Which is the maximum safe temperature for vga memory chips?

mits · Post by **mits** » Mon Dec 18, 2006 12:06 am

Hi all,
i'm asking this question because i had an Ati silencer 5 installed on my X850XT constantly at 7Volt and although the GPU temp never exceeded 62C under load the mem temp reached as high as 55C under load. After sometime (1 year) the card started to create artifacts during gaming, could that be due to mem overheating?
So i reinstalled the original cooler. To my surprise the mem temp dropped 8-9C under load while of course the GPU temp climped up to 80+C. Is that probably a problem of the Ati sliencer since it uses thick thermal pads to have good contact with the mem chips?
Has anybody used a zalman VF-700 or VF-900 with an Ati X850XT and what gpu and mem temps has achieved?

Any info is appreciated.

Bluefront · Post by **Bluefront** » Mon Dec 18, 2006 2:37 am

Your current display problems could have been caused by over-heating....but it's only a possibility. I have not heard of any vga memory problem caused by switching to a Zalman cooler. Just how are you determining the memory temperature?

My system uses a P4-3.4 NW, and until recently I was using an ATI X800 XT AIW........I installed a VF700 on the card, running the fan at a fixed voltage (about 6-7v). I just adjusted the voltage to the "sweet spot" for the fan. It was fairly quiet in my case.

The temp of the card dropped dramatically (using ATI Tool to measure). I never checked the vga memory specifically, but the chips themselves felt fairly cool. I put some small heatsinks on the chips anyway. My card idled about 40C......maxed about 65C. If I increased the fan speed, the temp got lower.

I also made a duct for the card.....some of the air was blown upward, some was blown at the rear opened pci slot cover. Tell you what though....trying to compare temperatures between different systems is difficult because of the many differing factors......

mits · Post by **mits** » Mon Dec 18, 2006 4:01 am

Hi Bluefront,
i "measure" the mem temperature by using the atitool, the second reading that is labeled as "Gpu environment temperature" in the settings -> temperature monitoring. Actually i have tested this temp reading against the reading i get from Asus's tool smartdoctor from a 9600xt and it is the same. So i believe that this reading is the mem temperature for the x850xt as well. Also the aluminum backplate on the ati silencer (that covers the mem chips) felt fairly hot to the touch. I believe that something must have gone wrong with the mem chips (either from heat or just defective chips) because the artifacts disappear when the mem clock is lowered to 480-485MHz (default is 540).

andyb · Post by **andyb** » Mon Dec 18, 2006 5:14 am

Chips of any kind can go pear-shaped after prolonged usage at higher than rated speeds and/or voltages.

There is a very real chance that your RAM is now no longer usabale at the higher speeds, and if it works at the default speeds just fine, I would suggest using the card at the default RAM speeds.

Likewise this might be the GPU going wrong if that is overclocked as well, artifacts are not always the RAM.

Many people will say that they have never had any problems with long-term overclocking, all I can say is that they are lucky, I have personally experienced problems that I can only explain by long-term overclocking. All of the problems vanished when I reduced the clock to factory defaults.

In short I dont believe that this is a heat issue.

Andy

mits · Post by **mits** » Mon Dec 18, 2006 12:47 pm

[Andyb]
i might not have been clear enough, but the card has never been overclocked and the default speeds of the card are Gpu:520 and mem:540(x2). I realized that the artifacts are due to mem problem because i underclocked both mem and gpu and gradually i started to increase their frequency. With whatever gpu frequency <= 520 and mem>=485 (default is 540) i have artifacts. Even with gpu > 520 but mem at 480 the image is artifact free.