AMD: R7xx Speculation

[sireric]

So about an hour and a half left or so huh? This anticipation is killin me

Gotta get some popcorn!

 

[Megadrive1988]

FYI. This is the "96 Shader" chip Orton talked about some time ago. Things change.

Wait, what is the "96 Shader" chip Orton talked about awhile ago? I'm confused. You mean the 480 SP RV770 that turned out to be a ruse?

 

[Silent_Buddha]

Argh time flies when you get older, but right now it's not flying fast enough.

 

[3dcgi]

Not sure I follow this. Why would it be pad limited if it's larger than rv670? Shouldn't it have only a slightly larger pad count?

GDDR5. And Rys said it was pad limited with 8 SIMDs so it was smaller.

 

[Farhan]

Wait, what is the "96 Shader" chip Orton talked about awhile ago? I'm confused. You mean the 480 SP RV770 that turned out to be a ruse?

maybe it was just VERY pad limited...

 

[silent_guy]

• Chip was pad limited in the beginning***, so the last couple of SIMDs are value adds that weren't originally planned for. Explains the first point a little bit.

That's really puzzling. The way thing normally go, final area is always larger than initially estimated. I've never seen it otherwise...

This really points to some serious design methodology changes along the way.

 

[Pete]

Wait, what is the "96 Shader" chip Orton talked about awhile ago? I'm confused. You mean the 480 SP RV770 that turned out to be a ruse?

I think it's from here (discussed here and later here). So, back in R600 speculation. "Some" time ago is right.

 

[fellix]

FP16 filtering is half speed, and the samplers are limited by available interpolators (only 32 texcoords/clk) when processing INT8 at full speed

Now, I know what I want to see *fixed* in the next full/half node refresh of the architecture!

 

[Jaaanosik]

AT is up here.

It seems HD4870 tops GTX260 here as well.
In many cases it's as good as GTX280 at 16x10.

 

[Silent_Buddha]

Anandtech review up...

http://www.anandtech.com/video/showdoc.aspx?i=3341

Regards
SB

 

[Dave Baumann]

Wait, what is the "96 Shader" chip Orton talked about awhile ago? I'm confused. You mean the 480 SP RV770 that turned out to be a ruse?

That's really puzzling. The way thing normally go, final area is always larger than initially estimated. I've never seen it otherwise...

This really points to some serious design methodology changes along the way.

Starting point was the cost target. The initial specification was 150% over R600, however the engineering focus was area optimization, so once they got underway the efficiency gains mean we could be 8 SIMD's (200% R600); a little while later, due to further gains, GDDR5 and a couple of other things, we were pad limited at 8 again, so the additional 2 SIMD's were lobbed in. And I'm not complaining about that!

 

[Rangers]

Great and AT is currently down for me :0

And I dont see any other reviews yet..

 

[AlphaWolf]

Great and AT is currently down for me :0

And I dont see any other reviews yet..

hexus has a review up also.

AT is getting hammered, all of you stop hitting F5 dammit!

 

[randomhack]

Got this list from tweaktown :
http://www.hothardware.com/articles/ATI_Radeon_HD_4850_and_4870_RV770_Has_Arrived
http://www.hexus.net/content/item.php?item=13972
http://www.hardwarecanucks.com/foru...radeon-hd4870-512mb-graphics-card-review.html
http://www.anandtech.com/video/showdoc.aspx?i=3341

 

[Pete]

FYI, the 4870 review thread is here.

Anyway, if this thread stays open until Rys publishes B3D's piece, I'd like to know what's up with RV770's idle draw. People here who seem to be in the know have said it's the drivers, but I haven't seen it mentioned specifically in any p/review, not even the new ones, so has AMD officially briefed ppl about it?

 

[AlphaWolf]

FYI, the 4870 review thread is here.

Anyway, if this thread stays open until Rys publishes B3D's piece, I'd like to know what's up with RV770's idle draw. People here who seem to be in the know have said it's the drivers, but I haven't seen it mentioned specifically in any p/review, not even the new ones, so has AMD officially briefed ppl about it?

I think people are basing it on the idle speed of the rv770, its idling at 500mhz instead of the 300 that the rv670 idles at. I don't know that it's a bug.

 

[Psycho]

Anyway, if this thread stays open until Rys publishes B3D's piece, I'd like to know what's up with RV770's idle draw.

Please let it stay a little longer if needed, until it reaches 4850/70 posts, it's so close now

 

[ZerazaX]

Can't wait for the architecture analysis... looks like ATI really did a TON here

 

[ZerazaX]

Rage3d has their architecture overview up:

http://www.rage3d.com/reviews/video/atirv770/architecture/

That shot of all the die on a wafer is just pure sex... beautiful!

 

[Shadowmage]

Starting point was the cost target. The initial specification was 150% over R600, however the engineering focus was area optimization, so once they got underway the efficiency gains mean we could be 8 SIMD's (200% R600); a little while later, due to further gains, GDDR5 and a couple of other things, we were pad limited at 8 again, so the additional 2 SIMD's were lobbed in. And I'm not complaining about that!

Could you expand a bit on what you mean by "area optimization"? Was the optimization at an architectural level (as in changing the function and structure of units) or at a synthesis level (making the synthesizer choose smaller cells, improve area utilization and routing, using custom standard cells (FAST14????)).

Also, can you tell us if parts of the chip were built full-custom? It would seem like the shader units would be the perfect target for this. I had a theory that in R600/RV670, the shaders were synthesized/semi-custom while in RV770 the shaders are full-custom. This seems somewhat plausible due to the vast improvement in area that full-custom offers. Is there any truth to this?