 480's in SLI so I thought I would test if my system had enough power. OK I'll start with hardware setup. Most of the PC, that is everything except the Graphics cards have been in the system since October, although I added a new power supply in January.

Antec 1200 Case
Corsair HX850 Power Supply
Intel i7 920 Overclocked to 4Ghz.
6Gb Corsair XM3 Ram @ 1600Mhz.
Gigabyte EX58 UD5 Mobo (all the overclocking was set up by Overclockers the company I brought them from, the setup was sent backa few times to get "stable" but has been fine).
Corsair HD 50 CPU cooler
2x Zotac 480 GTX (In Sli but Stock no Overclocking).
1x 150Gb Raptor.
1x 1TB Seagate Drive.
1x 250Gb Samsung Drive.
1x 2400rpm 120mm fan.
4x 1600rpm Fans (2 of which are case fans).
1x 200mm Case Fan.
1x DVD RW.

First of all there are no cooling issues that I can see, except the stupid heat from the GTX's lol. So here's what I did to burn test and he in lies my dilema.

I opened up 4 instances of Othos, set the affinities to split across the 4 Cores/8Threads and set 3 as blend tests and one as a CPU test.

I installed Furmark.

I started Core Temp and the EVGA tool for monitoring and set Task Manager to watch the performance.

When I started just Orthos I could see I wasn't getting all the cores etc to 100% and after several attempts I could see Orthos was crashing. I have never had this happen. I eventually got it to run a stress test on all 4 cores/8 threads by setting the test to stress only the CPU. Then started Furmark and the system locked up. At this point despite all the article I read saying I could run 2x GTX 480's with the HX 850 I was thinking not enough power or Ram problems.

I restarted the PC and set up Orthos again but htis time to test the Ram and CPU as per orignal setup and it worked fine. I then started Furmark and sterted it in multi GPU stuck it in fullscreen and at this point I could see that I was gettin 100% stress on everything and it ran fine. I did check the temps on the cards and despite the fanse being at 80% one was reading 89 (this i expected) the other was 97 (this is didnt expect) however I did have the AA set to 32x.

I am not sure tbh what I am asking but the fact that I did get the setup to work suggests to me all is ok or rather I have the power, but then again I had problems getting it all to run. I have no other issues anywhere else I can see and game all run fine. So I guess I am looking for opinions more than anything.

Thanks in adavance.

Raz :)
6 answers Last reply
More about help advice needed
  1. google for PRIME95 and try that as a CPU stress tool. You only have to run prime once to peg all 4 cores to 100%

    When I do a worst case scenario with your equipment and a new PSU I get 880W and after a couple years aging I get 1000W.

    Corsairs are underrated so its my guess is you are OK now but are running pretty close to the limit.

    Probably a good idea to remove that outdated 250GB HDD if you can

    Backing off the overclock would be a good way to check power if you start having problems.
  2. The difference in GPU temps from one card to another is because of the fan orientation on the cards themselves.

    The top card is going to be affected by the heat of the lower card.
  3. The 850 watter is undersized for twin 480's. If you check the nVidia site, the lowest wattage PSU listed is 900 watts.. Using the PSU calculator on the Antec site with twin 480's and a 40% CPU OC, I hit 900 watts w/ 10 % cap aging, your case fans,1 HD, 1 SSD and 5 USB devices connected.

    I did notice that the CP-1000 is SLI certified for the 480's w/ twin cards which kinda surprised me at 1st as it only has a few more amps than the CP-850. You might try running OCCT's torture tests and monitoring voltage .... the PSU torture test has been known to kill PSU's of questionable quality....the HX series **should** therefore be immune to such a fate.
  4. Hey Guys,

    Thanks so much for the replies. OK so I changed over to Prime 95 and while it only tested 3.48Gb of Ram it did test the CPU at max like you said, thanks dndhatcher for that suggestion.

    The test ran fine with a second or so dip then all was ok again. Furmark was reporting 72fps until the dip when it went to 28fps then back to 75fps.

    As for the Antec PSU site I have just done it and it says 805W, thats with 3 HDD's, all the fans, 3 sticks of ram and the overclocking. I do note I have no other cards in the card. I also added 10 USB devices and made sure the 480's are SLI.

    I do note also that the Stock VCore is listed at 1.37 but mine is set at 1.28 all the time I use Core Temp and CPU to confirm.

    I better look into a 1000W soon though. Thanks again all, any further comments or suggestions welcome.

  5. I ran your specs through a PSU calculator and got:

    Minimum PSU Wattage: 796 W
    PSU Wattage: 846

    Your PSU is underpowered for your setup, I'd recommend 1000W+
  6. Thanks, I will see if I can sort out getting the 1000W version of the one I have. Cheers for all the input.

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