6950 Stops OC at 885/1380 - Why?

C

Constantine769

Weaksauce
Joined
Nov 16, 2006
Messages
89
I flashed my Sapphire 6950 with a modded 6950 bios and OC'd to 885/1380.

Whenever I push it higher, I get software errors from 3DMark11 and Furmark crashes or freezes.

My temps never go over 65C even at 100% load at 885/1380, so I would imagine there wouldn't be much of an increase in temps if I put it at 900/1395.

It ran stable at 900/1395 until I ran benchmarks and stability tests.

Anyone know why?

Thanks
 
Because the parts just can't handle the frequency. You could always try bumping up the core voltage. Also could be because the RAM is only rated for 5GHz (1250 x 4) and you're running it at 5.52Ghz. OC's aren't limited by just temps.
 
Ah, k. I'll try that.

What is the "safe" limit of for the voltage of the GPU and at what temperature can I safely max the card with 100% usage?

I want to get more bang for my buck but I don't want to burn my buck at the same time you know? hehe

Thanks
 
I'm running into a problem with afterburner.

Even though I unlocked voltage control in the settings, I still can't adjust the voltage. I even tried editing the cfg file but no dice.

Any ideas?

Thanks
 
What is the "safe" limit of for the voltage of the GPU and at what temperature can I safely max the card with 100% usage?
Click to expand...

Up to 1.25V should be a good baseline. Just keep it cool.

Even though I unlocked voltage control in the settings, I still can't adjust the voltage. I even tried editing the cfg file but no dice.

Any ideas?
Click to expand...

You need to be using Afterburner beta 7.
 
That might just be the max of that card, you have to remember that over clocking isn't a 100% deal, you can not buy an given card and know or think that it will unlock and over clock as good as the next

Get crossfire and it will become even harder for you


With one 5850 I can clock it to 1070/1300 while the other is only able to do 1060/1250(not because of temps or voltages or any other factors other than the fact the card will not go higher)... so guess what, I have to settle for 1060/1250 for both them when they are crossfired. which isn't anything to complain about it is just what I am able to get out the card.
 
If you are getting the "Access Denied" when you change the config file, be sure to copy that config file to another location, like your desktop. I actually make two copies of it, one for backup. So you make the changes of the config file on your desktop, save it and then copy the file to Afterburner folder. Note: You need to close out Afterburner program first before you make changes to the config file. Ok something else you might need to change in config file where is says:

EnableUnofficialOverclocking = 0 (change that to a 1)

Then just under that change you need to put this:

I confirm that I am aware of unofficial overclocking limitations and fully understand that MSI will not provide me any support on it
 
Flash the unlock only bios on the card and find the highest stable core clock (leave memory alone) while raising the voltage of the gpu and keeping temps in check. It's my findings that pushing the core alone will get you a better overclock than trying to move both the core and the memory at the same time. Once you've established a stable core frequency start moving the memory up little by little until you lose stability again. Once you find that spot on the ram where you lose stability, scale back 5-10mhz and call it a day. Flash the new bios with that new found core and memory frequency and your good to go.

Oh and to throw this in there. The 6970 bios has a higher memory voltage and can help a bit with the memory if your willing to give it a try. Not all cards can handle that bios due to the timings and voltage on the vram, luckily my cards can. If you are not happy with your memory overclock you can try that.
 
The 6970 bios has a higher memory voltage and can help a bit with the memory if your willing to give it a try.
Click to expand...

That's not true. Both memory chips are rated at 1.5V, just the 6950s are rated for 5GHz and the 6970's is rated for 6GHz. Here's the memory chips page. The 6950 uses the T2C and the 6970 uses the R0C.
 
FaRKle0079 said:
That's not true. Both memory chips are rated at 1.5V, just the 6950s are rated for 5GHz and the 6970's is rated for 6GHz. Here's the memory chips page. The 6950 uses the T2C and the 6970 uses the R0C.
Click to expand...

What the chips are rated at and what voltage is assigned in the vga bios are 2 different things. In the link you provided it says 1.5/1.35. TBH though, I haven't seen proof either way. I haven't seen proof the voltage is different or not different. I can just say from the countless threads on overclocking that the reason many people believe the voltage is different is due to differences in power draw and temp that happen when you use the 6970 bios vs the 6950 unlock only shader bios with the 6970 core voltage. There is a timing difference too on the chips.
 
Lord_Exodia said:
Flash the unlock only bios on the card and find the highest stable core clock (leave memory alone) while raising the voltage of the gpu and keeping temps in check. It's my findings that pushing the core alone will get you a better overclock than trying to move both the core and the memory at the same time. Once you've established a stable core frequency start moving the memory up little by little until you lose stability again. Once you find that spot on the ram where you lose stability, scale back 5-10mhz and call it a day. Flash the new bios with that new found core and memory frequency and your good to go.

Oh and to throw this in there. The 6970 bios has a higher memory voltage and can help a bit with the memory if your willing to give it a try. Not all cards can handle that bios due to the timings and voltage on the vram, luckily my cards can. If you are not happy with your memory overclock you can try that.
Click to expand...

That's a really good tip. Thank you. I will try that after I OC my CPU. What is the safe Idle/Max temp for the 6950? (Without running the fan on 100%, only on Auto)

I don't want to flash the 6970 Bios on my card due to the fact that I've read one too many people damaging their card even after they flashing it back. I don't want to risk it.

The highest I have reached without ramping up the voltage is 860/1345. My card idles at 50-52C. I feel that that is somewhat high already so I think I will stop there. My fan is on auto and it is way too loud whenever it gets passed 75-80%.

It was stable at 885/1395 for sometime but then it would randomly crash and freeze my computer from time to time so I decided to bump it down to safer levels and hasn't crashed or frozen since.

I am getting about P5350 in 3DMark11 which isn't bad and is higher than a majority of the systems listed with the same setup.

My i7-950 isn't overclocked yet. I am waiting for my Antec Kuhler H20 620 to arrive soon then overclock it to around 4GHz-4.2GHz. That will hopefully bump my total score up to almost P6,000 or hopefully at least break it.

If it doesn't then I will try the voltage bump and OC the GPU some more.

Thank you for the suggestions and help.

Well appreciated.
 
In the link you provided it says 1.5/1.35.
Click to expand...

If you read the PDF the 1.35V is for one of the other chips listed on that page. Both the T2C and R0C are 1.5V chips. And really, do you think that AMD is going to play around with memory voltages when they're running the chips at max rated frequency (5GHz for the T2C). Assuming they did play with memory voltages, if anything they'd be running the 6970's R0C chips at lower than 1.5V since it's RAM frequency is only 5.5GHz while the chips are rated for 6GHz. This goes against the common perception that "the 6970's RAM runs at a higher voltage." Also, the timings have nothing to do with voltages here.
 
Atleast your ram can go over 1325, mine doesn't go pass that.
The core can reach 950 though. Currently running it at 925.
 
WorldExclusive said:
Atleast your ram can go over 1325, mine doesn't go pass that.
The core can reach 950 though. Currently running it at 925.
Click to expand...

Are you running at stock voltages and temps (idle/max)? GPU and Ram clocks?

I'm not sure what the max frequency of my GPU and Ram is yet. I need to play with it by increasing them one at a time. Just like Lord_Exodia suggested.

I just have to figure out how to unlock the voltage controls. I've unlocked the GPU and Mem clock controls as you can see I am over the 840/1325 Overdrive limit.

The shaders are also already unlocked.

The odd thing is, at 890/1400, my computer only freezes or crashes when I am playing games. When I do a stability tests such as MSI Kombustor and Furmark, it doesn't crash even after running it for a straight hour. All this at stock voltages.
 
You must log in or register to reply here.
Back
Top