gurus with 2 3870x2's: temp. difference between them?

Discussion in 'Videocards - AMD Radeon' started by KevKiev, Feb 26, 2008.

  1. KevKiev

    KevKiev Maha Guru

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    GPU:
    ATI HD6970
    Just thinking about the cooling of my 2 HD3870x2's (Overdrive shows GPU @825Mhz/ Mem 901MHz) as they seem to run pretty hot and have about a 8C difference between them. Currently they're idling at 70C and 78C respectively. For what it's worth, the dropdown box shows the hotter card associated with the monitor, so that would be the card nearer the top of my case.

    I'd welcome any comments as to the kind of temperatures, and temperature differences, other people with dual x2s are experiencing.


    Thanks
     
  2. inklimited

    inklimited Ancient Guru

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    GPU:
    Gigabyte 6850 900MHz
    Heat is rising off the lower card, and is heating the upper one?
     
  3. KevKiev

    KevKiev Maha Guru

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    I bet that's happening, but 8 or 9C? Well, I guess it could be just that....

    I've been noticing a lot of variation in temps in the x2 reviews I've seen. Granted some have souped-up coolers, but still....

    In the "Die Hard Overclocking" forum I posted a (rather noobiesh) post about o/c via bios flash v. Overdrive. In regards the heat issue, and the X2 generally, Worthy's reply is an absolute must read.

    EDIT: really should have attended HS physics... just thinkin: assuming the 2 cards would, independently, have similar temps in similar conditions, would it be a case of the lower card heating the higher one, or the lower card's dissipating heat preventing the higher one from dissipating it's own? Or is that ridiculously picky? (I can hardly believe I'm sayin' stuff like this these days. Okay, thinking about science every 10 freakin' minutes was kinda fun at first but... holy crap, I just want to shoot aliens with laser beams ferchrisakes. ;))

    EDIT 2: the gears managed to grind out another thought: I guess the difference between heating/ lack of dissipation is the difference between the upper card exceeding its temperature rating or not? Unless those ratings assume some amount of dissipation I suppose. Or... um.... okay, I gotta cut this out. It's now 4:20 and I'm on break....
     
    Last edited: Feb 27, 2008
  4. Bullu$

    Bullu$ Master Guru

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    GPU:
    R290X CFX@1050/1350
    In idle mode:
    50 and 42 degrees with a fan-profile in rivatuner(24%)
    max. 70degrees (44%)

    Without the fan-profile it hits the 90degr.
     
    Last edited: Feb 27, 2008

  5. GhostXL

    GhostXL Ancient Guru

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    GPU:
    Merc 319 6800 XT
    My card idles 55-58C...

    In full load it never goes above 76C.

    The 2nd Idles 60-62C, never goes above 76C.

    All I know is thats cool enough for me.

    Do you have a front 120mm fan or an 80 on your case kev? I have a 120mm Thermaltake blowing across the cards, into my other 120mm thermaltake in the back blowing the air out.

    I also have a fan on the top of my case blowing hot air out, and one behind my HDD bay beside my PSU blowing hot air out. This Thermaltake Armor case is great with airflow, I still think maybe the airflow of that case is whats doing it.
     
    Last edited: Feb 27, 2008
  6. worthy

    worthy Master Guru

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    GPU:
    2 ATI hd 4870 512s
    This is what I'm talkin 'bout. :)

    Nowhere for heat to stick around even with the case closed.
    [​IMG]
     
  7. worthy

    worthy Master Guru

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    GPU:
    2 ATI hd 4870 512s
    sorry about the monstrous pic!
     
  8. inklimited

    inklimited Ancient Guru

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    You could try sticking a small fan in between the two cards and see if that makes much of a difference.
    But I would still think it has to do with A) Heat rising, B) Much like a dual-core CPU, one is always going to have a higher temp due to higher load.
     
  9. Frenchlick

    Frenchlick Master Guru

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    GPU:
    GTX 480 /32"LCD
    I've got a similar fan set up to that using the same fan but smaller i have one sitting infront of the memory and the other right at the vid card used to be good when i had xfire 2900xts and seems to be ok with one card too.

    My 3870x2 idle - 52-55
    underload 70-75 depending on how hot it is here middle of summer atm.
    That's all using standard fan settings, if i crank the fan up to 40-45% on riva it sits at around 45.
     
  10. KevKiev

    KevKiev Maha Guru

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    GPU:
    ATI HD6970
    Excellent checking in to a whole thread of useful, and incredibly timed posts. I'm starting some experimenting because, after closer inspection, it indeed seems that airflow is pretty funky right around the X2's.

    From what I've read, the Cosmos maximizes aiirflow by a couple of 120mm. intake fans, on the floor and backside respectively, and a couple 120mm exhaust fans on the top. There's also a weird acrylic "tunnel" right in front of the GPUs. I may have introduced a foreign species into this environment with the CoolIT GPU cooler. I liked it 'cuz it's one of the few coolers that actually cools and doesn't just dissipate, but it's big and prevents installation of the backside intake fan (I really should have looked into that more. I thought that back fan would be preserved. Then again, I thought I had a case fan controller too, but turns out the vendor didn't connect the wires because it didn't work. And the back fan somehow fit into the invoicel. Grrrr.)

    I should have been diligent about airflow planning, although maybe there's nothing terribly wrong with a little bit of extra heat (?). But, anyway, water under bridge now. To try and see what I can improve, my plan is to alter one thing, run 3d Mark 06 while monitoring case and GPU temps at bootup and start, mid and end of program, and after a cooldown. Repeat as necessary. Just finished a run without that tunnel. (Negligible effect on the X2's themselfes, but dissipated evenly about 5C out from that area.)

    Thanks again for the comments.

    Cheers
     

  11. KevKiev

    KevKiev Maha Guru

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    GPU:
    ATI HD6970
    Removing the tunnel, the 3 empty HDD trays and the plastic top didn't have much effect on most of the case (which ws ok), but reduced that 44C area by 8C. Yet almost no effect on the GPUs! (Still would be a good idea to mod the top for venting and maybe even get another intake fan. The intended airflow is seriously out of whack.)

    Hold on while I take a step back here....

    CCC shows Crossfire as enabled, even though there's only one 3870X2 (linked with monitor) in Overdrive's "graphics adapter" dropdown box.

    That same X2/monitor combo, and a second X2, are the 2 items in Overdrive's "select GPU to configure" dropdown. (I had thought this + "enabled" meant CF)

    When I'm in Overdrive and toggle between those two in the "GPU to configure" box to check out the temp. gauge ... am I toggling between the X2's or the 2 GPU's on the X2 that feeds the monitor? In either case, I guess, from which 2 of the 4 GPUs are the temperature reading coming from?:bonk:
     
    Last edited: Feb 27, 2008
  12. KevKiev

    KevKiev Maha Guru

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    GPU:
    ATI HD6970
    I knew I'd read about/seen something like this before, so CCC is recognizing my 2 cards (pic from a recent review).
    [​IMG]

    I think I may have been confused after reading this test of a single X2 where Overdrive was reading each GPU:

    "To first look at the temperature of the GPU at idle and full load we used Catalyst Control Center’s Overdrive tab. In order to utilize this tab we had to plug in a 2x4 (8-pin) power connector. In Overdrive you can select both GPUs to see the temperature for each one. At idle they were the same temperature, at full load we noticed a few degrees difference between them, and so below we used the temperature for the hottest GPU. "

    So it appears both cores have a temperature sensor on them but for Crossfire you just hook up one. Reasonable enough. (I wonder.... would there be some reason to prefer hooking up one rather than the other?)

    And here's something out of the blue: at least back in '04 ATI set up Overdrive to overreport temps by 20 degrees:

    http://www.firingsquad.com/hardware/catalyst_4.1/

    Now that would be beautiful. (Edit - they appear to be talkin' Celcius. Wow.)
     
    Last edited: Feb 28, 2008
  13. Smiling Cat

    Smiling Cat New Member

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    GPU:
    HD3870 Crossfire
    I run two HD3870s in my P182 case and before I finally got Riva Tuner I noticed they run around 77-76 Celsius. Idle and while under load never changing in Catalyst control. Also other monitoring programs like PC wizard would pick up both cards, but the firsts cards temp carried directly over to the second.

    The fans do not seem to spool up adequately in 3d clock settings in games. I have had Crysis lock up around half way through the game and decided to monitor them. I have still yet to go through and see what temperature they top out at though letting the driver control fan speed until I get a Crysis to crash.

    If I set the fan manually in Riva Tuner it idles around 45C with fan speed set at around 35% which is far louder than I have ever heard them while under complete load.

    At 100% fan speed they even out at around 60C under load. Very loud by comparison to the default speeds although they run much cooler and are completely stable. Have only been toying around with Riva Tuner just a short while because currently it will only show me one cards core temp at a time.

    Although the difference is probably 3-6C higher on my upper card under load, with the upper card running hotter. Although because of the case configuration the lower card is pulling in cooler air from the bottom compartment where a 120mm is bringing in cool air to the power supply, that might be the reason.

    Can't wait for the next Riva Tuner with better support for the HD3870 series cards.
     
    Last edited: Feb 28, 2008
  14. KevKiev

    KevKiev Maha Guru

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    GPU:
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    Yeah, I think it's time to get Riva-d. I tried getting into my BIOS to see about fan control/ temps, but I can't seem to get the ASUS utility run properly.

    I'm beginning to see why people who are really into pc's and gaming build there own rigs. (Ironic that trying to avoid getting involved in the details by buying a pre-build has ended up forcing me to do just that. And, for more irony, I realize that's a good thing.)
     

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