After some googling I found out that 7970s are shipping with 3 different voltages, namely 1.05, 1.112, 1.170 with the latter being the most common. According to MSI Afterburner, mine is at 1.05 voltage. Am I right to think that since 1.170 volts is the most common, I might as well just up the voltage to that, overclock it to my heart's content, as if I never even tweaked the voltage on my card? Would it be safe to go even further, as if 1.170 was stock voltage?
They come with different voltages because they are assured to be stable at the required stock clocks at those specific voltages. Each card is different and has difference tolerance to voltage. The ones with high stock voltage are low ASIC cards. They respond really well to higher voltages and they OC well as you up the voltage. In return, they consume more power and run hotter. The ones with low stock voltage are high ASIC cards. They overclock really well at stock voltages, but do not take too well to voltage increases. You'll find they hit a wall at a certain clock and voltage where no additional voltage can make the card stable. Low ASIC cards would generally overclock / overvolt beyond that wall PROVIDED YOU PROVIDE THEM WITH BETTER COOLING! This means that, generally, on air, with moderate voltages, high ASIC cards OC better than low ASIC cards. This also means that, generally, on water, phase-change, and liquid Nitrogen, low ASIC cards OC better than high ASIC cards. These voltages all fall within any 7970's voltage tolerance levels. All high ASIC cards I've seen easily take 1.17V, of course. But this isn't a general rule you can apply everywhere. This targets your question by providing an example: Gigabyte 7950s recently came with a BIOS that ran the cards at 1000MHz stock clocks and 1.25V stock voltage. Gigabyte cards, however, seem to be low ASIC, so they can take those voltages and respond really well to them. You'll see them soar in OCing. There's even a thread about this very topic: http://forums.guru3d.com/showthread.php?t=374287 However, high ASIC cards may not tolerate, or respond to, these voltages (1.25V). A friend's MSI 7950, 90% ASIC, reached 1100MHz @1.1V. Up the clock to 1125MHz, and not even 1.2V could make it stable. The highest stable OC, 1100MHz, was running at around 70C. The unstable OC, 1125MHz, was running at 86C! Of course, this is with stress testing, but I believe this is the way to OC your card, as with certain games, you'll realize your OC is unstable, and those games are, by themselves, as close to a stress test as you can get with a game. This means that in general, with that voltage of 1175mV, yes, you can take your card there even if it has high ASIC although this is STILL considered overvolting (and comes with all the risks and tradeoffs of overvolting), as the card's stock voltage is still 1.0x V. On the other hand, a low ASIC card that ships with a higher voltage may not be stable at stock clocks with a low voltage of 1.0x V that ships with high ASIC cards. Two different cards, two different stock voltages, two different scenarios. Neither runs "stock" at the other's voltage. Hope this answers your question.
Very helpful and thorough explanation, thanks a lot. I've been playing with it and it would seem I'll hit at wall at 1125 or close to that. I'm still only at 1.112v, but that's only 75Hz more for a 0.062 increase in voltage (stable at 1050 stock voltage), and that's still unstable. Either way, I've already made a special edition card out of a standard one, I'm happy enough with that.
Asic? I'm confused by the reference to "high ASIC" and "low ASIC". As I understand it, ASIC is an acronym for Application Specific Integrated Circuit, referring to a particular type of IC. GPUs are most definitely ASICs, as they're designed to do very specific types of computation. What does "high" and "low" refer to here (or am I confusing some other term with the typical ASIC acronym)?
Excellent answer and spot on. I had a golden 7970 that had a stock voltage of 1.12v and would bench at 1340 core on air.
84,5 asis org bios 1.17v power safe 20% 1000/1350 ref 7970 new mode bios 1200/1650 1.2v power safe 50% max clock ? not test whit 1.2v but max clock whit 1.3v it is 1400/1845 I use watercooling max temp 40c load
Yes they were. A testament to how good they were is that they still offer good performance even today, that 384 bus bus and 3gb of video memory gave the card decent future proofing.
I have a 7950 TF3 which is on a 7970 PCB (1 * 6 & 1 * 8) and my ASIC is 92.8%. Here are my 3 overclock settings: Stock overclock = 1010/1575 - .994mv (Stock) Core Voltage - Stock Memory Votage - No Power Limit %+ 24/7 overclock = 1110/1600 - 1069mv Core Voltage - Stock Memory Voltage - Power Limit 20%+ Stress Test/Benching overclock = 1150/1650 - 1100mv Core Voltage - Stock Memory Voltage - Power Limit 20%+ I have tried to shoot higher (1200+) but it either becomes too hot because of Voltage, or the Fan gets too loud for my delicate little ears.
Thats pretty much top quality overclock. But yeah my 7950's asic quality is only a 62.5%. I'm sitting stable @ 1160/1500mhz but with 1.250v.
Why thank you, I pride myself on my anal overclocking practices (Highest Possible Speed VS Lowest Possible Volts/Temps).
Thanks! Its netted me a high of 7699 in FireStrike (did have a screenshot but now appears to have disappeared). My 7950 has been an absolute soldier since Day 1. Only gripe is it can get a little loud (55% Fan Speed+ becomes quite audible), but all I do is turn my Music/Games volume up and the problem goes away! Edit: Here she is! In all her naked pre paste glory!
yeah I have an 85.8%er here. As far as the future proofing I seen no reason to upgrade yet. I still feel like I have a strong card 1080p gaming.