AMD: Southern Islands (7*** series) Speculation/ Rumour Thread

[UniversalTruth]

And I think it is exactly the reason why you cannot adjust the voltage on those cards. Simply because the hardware is so cheap and cost effective, that it sucks.

Gigabyte is using an OnSemi NCP5395 voltage controller on their card. It does not provide software voltage control via I2C or any monitoring features.

http://www.techpowerup.com/reviews/Gigabyte/GTX_660_OC/4.html

Not sure whether they use the same or similar voltage controllers in 7950s but you can imagine.

Even nvidia is playing very dirty on their dirty expensive titanIC.

NVIDIA uses an OnSemi NCP4206 voltage controller on the Titan. We have seen this controller on many designs before. It is a cost effective solution that does not provide any I2C, so advanced monitoring is not possible. Please note how it sits on its own PCB, which means we could see different voltage controllers in the future. The GTX 680 uses a similar approach, but the variety of voltage controllers was relatively low.

http://www.techpowerup.com/reviews/NVIDIA/GeForce_GTX_Titan/4.html



Edit:
For comparison purposes:

For voltage control the card uses a CHiL CHL8228 and a CHiL 8225. We have seen both chips on recent high-end graphics cards designs. They both offer software voltage control and extensive monitoring features.

http://www.techpowerup.com/reviews/Gigabyte/HD_7970_SOC/4.html

 

[silent_guy]

Who knows what reasons are behind selecting this or the other power controller? Ripple characteristics? Dynamic behavior under wildly changing loads? Hell, let's mention it, cost?

I can't imagine that these GPUs don't have their own voltage measuring circuits. They simply may not have a need to use another external monitoring one.

Funny how topics like high amp/high precision power supplies (something I like to stay away from as far as I can because it's just so very specialized) can somehow be converted into trolling fodder.

Dirty, dirty...

 

[UniversalTruth]

Who knows what reasons are behind selecting this or the other power controller?
...
Hell, let's mention it, cost?

Yes, cost but the margin side of the cost. Which means- You will give me more and I will give you less.
Perhaps the main reason is that Gigabyte wanted to castrate and limit users from going to 7970 level of performance, thus cannibalising its sales.

 

[Kaotik]

Yes, cost but the margin side of the cost. Which means- You will give me more and I will give you less.
Perhaps the main reason is that Gigabyte wanted to castrate and limit users from going to 7970 level of performance, thus cannibalising its sales.

Except that reportedly Gigabytes 7970's and 7970GE's are using it nowadays, too.

 

[iMacmatician]

From Heise.de: "Radeon HD 7790 is the beginning of April with 896 shaders" (original).

The 7790 uses the Bonaire chip and is faster than the 650 Ti but generally ~10% slower than the 7850.

I'm guessing its core clock will be fairly high (1 GHz would put its theoretical FLOPS slightly above that of the 7850), but will have considerably less bandwidth than the 7850 does (maybe 128-bit and ~6 Gbps or 192-bit and 4.x Gbps).

In other news, Fudzilla claims the existence of working Malta cards at AMD.

 

[Babel-17]

.... they can do 1100/1700 ....

That would be a great number even for a card that had a lot of extra voltage running through it. Heat and watts start piling up fast once you hit the GHz mark.

You said 7950's, that is correct? If so, I see running at 1000/1500 as more than ample.

I have a voltage unlocked HIS 7950 fwiw.

Btw, My experience with Gigabyte is that there is one version with the voltage unlocked and one with it locked. I have a locked 6870. Beautiful card, solid components. IIRC, though "OC", for overclocked, is included in its name that only designates a mild factory overclock.

http://www.guru3d.com/articles_pages/his_radeon_hd_7950_review,1.html

They could only get it up to 1040 with no voltage modding.

http://www.hardwarecanucks.com/foru...rce-msi-hd-7950-twin-frozr-iii-review-19.html

To overclocking these cards, we used MSI’s AfterBurner tool and maxed out AMD’s PowerTune limits. Nonetheless and perhaps ironically, both of these cards overclocked to nearly identical points and neither was really all that impressive either. Rather than setting records, we’d call these results middle of the pack when it comes to HD 7950 overclocking.


Gigabyte HD 7950 WindForce 3X OC

Core: 1002MHz
Memory: 5908MHz (QDR)


MSI HD 7950 Twin Frozr III OC

Core: 998MHz
Memory: 5940MHz (QDR)

http://www.vortez.net/articles_pages/gigabyte_hd7950_windforce_review,9.html

Ok, here we go, now.

After being assured of excellent cooling (See below), we went straight in for the kill and increased the voltage to the maximum allowed (1300Mv). With this voltage we hoped for some huge overclocks and as you can see above, we were not disappointed.

1224/1503 would be nice to have but that's a result from highly stressing the card and using (relative to default) lots of juice and generating a lot of heat.

That extra 11%/22%, depending on what you settle for on your card, by way of voltage modding isn't that big a deal imo. And fwiw, 1120MHz on the core is about as high as even hard core overclockers usually can get stable with unlocked voltages and that's with great cooling and power supplies. And running a single card.

http://www.guru3d.com/articles_pages/his_radeon_7950_x_iceq_review,20.html

Hilbert got 1150MHz with this very fresh card but I still think around 1120MHz is a more representative number.

 

[UniversalTruth]

That would be a great number even for a card that had a lot of extra voltage running through it. Heat and watts start piling up fast once you hit the GHz mark.

Tahiti is usually capable to run without problems at 1200-1250 MHz, while for some extreme benching, etc people report frequencies around and over 1350 MHz.

So, it is a bit confusing what you've just typed.

 

[Babel-17]

Tahiti is usually capable to run without problems at 1200-1250 MHz, while for some extreme benching, etc people report frequencies around and over 1350 MHz.

So, it is a bit confusing what you've just typed.

Well, I own one of those cards so I have my own experience and prior to buying it I researched by browsing forums, reading reviews, and checking Newegg.

That's where I get my number of 1120MHz being a respectable overclock.

guru3d is known for pushing cards, look at what Hilbert got. Check his other HD7950 reviews.

Sure, some people only overclock one card and they have insane cooling, and they are willing to run it at the edge, so what?

psolord is running his cards in Crossfire, I don't think he's losing out much by running at 1100MHz or even 1000MHz.

Edit: psolord, is this link the one to your card? http://www.newegg.com/Product/Product.aspx?Item=N82E16814125414&Tpk=GIGABYTE GV-R795WF3-3GD

If so, it seems your card already comes with a hefty voltage. ".... it comes at a whopping 1.25v"

 

[psolord]

@BABEL

Hey man.

My 7950s are actually running at 1000/1250 from the factory but they can reach up to 1100/1700, not totally stable though. They are only sipping 1.15V according to gpuz.

I did my research before buying and I specifically asked if the cards were the 900Mhz models, because I knew some 1000Mhz models had voltage locking issues. The shop assured me they were 900Mhz models, but still I received the 1000Mhz models.

Normally I would make a fuss about it and maybe had sent them back, but they also sent me 10 games with them, which are far more than what I should get. So all in all, with the game value deducted, this is the cheapest upgrade I have done since my 5850s, so I cannot really complain.

I keep on searching on the subject though, if anything else just out of curiosity. My 7950s managed to breath down the neck of a friends 680SLI, which he paid 1000 euros for, while I actually paid 450. I am contempt with that.

Still I can't shake the thought of what could be possible with 1.25V. I will actually try to see if the card manages any lower volts, like 1.0V @800Mhz. If it does that may mean that the voltage controller does allow some user interference. If it does not, well I guess my hopes are shot.

I also tried the FZ1 bios yesterday and it does not work either.Now all my hopes rest on FX0 since it's the only one I haven't tested. I could go crazy and try some BIOS from other manufacturers though.

Does anyone know what are the rewrite limits of the EPROMs these cards use? lol

 

[Babel-17]

I'm sympathetic as I went to some extreme lengths for a while in trying to get a bios for flashing my Gigabyte Windforce HD6870. Nearly lost the card to a non-compatible rom.

Anyway, I finally got more zen about it and changed gears and just used the card as it was to smell the virtual roses.

Maybe you could just find a safe and stable clock speed for your cards and see how you like that. Needless to say, a moderate overclock is a lot easier on heat in the case and fan noise.

Btw, we have tons of memory bandwidth with these cards. My limited benching of memory overclocking suggests fast diminishing returns over stock.

We have GDDR5 memory which means that we have error correction; but we might not notice the frame rate hit from it. In other words, when overclocking the memory you might be hurting your framerates before hitting the solid line, crashing or visible glitches, that tells you, you went too far.

Anyway, you got a great deal, enjoy the cards or good luck on the exchange, whichever way you go!

 

[psolord]

Well, I almost never game with overclocked gpus and I always use vsync anyway. As long as I have 60fps steady, with good settings, I'm happy as a clam.

Overclocking/Benchmarking is a fun factor by itself though and this fun factor is the one I'm deprived of.

Still I can easily get 50% more performance over my old 570 SLI system, which is my upgrade target, so I'm cool.

Overall I feel I have gotten a good deal. The cards are great as they are.

 

[gongo]

My own research shows the max safe vcore range for Tahiti is 1.21v...the official voltage applied by AMD to the 7970GE...at that vcore most 7950/7970 can hit 1150-1180 easily.....thought the stock cooler gets loud...

If you are conservative, 1.175v works safely for 7950/7970...and you can run them at anywhere from 1130-1150mhz...depending on silicon luck....My guess why 7950 defaults to a lower 1.15v is because AMD 7950 stock cooler is much weaker than 7970....if you are on 3p cooler (like MSI TF), im certain your 7950 is safe at 1.175v...which will run you games comfortably at 1140mhz...so...just OC it!

GDDR5 OC is less depend on voltages....and more on the ram bin...i think Taihit has good MC and they should run as fast as what you ram can do...

Im also glad i got a first gen Tahiti XT just before AIBs started volt locking 'dem new ones.

my2c.

 

[sir doris]

I posted this in the PC forums but based on the last few posts maybe someone will be able to help. I've got a gen 1 7970, would I be likely to encounter any issues if X-fired with the current gen voltage locked version of the same model (Gigabyte OC)?

 

[UniversalTruth]

No, it shouldn't be likely.

 

[iMacmatician]

An OCed HD 7790 at Sweclockers gets close to a 7850.

The (OCed) clocks are 1075 MHz core and 6.4 Gbps memory.

It also looks like Bonaire has 768 SPs instead of the originally rumored 896 (unless the 7790 is a cut-down model). Maybe Hainan actually has 1536 SPs instead of 1792 then.

 

[mczak]

From the link:

This model is for price point around 1200 Euros including VAT.

Either the VAT is very high in Sweden or that's a pretty bad translation error .
I wonder what the non-OC clocks are? Typically OC models don't go that wild on memory clocks, so seeing 6.4Ghz there it's probably pretty high?
Could be pretty decent card, especially if the power consumption isn't much higher than 7770 (otherwise it will be already quite close there to 7850).

 

[iMacmatician]

Either the VAT is very high in Sweden or that's a pretty bad translation error .

I don't know Swedish, but the original text is "Modellen är avsedd för prisklassen runt 1 200 kronor inklusive moms." 1 krona is (according to Google) US$0.16 so 1200 kronor is US$188.

 

[Kaotik]

The Google translator isn't exactly perfect indeed, it for example can turn "21,5 centimeters" into "21,5 inches" and that "1200 kronor" to "1200 euros"

 

[Alexko]

I don't know Swedish, but the original text is "Modellen är avsedd för prisklassen runt 1 200 kronor inklusive moms." 1 krona is (according to Google) US$0.16 so 1200 kronor is US$188.

Yes, but apparently, for that price, an undetermined number of mothers is included.

 

[UniversalTruth]

I am not surprised at all that you mention their mothers, given also that the 7850 can be had for as low as 165-170 $.

I won't be surprised either if after some time they report that no one wants their cards...

So laughable, it's like a bad joke.