The TRUTH behind unlocking the AMD Radeon HD 6950

[compudaze]

I've read way too many “which graphics card should I buy” threads and there's one recommendation that pops up a lot. It's that you should buy a Radeon HD 6950 and unlock the extra shaders to turn it into a Radeon HD 6970. With all the hype surrounding the Radeon HD 6950's unlocking ability, I wanted to find out how much of a difference unlocking the extra shaders really makes. So began my weekend of running benchmarks and compiling the results.



AMD Radeon HD 6900 Series Specs

Here are the specs that matter for my tests:

Stock HD 6950

• Unified Shaders: 1408
• Core Clock: 800MHz
• Memory Clock: 1250MHz

Stock HD 6970

• Unified Shaders: 1536
• Core Clock: 880MHz
• Memory Clock: 1375MHz

Test Setup

I'll be using my unlocked HD 6950 2GB to simulate a HD 6970. Everything that I have read suggests it should perform identically to a real HD 6970.

Below are the specs of my test system:

• CPU: Intel Core i5 2500K @ 4.8GHz
• Motherboard: Gigabyte P67A-UD3
• Hard Disk: OCZ Agility 2 (120GB)
• Memory: Corsair Vengeance DDR3-1600 2 x 4GB (8-9-8-24 1T)
• Video Card: Sapphire AMD Radeon HD 6950 2GB
• Video Drivers: Catalyst 11.2 (8.821-110126a-112962C-ATI)
• OS: Windows 7 Professional 64-bit

Unlocking the HD 6950 2GB

I'm not going to go into detail on how to unlock the HD 6950 as there are many threads on this subject already. Instead, I'm going to explain which method I used and why.

After reading several forum posts on many different sites I decided not to flash my HD 6950 using a HD 6970 bios. There seems to be a common agreement that problems could arise from using the HD 6970 bios as the memory voltage and timings are different. I don't have any data to back this claim up, but I still chose to go with the “safer” way of modifying my original bios to unlock the additional shaders. This method allowed me to keep the cards core speed, memory speed, timings & voltages totally stock while unlocking the additional shaders. Just a note, a friend of mine used the HD 6970 bios method and hasn't had any problems with it. Your mileage may vary.



Overclocking

For my tests I also wanted to provide benchmarks for the max stable overclock I could reach on my particular card. Stable is a relative term and could mean different things for different people. It could also mean something different depending on your goal. For me, stable means rock-solid, 24/7 usage, stock-like stability.

I set out to find the max core and memory speeds I could use at the lowest voltage possible and remain 99.9999% stable. While I was able to boot at 980MHz core and run through several loops of Crysis, it wasn't stable. Sure, I could run Furmark for 24H at 950MHz, but it would crash after a few hours of real gaming. The best test I've found for stability is running the Crysis benchmark 99 times on the highest settings. If it can pass this, I'm totally satisfied.

As a result, the max stable overclock for my card was 920MHz core @ 1.175v and 1375MHz memory. No matter how much voltage I threw at it (up to 1.3v), I couldn't get stability. Is it a coincidence that the voltage required for this speed was that of a stock HD 6970? It failed at 1.165V and passed at 1.170V but I added 0.005V just to be safe. Is it another coincidence that my max memory speed was that of a stock HD 6970? Anything over 1375MHz and I lost performance. Above 1400MHz and I got artifacts. Also, unlocking the shaders didn't affect my overclock. Whether it was 1408 shaders or 1536 shaders, the max core speed remained the same.

Summary: Max stable overclock is 920MHz core @ 1.175V and 1375MHz memory

Your mileage may vary.



3DMark Vantage Test

For this test I used version 1.0.2 on the performance preset with PPU disabled. I ran the test 2 times for each setting and if the results were close, I used the average of the 2 runs. If not, I re-ran the test until I found consistent results.

3DMark Vantage seems to favor the extra shaders more than any other test. As you can see, there's a 3-4% increase clock for clock by unlocking here.



3DMark 11 Test

For this test I used version 1.0.1.0 on the performance preset. I ran the test 2 times for each setting and if the results were close, I used the average of the 2 runs. If not, I re-ran the test until I found consistent results.

3DMark 11 gives slightly more modest results. Clock for clock the extra shaders provide 2-3% more performance.



Crysis: Warhead Test

For this test I used version 1.1.1.687. Gamer Quality seems to be the most playable, but Enthusiast looks amazing and begs for Crossfire 6900's.

To me, Crysis: Warhead represents more of a real world benchmark. The gamer quality setting provides more ideal frame rates for playability. The extra shaders give a 1-3% increase here.

Cranking up the quality to Enthusiast really brought the HD 6950 to it's knees. As a result, the extra shaders only bump up performance by 2%.



Battlefield: Bad Company 2 Test

I used the latest build as of 2/21/2011. I used Fraps to benchmark the first 145 seconds after the guy says "Hey".

The extra shaders give a 1-3% increase here.



Overall Performance

I took the % numbers from all the tests and averaged them out.

Overall the extra shaders still provide 2-3% of an increase.



Closing and 2GB vs. 1GB

So... Did unlocking the shaders really make a difference? Yes and no. Yes, a 2-3% is an increase, but does that small increase really matter? I say no, not really. Especially since the more intense tests and higher core speed resulted in a slightly less performance increase. It was also interesting to find that the extra shaders do not scale with clock speed. Whether at 800MHz or 920MHz, the extra shaders still only gave a 2-3% increase. In some cases, you actually got less of an increase.

When I bought my card, the going price for the HD 6950 was $300 and the HD 6970 was $370. My results show that you get the same, if not more performance, for 81% of the cost whether you choose to unlock the card or not. With current price drops, that number drops to 75%. If you opt for the 1GB version, it drops even further to 68% (rebates not included). In my opinion, the HD 6950 1GB is the best card you can buy for the money. Sure there are faster cards, but the performance you get for what you pay is great.

Unfortunately I do not have the 1GB version to test. All the reviews I've read show that the 1GB version performs virtually identical to the 2GB version, even at 2560x1600. It's my opinion that when having 2GB of video memory matters, maybe 2-3 years from now, this card will be irrelevant and you will have already upgraded. If the 1GB was available when I purchased my HD 6950, I would have definitely got it instead.

So why buy a HD 6970? The only reason I can see is for more overclocking headroom for both core and memory.



Summary

• Locked HD 6950 overclocked to HD 6970 speeds performs within 2% of a HD 6970
• My locked HD 6950 overclocked to max performs about the same as a HD 6970
• My unlocked HD 6950 overclocked to max performs 3% better than a HD 6970

 

[crazyeyesreaper]

and yet none of this matters its simply the 5850 vs 5870 debate all over again after all 6900 or 5800 the gpu was the same just shader lock.

That said my max overclock on my 6970 is far higher then the 6950 in your system but overclocking is basically well a crap shoot some cards oc others dont, really is a game of chance, but i can hit 1000 core stable so if we compare, 40mhz jumps giving 3 %

means i gain an extra 6% from clock speed memory speed didnt do to much but 2% overall brings me 8% higher but cant deny the fact the 6950 is the better buy overall granted id still take a 2gb card over a 1 gb any day since the price difference is a $20 spot.

and i can tell you right now ive more then a few games in my possesion that use more then 1gb of Vram depending on the settings


Metro will easily hit 1400+ mb at 1920x1200
My modded oblivion install will hit 1.1-1.2gb rather easily,

2gb will be needed this year not 3 years from now, If i can take a 5 year old title and hit 1.2gb of vram usage with just shadow tweaks and a texture upgrade to 2048, Newer titles will easily surpass that,

Tessellation can hit nearly 200-300mb of usage alone and Direct Compute itself can use a large chunk of memory, i think the blur filter for metro uses a sizable chunk for instance, cant really test it for certain but if i remember right DX10 mode vs DX11 mode was a near 300-500mb jump depending on location and settings. Really i think its gonna come down to games that get released this holiday season aka Battlefield 3 and the like the new games that roll out will be hitting the 1gb barrier and then some, rather quickly.

 

[compudaze]

I added Battlefield: Bad Company 2 results and updated the overall graph.

 

[Wijkert]

Really nice work! Especially for people that like numbers more then text, I would recommend reading( ) this post. Since I have done a lot of testing (including writing everything down) I have come to the same conclusion as you have (not about the 1gb vs 2gb thing though). I am currently running my card with unlocked shaders at 880/1375 @ 1.125 volts. It is funny that the sweetspot of the memory is at 1375. A lot of people are running it at 1440 ish, but at least in my case and yours it will not result in extra performance, sometimes even less.

 

[Over_Lord]

this is a brilliant review.

this brings us to a topic of debate, should we stick to the 1408 shader HD6950 which performs identically and avoid the 1536 shader card, which consumes as much as 70-80W more power???

 

[Wijkert]

Did you monitor the temps when testing for stability? And also, what fanprofile did you use? Because 920 core seems a bit on the low side.

 

[compudaze]

Did you monitor the temps when testing for stability? And also, what fanprofile did you use? Because 920 core seems a bit on the low side.

During the Crysis test, the temps were < 80C. I have a fan profile setup so that up to 60C it's at 25%, at 80C it's at 50%, up to 100C it's at 90%. For normal usage the fan is between 40-47% keeping the GPU nice and cool.

920 was my 24/7 stable speed. I could run 99 loops of the Crysis test on max settings at 920. I couldn't do this at any higher speed regardless of voltage. I could however play black ops for a few hours at 950 core. I could even boot up in 980 core for a few benchmarks, but i don't consider those stable.

I have two sapphire cards now. Both are pretty weak overclockers it seems. My 2nd one has even worse memory. In CFX I have to run 920/1350 to pass the 99 loop crysis test.

 

[Loosenut]

Nice and well written.

Welcome to TPU!

 

[Halk]

I found your investigation very worthwhile and I enjoyed reading it. Thanks for making such detailed notes.

If I was to comment at all, it's about your value for money. You make a very good arguement that the 6950 is far better value for money than the 6970. You are, of course, correct. However you can go down the scale of graphics cards saying that at every step. Generally speaking the moderate performance mainstream cards are far better value for money than any of the high end cards. It's always been that way.

You can also easily justify buying a 6970 because it quite simply is very likely to clock further.

Personally I bought a Powercolor 6950 PCS++, I got a really good price on it (UK price approx same as a generic 1GB 6950), it comes with a custom cooler which is near silent (and if I get my way will be completely silent!). For me the price was right on this one, but it'll never be the same for everybody.

In any case though, I really do appreciate the work you've done here as it gives me a great insight into the performance of my card, and what's important when I look at custom clocking it.

 

[ctn]

Have you guys noticed that the 6950 overclocks better with a 6970 bios vs a shader unlocked 6950 bios esp on the memory. I could max out the slider on the memory on the 6970 bios but on the 6950 shader unlocked bios, it would artifact over 1375. I got around 50mhz more on the core as well compared to the 6950 shader unlocked bios.

 

[crazyeyesreaper]

thats because the 6970 bios has higher voltage herp derp, but a 6970 bios also ups memory volts which have caused more then a few 6950's ram to fail over time because the voltage was higher then it should be.

 

[LordJummy]

Have you guys noticed that the 6950 overclocks better with a 6970 bios vs a shader unlocked 6950 bios esp on the memory. I could max out the slider on the memory on the 6970 bios but on the 6950 shader unlocked bios, it would artifact over 1375. I got around 50mhz more on the core as well compared to the 6950 shader unlocked bios.

I haven't noticed that as I use a custom modded BIOS with voltage completely unlocked. However I have gone through over 4 6950's and 2 6970's to get my current setup. I cherry picked the best ones and returned the non-performers I also helped some other people out by returning the cards in perfect condition so they could buy them at an open box discount.

All of mine can OC to about 1050+ Mhz Core and very high memory clock. However as I've told lots of people - don't bother OC'ing the memory past 1400-1425Mhz. It's not going to do you any good.

 

[ctn]

thats because the 6970 bios has higher voltage herp derp, but a 6970 bios also ups memory volts which have caused more then a few 6950's ram to fail over time because the voltage was higher then it should be.

Of course I used both bios's with the same GPU voltage. Only voltage difference about the 6970 bios I used is that it has 0.1v more memory voltage than the unlocked 6950 bios.

I haven't noticed that as I use a custom modded BIOS with voltage completely unlocked. However I have gone through over 4 6950's and 2 6970's to get my current setup. I cherry picked the best ones and returned the non-performers I also helped some other people out by returning the cards in perfect condition so they could buy them at an open box discount.

All of mine can OC to about 1050+ Mhz Core and very high memory clock. However as I've told lots of people - don't bother OC'ing the memory past 1400-1425Mhz. It's not going to do you any good.

Wow 1050 core is very good. I got just shy of 1000 on the core. I also found OC on the core matters more than the memory.

I have a feeling that the 6970 bios has other tweaks in there to allow for more OC headroom.

 

[billcat479]

and i can tell you right now ive more then a few games in my possesion that use more then 1gb of Vram depending on the settings


Metro will easily hit 1400+ mb at 1920x1200
My modded oblivion install will hit 1.1-1.2gb rather easily,

2gb will be needed this year not 3 years from now, If i can take a 5 year old title and hit 1.2gb of vram usage with just shadow tweaks and a texture upgrade to 2048, Newer titles will easily surpass that,

Tessellation can hit nearly 200-300mb of usage alone and Direct Compute itself can use a large chunk of memory, i think the blur filter for metro uses a sizable chunk for instance, cant really test it for certain but if i remember right DX10 mode vs DX11 mode was a near 300-500mb jump depending on location and settings. Really i think its gonna come down to games that get released this holiday season aka Battlefield 3 and the like the new games that roll out will be hitting the 1gb barrier and then some, rather quickly.

Thanks and you have said what I've tried saying for a while now and most benchmarks have also proven out is the extra memory can make a difference. It can depend on what you run on your system but if you want to play games like the Elder Scrolls including the new one coming out soon and the fallout games the extra memory can be a nice addition and the price difference isn't all that much so I would only go with the 2GB cards. It also (I've read and can only go by what was said there) that it also follows into crossfire performance having the 2GB cards over the 1GB.
But it's all up to who ever wants what one and their reasons but all information should be noted and made very clear before anyone recommends one over the other.
Ok on that.
Now a unlocked or mod. bios 6950 beating a 6970? I'd love to know how this is possible other than a fluke GPU. and memory on the 6970 that any 6950 could out do a 6970 by 3%. That just goes right off the logic trail into area's I can not even come close to a validation. Something had to be wrong somewhere. I wouldn't even try the power color 6970 card I got, it runs stock overclocked at 940Mhz with 1450 memory and I can go up to 1Ghz no probs and 1700 memory without touching the voltage though I honestly say I didn't test it's long term stability, just played a few games and set it back but it ran cool and ran the games for a few hours, crysis 2 and fallout vegas game at max settings but res on a HD TV running at 1080P settigns.
I'm very sorry but I have to question the speed winners on those 2 cards. And like who I'm quoting off of and agree with the extra memory is used with some current games and soon the new Elder Scroll skyrm game (I think that is the title name) will be another game that will want more than the 1GB. I'd recheck your findings and do this one over again please?
I just can not agree with it. Sorry, I don't mean to sound nasty but more like a question mark on the issues other than a good way to unlock the card.

 

[de.das.dude]

i cant see them damned images!

 

[exodusprime1337]

yeah same, images are missing in mine, seemed to be linked from a foreign site.. should use techpowerup.org to alleviate this issue

 

[LordJummy]

Thanks and you have said what I've tried saying for a while now and most benchmarks have also proven out is the extra memory can make a difference. It can depend on what you run on your system but if you want to play games like the Elder Scrolls including the new one coming out soon and the fallout games the extra memory can be a nice addition and the price difference isn't all that much so I would only go with the 2GB cards. It also (I've read and can only go by what was said there) that it also follows into crossfire performance having the 2GB cards over the 1GB.
But it's all up to who ever wants what one and their reasons but all information should be noted and made very clear before anyone recommends one over the other.
Ok on that.
Now a unlocked or mod. bios 6950 beating a 6970? I'd love to know how this is possible other than a fluke GPU. and memory on the 6970 that any 6950 could out do a 6970 by 3%. That just goes right off the logic trail into area's I can not even come close to a validation. Something had to be wrong somewhere. I wouldn't even try the power color 6970 card I got, it runs stock overclocked at 940Mhz with 1450 memory and I can go up to 1Ghz no probs and 1700 memory without touching the voltage though I honestly say I didn't test it's long term stability, just played a few games and set it back but it ran cool and ran the games for a few hours, crysis 2 and fallout vegas game at max settings but res on a HD TV running at 1080P settigns.
I'm very sorry but I have to question the speed winners on those 2 cards. And like who I'm quoting off of and agree with the extra memory is used with some current games and soon the new Elder Scroll skyrm game (I think that is the title name) will be another game that will want more than the 1GB. I'd recheck your findings and do this one over again please?
I just can not agree with it. Sorry, I don't mean to sound nasty but more like a question mark on the issues other than a good way to unlock the card.

Whoa? Maybe you misunderstood the original findings. They are dead on accurate.

What is it exactly you don't agree with?

 

[crazyeyesreaper]

yea they are dead on accuract a 6950 and 6970 are the same GPU core only difference is the memory used and a 2 6pins vs 1 8pin 1 6pin

if unlocked and set to 880 core a 6950 is the exact same as a 6970 if you get a 6950 up to 930-940 core it can rival a 6970 without the extra shaders the 6950 / 6970 situation is the same as the 5850 5870 situation

 

[LordJummy]

yea they are dead on accuract a 6950 and 6970 are the same GPU core only difference is the memory used and a 2 6pins vs 1 8pin 1 6pin

if unlocked and set to 880 core a 6950 is the exact same as a 6970 if you get a 6950 up to 930-940 core it can rival a 6970 without the extra shaders the 6950 / 6970 situation is the same as the 5850 5870 situation

100% correct. I have two 6970's and a 6950 2GB unlocked, and there is no difference between them clock for clock unlocked. Actually, the 6950 overclocks higher than my 6970's lol, but it's a really special and rare bird.

 

[crazyeyesreaper]

yup its why im trying to get my hands on 2x MSI 6950 Twin Frozr III PE/ OC they have a very good unlock chance, overclock well and have good cooling, to replace my 2x Dead 6970s no point buying the 6970 when if your smart and know what to look for you can get the same thing for $70-90 cheaper

 

[eidairaman1]

reason for top end is cuz u know they will work fine at the settings they are intended for

 

[CentaurAOA]

Hi to all< would anyone do the kind favor of emailing me a copy of the original bios for
the sapphire HD6950 Dirt 3 edition card please????????????????

 

[95Viper]

Hi to all< would anyone do the kind favor of emailing me a copy of the original bios for
the sapphire HD6950 Dirt 3 edition card please????????????????

Well, first, welcome to TPU.
Second, sorry, I don't have a bios for that card... did you check the bios database real good?

Not trying to get on you or anything, but you should not hi-jack someone elses thread for a new question.
You should have started your own thread, you would probably get more look sees and answers.

You might wanna delete the post and start a thread or ask a MOD for help.
They would, probably, be more than glad to help you.

 

[TheoneandonlyMrK]

Unlocking the HD 6950 2GB

I'm not going to go into detail on how to unlock the HD 6950 as there are many threads on this subject already. Instead, I'm going to explain which method I used and why.

After reading several forum posts on many different sites I decided not to flash my HD 6950 using a HD 6970 bios. There seems to be a common agreement that problems could arise from using the HD 6970 bios as the memory voltage and timings are different. I don't have any data to back this claim up, but I still chose to go with the %u201Csafer%u201D way of modifying my original bios to unlock the additional shaders. This method allowed me to keep the cards core speed, memory speed, timings & voltages totally stock while unlocking the additional shaders. Just a note, a friend of mine used the HD 6970 bios method and hasn't had any problems with it. Your mileage may vary.

afaik in most applications your card will still be seen as a 6950 and the application will apply a spec accordingly and regardless of changes ie possibly not optimised for more shaders you can change or hide the vendor id etc tho?

 

[eidairaman1]

afaik in most applications your card will still be seen as a 6950 and the application will apply a spec accordingly and regardless of changes ie possibly not optimised for more shaders you can change or hide the vendor id etc tho?

cuz if u dont change the device ID in the BIOS/Firmware of the card...