7950 v 7970

Bepolite

I wonder if anyone can explain this.

Sapphire ship the 7950 running at under 1 volt core, where as I've seen 7970s as high as 1.2V core. Am I mis reading something? My understanding was these were identical chips, just different bins, with some of the shaders turned off. How can the 7950 (that I have anyway) and a 7970 be such different voltages? If I put 1.2v throun my 7950 it's fry it!

I suppose what I'm asking, is there a hobble going on here?

Sarz91

Bepolite wrote: »

I wonder if anyone can explain this.

Sapphire ship the 7950 running at under 1 volt core, where as I've seen 7970s as high as 1.2V core. Am I mis reading something? My understanding was these were identical chips, just different bins, with some of the shaders turned off. How can the 7950 (that I have anyway) and a 7970 be such different voltages? If I put 1.2v throun my 7950 it's fry it!

I suppose what I'm asking, is there a hobble going on here?

Shouldn't do. I've my 7950 at 1250.

Bepolite

Sarz91 wrote: »

Shouldn't do. I've my 7950 at 1250.

I thinks it's something funky with thew sapphire cards, certain ones like the 950Mhz edition (the one I have) are under-volted. Perhaps the cooling system is a bit crap? (Dual X)

I'm running at 1050mV 1100Mhz at 74C stable fans at 80%+

Bepolite

90.3% ASIC BTW not sure if thats good or not.

Gumbi

No. It is directly correlated to ASIC as far as my research goes. higher ASIC means less "leakage" thus allowing much lower voltages to keep give clock speeds stable.

My 950mhz edition would asplode if I put 1.2+ volt into it, whereas many reference cards run 1.25 at stock. It is not something I understand fully.

Also, higher ASIC tends to mean higher potential overclock, but it may be harder to obtain due to heat, but put both under water and my bet would be on high scoring ASIC cards to score higher most of the time.

It's not to do with the cooling either, the DualX is a decent cooler. It cools 7970s at 1.2v FFS :P

A moderate clock speed profile of mine is 1043mv for 1100mhz core, I think I can go as low as 1037 (voltage applied in 6mv increments), but I'm not 100% sure on that. My ASIC is similarly high at 90.1%. We both have HUGE core clock speed headroom due to very low voltages, meaning if we put both our cards under water to tame the VRMs and core we would be looking at gaming clock speeds of 1350 easily, which is preposterous :P

By the way, will you do me a favour and tell me your stock voltage at 950mhz?

Bepolite

1012mV.

I got let down on on some water cooling bits and bobs annoyingly! I think it's going to have to stay on air for the time being.

Does anyone know of a external water cooling solution. I'm thinking a tower radiator with built in pump and reservoir.

Gumbi

KK 1012mv same as mine, and almost identical ASIC score too. You can do 1600mhz on memory without modifying the mem voltage (you need a modded version of Trixx to do this). You have Hynix then. If you decide to go water you won't regret it with that card. You'll be able to cool 1.2+ volts. You can do 1200mhz at ~1112mv (that's what it's like for me, more like 1210mhz actually), think of what you can do with another 0.1v

Bepolite

Gumbi wrote: »

KK 1012mv same as mine, and almost identical ASIC score too. You can do 1600mhz on memory without modifying the mem voltage (you need a modded version of Trixx to do this). You have Hynix then. If you decide to go water you won't regret it with that card. You'll be able to cool 1.2+ volts. You can do 1200mhz at ~1112mv (that's what it's like for me, more like 1210mhz actually), think of what you can do with another 0.1v

I'm doing 1600Mhz on standard Trixx - how do I get a modded version? Bit reluctant to let this one be at the mercy of the google fairy

Are you running at 1112mv on air? I'm hitting 74C (at 74% fan now) bit worried about pushing it any further.

Thanks for all the info btw!

EDIT: Had to try it :P I'm seeing run away temps at 1112mv - I set myself a limit of 80C where my fans jam themselves to 100% over the 80-85C. 80C is my fail condition. Call me a pussy but I'm poor at the moment

Gumbi

I have an Acclero Xtreme mounted, so core temps are EZ for me . The VRMs not so great though, and get to 85 degrees at that voltage. Which is fine, by the way.

Bepolite

Gumbi wrote: »

I have an Acclero Xtreme mounted, so core temps are EZ for me . The VRMs not so great though, and get to 85 degrees at that voltage. Which is fine, by the way.

Nice. just had a google of that. I think I'm gonna check I'm stable on 1100/1600 before I do anything else. Had to up the voltage to 1050mv today as I was getting artifacts in Fallout:NV.

I'll keep an eye out for that tower thing I want, hope someone makes one.

Gumbi

Bepolite wrote: »

Nice. just had a google of that. I think I'm gonna check I'm stable on 1100/1600 before I do anything else. Had to up the voltage to 1050mv today as I was getting artifacts in Fallout:NV.

I'll keep an eye out for that tower thing I want, hope someone makes one.

It's really over priced in some places, I paid 40 euro for it on Hardwareversand. I wouldn't spend more than that on it though ,even if it is priced double that in some places.

BloodBath

How's your case airflow? I have had my Sapphire 7970 Dual-X at 1200/1800. Temps were maxing at 76c with 56% fan speed. My case airflow is really good though. I have 2 x 200mm intakes and a 200mm and 140mm exhaust.

Back down to 1150/1650 for everyday use.

I'm running at 1050mV 1100Mhz at 74C stable fans at 80%+

That's high temps for that voltage and clock speed. I'd say your case airflow is the thing letting you down.

Bepolite

BloodBath wrote: »

How's your case airflow? I have had my Sapphire 7970 Dual-X at 1200/1800. Temps were maxing at 76c with 56% fan speed. My case airflow is really good though. I have 2 x 200mm intakes and a 200mm and 140mm exhaust.

Back down to 1150/1650 for everyday use.



That's high temps for that voltage and clock speed. I'd say your case airflow is the thing letting you down.

Have a look in the pics thread and see what you think. I'm pretty sure air flow isnt an issue, but I could be wrong. My rig.

The 200mm isn't on the fan controller its coming off the MB header, could be spinning a bit slow, I'm going to sort than in the next few days. It's set up as 200 and 120mm intake and 3x 120mm exhaust.

BloodBath

Ah those cases look great but aren't the best cooling wise despite the big ass front intake. It still should probably be better than it is. Do you leave the side off all the time or do you put the windowed door back on?

Maybe the paste was poorly applied or the contact on the gpu isn't as good as it should be. Lot's of minor things can add up to big differences.

Bepolite

It's a full acrylic side panel (it's on in the top pic) I actually get slightly better temps with it off. I've reapplied the thermal past and it's better than it was. The heatsink assembly is pretty rough though, I think I might have just got a Friday afternoon assembly.

BloodBath

Is it possible to add another intake fan to the bottom of the case? Even if it means moving the HDD cage behind the front intake it might improve temps. Not sure if that's possible but just an idea.