AMD: R8xx Speculation

[Groo The Wanderer]

Didn't take that long... http://www.fudzilla.com/content/view/15879/1/

Yeah, but I couldn't say exactly when the drop date was/is.

-Charlie

 

[Kaotik]

Didn't take that long... http://www.fudzilla.com/content/view/15879/1/

Whoa, was expecting writer to be Fuad when they mentioned 4890 and 260 as equal performers, not 4890 and 275

 

[bowman]

It was 32. Even Xenos has 16

Where are the Evergreen die shots?

 

[3dcgi]

The only score that 4850 is clearly worst is the GPU Cloth (vertex/geometry shading test) (4770 has +20% perf. in relation with 4850 in this test)

I suspect this is either because geometry set-up engine has higher clock speed or it is interpolation related.

RV770 had 32 interpolators and 40 TUs.
the 5870 how many interpolators it has?
Is it per SIMD? (10+10)
Or is it per TU? (40+40)

Vantage Cloth test is definitely not interpolator limited. Most of the render time is spend simulating the cloth physics and no pixels are generated during this time.

 

[elsence]

Vantage Cloth test is definitely not interpolator limited. Most of the render time is spend simulating the cloth physics and no pixels are generated during this time.

Yes it doesn't seem to be interpolation related. (my second assumption)

That's why my first assumption was about geometry set-up rate, which the 4770 is faster than 4850 (but in pure vertex shading speed the 4850 should be more or less equal to 4770, 625MHz 800SPs vs 750MHz 640SPs)

 

[mczak]

I'm actually a bit surprised the 5750 has almost as fast gddr5 ram as 5770 but deactivated simd. Which begs the question why didn't AMD go with slower (~1Ghz) gddr5 and full simds? Is there almost zero price difference between faster and slower gddr5 or are yields bad enough that AMD needs a high-volume salvage part this round?

 

[neliz]

I'm actually a bit surprised the 5750 has almost as fast gddr5 ram as 5770 but deactivated simd. Which begs the question why didn't AMD go with slower (~1Ghz) gddr5 and full simds? Is there almost zero price difference between faster and slower gddr5 or are yields bad enough that AMD needs a high-volume salvage part this round?

Price difference is minimal

 

[ShaidarHaran]

I'm actually a bit surprised the 5750 has almost as fast gddr5 ram as 5770 but deactivated simd. Which begs the question why didn't AMD go with slower (~1Ghz) gddr5 and full simds? Is there almost zero price difference between faster and slower gddr5 or are yields bad enough that AMD needs a high-volume salvage part this round?

Where do you see that the 5750 has SIMD(s) deactivated?

I thought both 57xx parts were 10 SIMD unit parts. The earlier rumors about 5770 having 14 SIMDs have been disproven.

 

[AlNom]

Where do you see that the 5750 has SIMD(s) deactivated?

720SPs

Which begs the question why didn't AMD go with slower (~1Ghz) gddr5 and full simds? Is there almost zero price difference between faster and slower gddr5 or are yields bad enough that AMD needs a high-volume salvage part this round?

Possibly both power and wanting a high yield part for the "masses." Yields don't have to necessarily be bad...

 

[no-X]

Where do you see that the 5750 has SIMD(s) deactivated?

I thought both 57xx parts were 10 SIMD unit parts. The earlier rumors about 5770 having 14 SIMDs have been disproven.

HD5750
1.01 TFLOPs
core: 700MHz
SPs: 720
0.5-1GB 4.6 GBps GDDR5
power: 86/16W

HD5770
1.36 TFLOPs
core: 850MHz
SPs: 800
1GB 4.8 Gbps GDDR5
power: 108/18W

 

[ShaidarHaran]

Where do these specs come from? Not saying they're wrong, just so many different specs floating around out there...

 

[w0mbat]

They are officialy from AMD.

 

[AlNom]

Some leaked slides earlier in the thread (if they're still there).

 

[no-X]

The slides are everywhere now

 

[elsence]

It must be the price.

Also the 5850 (HIS 5850) has 5Gbps ICs but ATI clocked them at 1GHz.

http://tpucdn.com/reviews/HIS/HD_5850/images/memory_small.jpg

5750 (mymypc card sample) ICs are from Hynix.

http://www.mymypc.com/images/vga/mymypc-hd5750-4.jpg

Other VGA brands may have other brand ICs (i mean vice versa)

With 1150MHz the 5750 will probably be less bandwidth limited than 4850.

Even in the (extreme case) color fill rate test (which by itself doesn't say much about bandwidth limitation in games...) it delivers more than the clock difference (700MHz 16ROPs / 625MHz 16ROPs)

Overall (if the specs are true) the 5750 1GB should be around +10% faster (+5% up to +15%) (depending on the game) than a 4850 1GB. (1920X1200 4AA 16AF)

And the 5770 will be probably around +5% faster than 4870 1GB speed (-10% up to +15%) (depending on the game) (1920X1200 4AA 16AF)

 

[ShaidarHaran]

Great, thanks guys. I may be replacing my 8800 GT with a 5770 once the price drops closer to $100.

 

[no-X]

elsence: Expect HD5770 performance to be a bit closer to HD4870-512 than to HD4870-1024.

 

[-The_Mask-]

They are officialy from AMD.

LOL I don't think so, too many things are wrong.

 

[Silent_Buddha]

Besides that's just memory for the reference board. It only makes sense that AIB's would be able to put on lower speed memory if they wished. Unless it isn't compatible with the new power saving schemes?

Regards,
SB

 

[elsence]

no-X: We just doing predictions, only the reviewers know the real difference.

lol, we don't even know if these are the specs 100%. (for example:16 color ROPs?, copy paste from previous gen detailed specs page?)

5770 will have 1GB of mem.

4870 1GB (750MHz/900MHz GDDR5) is 0% up to +25% faster (depending on the game) than an oc 4850 1GB (750MHz/1,2GHz GDDR3) (1920X1200 4AA 16AF)

How much faster the 5770 (800SPs case, if true...) will be in relation with the oc 4850?
I would say +10% up to +20% depending on the game.

So for some games that the engine is not bandwidth limited sensitive the 5770 1GB will be faster and for other games that the engine is sensitive to memory bandwidth the 4870 1GB will be faster. (1920X1200 4AA 16AF)

It depends from the game/resolution/quality options/AA & AF level...

Anyway, we will see in a few days.