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LeeDye
08-28-05, 01:24 AM
Well, I went ahead and purchased 2 ZALMAN VF700-CU's for my 7800 GTX cards.
Installed them with a nice thin layer of AS5. Powered up the computer and to my dismay noticed that the bottom card gets VERY hot under load. How about over 100 degrees and severe artifacts all over. Card one stays at a nice 70+ degrees under heavy load. Case is a well ventilated Lian li case with side off.I swapped cards and it resulted in the same. This is with no overclocking.
With stock coolers the bottom card never got this hot. Thought I would share.
Here are some pics

eva2000
08-28-05, 01:40 AM
weird stuff as folks had no probs with VF700-CU and 2x 6800Ultras and they're hotter than 7800GTXs

if you use zalman fan bracket or fan over first card closest to cpu socket does temp drop ?

AthlonXP1800
08-28-05, 01:49 AM
Maybe VF700-CU is only work with 6800 cards, not 7800 because of different PCB layout?

LeeDye
08-28-05, 02:12 AM
CPU is generating no heat according to my pyrometer as it is watercooled as seen in pic. Very cool in that area other then the bottom of the cards which are HOT!
I tried other thermal compound as well. Same result. The top card is producing too much heat for this setup. This is the same result in the article I posted a link on in another thread.
I wonder if a short PCI slot cooler would help things? Otherwise back to stock where it ran much better.

toxikneedle
08-28-05, 02:17 AM
In the other thread about replacing stock coolers for 7800s theres a discussion about how effective the zalmans are in SLi. Seems like they get hot when theres no airflow (bottom card). It's possible that their design isn't best suited for SLi. But dunno for sure if that's a fact or not.

LeeDye
08-28-05, 02:23 AM
In the other thread about replacing stock coolers for 7800s theres a discussion about how effective the zalmans are in SLi. Seems like they get hot when theres no airflow (bottom card). It's possible that their design isn't best suited for SLi. But dunno for sure if that's a fact or not.

Here is the link again to that review. My results are spot on to their experience. They are reviewing the aluminum version whereas mine were the all copper versions.

http://www.insanetek.com/index.php?page=zalmanvf700alcu

ViN86
08-28-05, 08:16 AM
is there a way you can get a fan in behind that bottom card and open a PCI slot bracket so it can remove the hot air?

BrianG
08-28-05, 08:18 AM
Well, I went ahead and purchased 2 ZALMAN VF700-CU's for my 7800 GTX cards.
Installed them with a nice thin layer of AS5. Powered up the computer and to my dismay noticed that the bottom card gets VERY hot under load. How about over 100 degrees and severe artifacts all over. Card one stays at a nice 70+ degrees under heavy load. Case is a well ventilated Lian li case with side off.I swapped cards and it resulted in the same. This is with no overclocking.
With stock coolers the bottom card never got this hot. Thought I would share.
Here are some pics
It may just be the picture, but the bottom cooler looks like it is not set properly, raised in the back a bit. Is there something behind that card, like a mobo header cable or fan connector, causing it to tilt off the GPU?

eva2000
08-28-05, 08:32 AM
It may just be the picture, but the bottom cooler looks like it is not set properly, raised in the back a bit. Is there something behind that card, like a mobo header cable or fan connector, causing it to tilt off the GPU?
yeah i noticed that in the 2nd pic attachment - looks like that blue sleaved cable under the bottom first card is tilting the heatsink

ViN86, best way would be using zalman fan bracket and a fan positioned so it's air flow covers that first card closest to cpu socket

With stock BFG 7800GTX heatsinks and 4x80mm adda case fans very low noise - but will work with any heatsinks really

http://fileshosts.com/videocards/7800GTX/BFG/ADDA/ADDA_7800GTX_01.jpg

attached image of cropped area that i see the tilting

BrianG
08-28-05, 09:39 AM
yeah i noticed that in the 2nd pic attachment - looks like that blue sleaved cable under the bottom first card is tilting the heatsink

ViN86, best way would be using zalman fan bracket and a fan positioned so it's air flow covers that first card closest to cpu socket

With stock BFG 7800GTX heatsinks and 4x80mm adda case fans very low noise - but will work with any heatsinks really

attached image of cropped area that i see the tilting
Is it me or is that Ramsink above look like it is touching the core heatsink?

It certinaly would explain why the problem stays with the slot and not the card...

$n][pErMan
08-28-05, 12:43 PM
Not to state the obvious.... but could it be possible you did not seat the heatsink right on the on GPU?? I had a similar problem with my zalman for my CPU ... it would get very hot. I took it off and reseated it and boom... it worked great. Apperently some of the thermal paste got to thick at one point and was causing the problems.

LeeDye
08-28-05, 12:45 PM
yeah i noticed that in the 2nd pic attachment - looks like that blue sleaved cable under the bottom first card is tilting the heatsink

ViN86, best way would be using zalman fan bracket and a fan positioned so it's air flow covers that first card closest to cpu socket

With stock BFG 7800GTX heatsinks and 4x80mm adda case fans very low noise - but will work with any heatsinks really



Thanks for the advice everyone. The heatsinks are not tilted in any any and they are of course planted firmly on the core. Perhaps the angle of the shot gives that impression. I wish it was that wasy. :D The sleeves place no heat,restrict, or pressure on the heatsink either. That was the first thing I checked during installation and rechecked afterwards. I did check the RAM sinks and even removed them which helped but only a couple of degrees. I will take any little bit I can. Not enough to make much of a difference. Airflow is critical. A 2.8" PCI fan would most likely assist very nicely as the open portion of the heatsink is facing the PCI slot.
I removed the PCI plate and the temps dropped even further,but still nowhere near stock. The difference between the top core and bottom core is huge in respects to temps.
I do appreciate the advice, keep them coming. Anyone know of a 2.80" PCI fan?

jAkUp
08-28-05, 12:49 PM
He said that he switched the cards with the same results...

FraGTastiK
08-28-05, 01:05 PM
I think there are two factors here.first is the small gap between PCI-E slots in DFI board and second is the fact that 7800's back side produces a noticable (but not unhealthy) amount of heat especially when OCed.(ram chips+the GPU backside).

in my case the OCed 7800's backside heat raised my CPU temp a bit.I had to strengthen the air flow to remove the backside heat effectively.well i would've done it anyway,should've maxed the airflow before.

so basically your bottom card is just recieving hot air in very close proximity almost absorbing it all.kinda makes me think to go for stock cooler or water cooling for the bottom card or blowing air in the gap form top side.

LeeDye
08-28-05, 02:05 PM
I remounted the lower fan/heatsink in another location on the card and this helped even further. See pic. Probably due the the open end of the heatsink able to bring in cooler air from the front of the case. After a run in HL2 the temps for the lower card is 87-90 degrees. Still more than stock by far. Going to put the old stock unit back on with some AS5 and return the product. Too bad as it LOOKS good.

BrianG
08-28-05, 02:21 PM
Interesting. Let us know how the remount goes and what kind of temps you get after with the AS5...

LeeDye
08-28-05, 02:22 PM
Interesting. Let us know how the remount goes and what kind of temps you get after with the AS5...

Workin on it right now. Will do.
;)

LeeDye
08-28-05, 03:05 PM
I installed the OEM unit back on the lower card with some AS5 as well.
Max temps under HL2 and FEAR resulted in 63 top card and 74 lower card. :D Much better. Will return top card back to stock as well and post final temps. AS5 is still curing so I am sure things will only get better.

LeeDye
08-28-05, 03:46 PM
Everything back to normal. Ran HL2 and FEAR which really heats up the cards. Top card under load is 70 and bottom card is 78. This is with the side panel back on.I will look out for other solutions. I may have to just watercool those GPU's as well. Well, not all is lost. Hopefully it will save someone some time. ;)
Lee

toxikneedle
08-28-05, 05:11 PM
Everything back to normal. Ran HL2 and FEAR which really heats up the cards. Top card under load is 70 and bottom card is 78. This is with the side panel back on.I will look out for other solutions. I may have to just watercool those GPU's as well. Well, not all is lost. Hopefully it will save someone some time. ;)
Lee
Yeah I was planning on doing the 2 zalmans for SLi. But after reading your thread and the other one, I sure won't. I dunno if I'll even replace the stock cooling. Maybe I'll get 2 silver ACS3 cooling kits from eVGA to match my case, but not for cooling.

$n][pErMan
08-28-05, 05:45 PM
Hey LeeDye ... I see you have a nice flatpanel (what looks like a TV not a monitor) on your wall. I noticed in one pic you had a game running on it. What I care to ask is how you like gaming like that and how is the picture quality?? I'm looking to mount one on my wall for some super sized gaming and if you have any suggestions or perhaps what model yours is .. let me know :)

PNY7800GTX
08-28-05, 06:17 PM
Thats DOOM III on the monitor ;)

haha sorry I thought you had asked what game too...

LeeDye
08-28-05, 07:03 PM
[QUOTE='$n][pErMan']Hey LeeDye ... I see you have a nice flatpanel (what looks like a TV not a monitor) on your wall. I noticed in one pic you had a game running on it. What I care to ask is how you like gaming like that and how is the picture quality?? I'm looking to mount one on my wall for some super sized gaming and if you have any suggestions or perhaps what model yours is .. let me know :)[/QUOTE

It's a 30" LCD and it is great! The pic has F.E.A.R running on it. The LCD is very good with no ghosting. This coupled with the Klipsch speakers gives a very nice gaming environment. Max resolution of the unit is 1280*768 so I run everything maxed out. AA,AF,etc..
:D

BrianG
08-28-05, 07:08 PM
It's a 30" LCD and it is great! The pic has F.E.A.R running on it. The LCD is very good with no ghosting. This coupled with the Klipsch speakers gives a very nice gaming environment. Max resolution of the unit is 1280*768 so I run everything maxed out. AA,AF,etc..
:D
Is that the Dell?

LeeDye
08-28-05, 10:08 PM
Oh no. I don't normally buy Dell anything. The laptop is good though-far cry from the junk Dell produced prior. The monitor is a Olevia. Though I do have a Dell 19" LCD that is pretty decent.