The wierd 6790!!!!!!!!!

[kaspro]

Hi, i know that amd is replacing the 5770 with the 6790 vga card which i think its useless, first its just around 10 or 15$ less than 6850 so i'd rather get the 6850 + it really didnt show great effect going to 256bit from 128bit in the 5770 as i though it would really make a big difference.........so i really dont see the point!!!

 

[4745454b]

Both sides have released cards that don't really have a point. The last two gens have seemed to have stalled a bit when it comes to increasing performance. Possibly due to at first the issues 40nm had, then the forced continued use of 40nm because the next node had been delayed. Once we get 28nm things should be different.

 

[iam2thecrowe]

can anyone explain why the 6790 uses more power under load than a 6850? i know its a cut back version of the same chip, but why would it use more power? Where is this power going?

 

[gracefully]

^I'm wondering about that too. How come a lower performance product consumes more power? It goes against logic.

 

[4745454b]

Because the PCB is the 6870s, not the 6850s. They use different VRM and other parts, which need a higher voltage, so the card as a whole uses more power. They did the same thing with the 5830, which used the 5870s PCB and not the 5850s.

 

[gracefully]

I see. So they simply made the 6790 as an outlet for 6870s that cannot perform like one. They just shut off a few components, labeled it a 6790, and called it a day.

 

[jryan388]

So it really should be a 6830?

 

[4745454b]

I guess gracefully. Its also possible that they have more 6870 PCBs laying around because the 6850 is selling better. The chips themselves, 6790, 6850, and 6870 are all the same chips less whatever is disabled to make the lower cards. Calling it a 6830 might have made more sense. Same chip, might as well use the same naming scheme right? I have no clue why they called it a 67xx.

 

[gracefully]

^
^
Yeah, I think it should've been a 6830, but then you'd be able to Hybrid-Crossfire it with the other 6800 series, and AMD doesn't want that.

AMD said that the 6790's deactivated parts were physically disabled, which is probably why they decided it belonged to a different series, because products in the same series have functional units which are only logically disabled.

 

[ChromeTusk]

So it really should be a 6830?

Correct me if I am wrong, but wasn't the 5830 a failure? Maybe the marketing department thought the GPU would sell better under a different name.

 

[iam2thecrowe]

yeah the 5830 was a power hungry flop, they should have learned their lesson there. People dont want a card that uses more power to produce less performance. People buying these lower end cards often do so because they have a lower end PSU. So this card will be a huge flop. Why the hell didnt AMD see this coming? they should ditch this poor excuse for a card and just bring in a tweaked/overclocked 5770 and re-badge it as a 6770.

 

[4745454b]

I'm not sure there are any tweaks for the 5770. There are no blocks to enable, so all that could be done is perhaps a process tweak to enable higher clock speeds. Its far easier to cut down a different chip to enable something faster. The only move I questioned was the use of the 6870s board, as that increased power consumption. Perhaps a nice aftermarket one based on the 6850 will show what it could do if they did things right.

 

[Timop]

6790s make perfect financial sense, literally salvaging "useless" failing barts dies; literally they could price it $100 and make cash, just then stock would be pretty limited.

The reason its named 6790 is probably because of the 5830, and the lack of a 6700 series. AMD has been physically fusing off shader for ages, eg 6850.

 

[gracefully]

So... the 6790 is the most senior model of the 6700 series, making room for a "true" 6770 and 6750 down the line.

Yeah, I guess it's just to prevent some association with the flop that was the 5830. Same thing, new name.

 

[Timop]

So... the 6790 is the most senior model of the 6700 series, making room for a "true" 6770 and 6750 down the line.

Yeah, I guess it's just to prevent some association with the flop that was the 5830. Same thing, new name.

AFAIK there will be no "true" 6770, just 5770 rebrand (maybe +OC for retail) and the same for 6750 as well, Caicos simply isnt powerful enough at 480SP. But that should be the right idea.

 

[iam2thecrowe]

I'm not sure there are any tweaks for the 5770. There are no blocks to enable, so all that could be done is perhaps a process tweak to enable higher clock speeds. Its far easier to cut down a different chip to enable something faster..

i didnt mean it like that. i mean the 5770 has been a good card since it was released and people are still buying it. If they just take that basic design, fix up the crossfire scaling to the 6xxx series and bump up clock speeds, maybe add 256 bit memory, and call it a 6770, that would be a good mid range card.

 

[EXT64]

Notice that the 6790 has a higher core clock than the 6850 to make up for its loss of cores. Couple that with the fact that these are probably not the best chips (perhaps higher voltage, leakage?) and you get the higher power consumption. I think that the 5830 was the same way - consuming way more power than it performed at (didn't the 5830 use more power than the 5850 even?!?)

 

[Timop]

i didnt mean it like that. i mean the 5770 has been a good card since it was released and people are still buying it. If they just take that basic design, fix up the crossfire scaling to the 6xxx series and bump up clock speeds, maybe add 256 bit memory, and call it a 6770, that would be a good mid range card.

That qualifies as a major redesign. adding memory channels and improve crossfire scaling on the hardware level needs fresh new silicon. Even the "redesigned GF110 Fermis" was not much more than a respin.

^^The higher power consumption is most likely leaky inferior plus the higher clocks, its probably the same reason why the 6950 1GB uses more power, as they have to cut costs somewhere and the lower binned chips are the ideal choice.^^

 

[4745454b]

I agree with timop. You can't just add in memory channels to increase the bus. And if its already near the top end of the clock speed, you can't just clock it higher. (the GTS450 has a high overclock headroom, I haven't heard the same about the 5770.) The question then becomes do you attempt to remake the 5770 into a 256bit GPU with extra stuff in it, or just take the reject 6850/6870 and cut some more out? Obviously the easy, cheaper, and fastest way is the one we got.