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Sapphire 5850 MemIO VRM issue

Posted: Sun Aug 08, 2010 6:27 am
by Darkmaniak
Hello!
I have a problem with my ATI5850 reference PCB:

My Accelero s1 rev2 heatsink +12cm fan and a VRM-R4 heatsink can take all the temps under 55° with no problems.

But there is a VRM that no heatskins can cool down, i'm talking about MemIO, the VRM that manage the memories (that's what an internet site says)

as you can see is not in a good spot, the not-reference PCB is better (5850 non reference is 5870 reference)

Image

that's what i did:

Image

i cut the original cooler so i can use the accelero, the vrm-r4, and the last piece of the original one to cool that VRM

Image

there is a thermal pad between them

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now the GPU is @54° under load, the VRMs are @50°, but that small VRM still reaches 70° while playing and 125° under extreme furmark burning test, with a Tamb of 27° and all my case fan at 1200rpm (5x 12cm in an Antec p180)

Do you have a solution? Is there a cooler i can use?
I'm cutting an old NB cooler for that VRM but is not easy.
Thanx!

Posted: Thu Aug 19, 2010 2:43 am
by FJC
How are you getting the temp of that VRM?

Posted: Thu Aug 19, 2010 9:57 am
by Big Pimp Daddy
I'm also interested as to how you get that temp, in GPU-Z I only get 7 temps;
GPU Temperature
GPU Temp #1
GPU Temp #2
GPU Temp #3
VDDC Phase #1 Temperature
VDDC Phase #2 Temperature
VDDC Phase #3 Temperature

I have a very similar setup to you, reference 5850, Accelero S1, Thermalright VRM-R4 with a 120mm Nexus blowing onto it, I only have one case fan though, not five. Instead of cutting up the reference cooler I cable-tied an old RAM-sink onto the "bastardo" chip (see pic).

Image

All the temps I get in GPU-Z are fine, and have no problems with stability in Furmark or games. Are you having stability issues or are you just being cautious?

Posted: Sun Aug 22, 2010 4:05 am
by FJC
I put an AC Twin Turbo Pro on my Sapphire 5850, and used the original stock cooler metal backplate as my heatsink. It's the ONLY heatsink I'm using for the non-gpu-itself chips.

GPU-Z is reporting (after running a few days, and idle in Win7):
GPU Temp: 45C
GPU Temp1: 45.5C
GPU Temp2: 47C
GPU Temp3: 44.5C

VDDC Phase 1: 54C
VDDC Phase 2: 53C
VDDC Phase 3: 54C

After 20 min in Fallout 3, all those temps only go up a few degrees.

Posted: Thu Sep 16, 2010 6:19 am
by Darkmaniak
Hello, sorry if i'm writing my reply so late, i tried a lot of thermal pads to solve this problem, let's start answering:

@FJC and BPD:
in GPU-Z
GPU#1 is the Core
GPU#2 is MEMio
GPU#3 is arnyalo
VDDC #1,2 and 3 are the VRM "in line"

i can say this because Everest shows me the name of the sensor, so i compared the temps.

@BPD:
as i wrote, the small VRM reaches over 70° while playing and my system crashes @~95°, i tried with furmark extreme test with max AA.

after removing the original pad i used an adesive Akasa thermal pad between the VRM and the original Sapphire plate and it lower it's temps of ~10°, but it still reaches 80° during benchs.

i'm sure if i use a little cooler like your i'm going to burn it, but i'll try when i come back home

months ago a bug of MSI After Burner increased my VRM voltage to 1.6 for a week, did it damage the small VRM?

is the same problem of the old 4870 LINK

An user of another forum has the same issue that i solved by half, using a VRM-R4 for VDDC#1,2,3, but GPU#2 and 3 are still high... LINK

Posted: Thu Sep 16, 2010 10:47 am
by Big Pimp Daddy
Hmm, I don't know what to suggest then. As I said, I have the same VGA cooler as you, 120mm nexus @ 1000rpm blowing on it and one case fan. My temps for GPU#2 are FurMark-80°, gaming-60° (maximum over 3 hours). Just with that silly little RAMsink on it, and no stability problems.

Posted: Thu Sep 16, 2010 12:37 pm
by Darkmaniak
today something happened, i used an EK Water Blocks Thermal PAD between the sapphire plate and MemIO instead of Akasa AK-TT12-80 Thermal Adhesive Tape, now it's temp can't raise over 60° under Furmark fullscreen 1680*1050 AAx8 Extreme mode with a 890/1130 overclock...

i hate this card dude, i hate it Image

Posted: Mon Sep 20, 2010 2:23 am
by Parappaman
Stop using Furmark to record temperatures and live happily, that's what I did. :mrgreen:
Crysis gets my 5850 highest temps around 20° lower than Furmark or OCCT. If that game doesn't warm my card up that much, I'm pretty sure I'm fine, as no man could create a game that will do it!