AMD RV770 refresh -> RV790

W

w0mbat

Newcomer
TechPowerUp posted an article a few days ago about a upcoming RV770 refresh called RV790: http://www.techpowerup.com/75685/AMD_to_Give_RV770_a_Refresh_G200b_Counterattack_Planned.html

This would fit perfect to AMDs plans to release a new highend/refresh every 6 month.

What do u expect of RV790? Do u thing it will be just a small refresh w/ higher clks or do u think AMD will maybe widen the chip? Will they add more SIMDs, get PowerPlay 2.0 working and bump up the clks?

My guess (pure speculation!):

q407 RV670 - 55nm - 4 SIMDs (320SPs, 16TMUs, 256bit@1,125GHz GDDR4) - 194mm²
q208 RV770 - 55nm - 10 SIMDs (800SPs, 40TMUs, 256bit@1,8GHz GDDR5) - 260mm²
q408 RV790 - 55nm - 12 SIMDs (960SPs, 48TMUs, 256bit@2GHz+ GDDR5) - < 300mm²
q209 RV870 - 40nm - ...

This also would explain why there are rumors on the net that RV870 will have 960SPs - cause they confused RV870 w/ RV790.

So, whats ur guess?
 
Higher clocked refresh presumably.

If anything I'd be expecting them to go smaller on 55nm rather than bigger:
Chop out the CF sideport & a couple of SIMDS to get back to the Plan B design.
Could they get enough power overhead/extra clock to make up for the loss of width?
 
If they went down to 8 cores they'd have to get 950MHz just to retain the ALU and TU performance. Fillrate would go up of course, by 27%. But I suspect that texturing is the more important bottleneck in RV770 right now, so reducing the core count is extremely unlikely.

Jawed
 
BTW, if you release an over clocked card with otherwise same spec, is it really a refresh? I would have thought that you will make atleast some changes to the silicon to call it a refresh.
 
rpg.314 said:
BTW, if you release an over clocked card with otherwise same spec, is it really a refresh? I would have thought that you will make atleast some changes to the silicon to call it a refresh.
Click to expand...
8800Ultra, 7800GTX-512 and X850XTPE were all refreshes in the "same chip, increased clocks" mould.

"Overclocked" is moot if the standard SKU is at the new, higher, clocks.

Jawed
 
"Overclocked" is moot if the standard SKU is at the new, higher, clocks.
Click to expand...

I wonder how they do that though. 8800Ultra was so expensive that they could have very well just sold those parts that clocked well. I have no idea about the other two cards you mentioned.

Higher clocks from the same silicon. If they could have run it faster earlier, wouldn't they have clocked it higher at the time of the launch?
 
I too think that RV790 will be an higher clock and maybe lower power RV770. ATI has the feature advantage with DX10.1 (so they don't need to put new features and can even kill the sideport), has definitely a die size advantage and if GT206 is really an 8-10% higher performance GT200, then with a 850-950 MHz RV770 (13-25% more GPU clock) the performance gaps are likely to be the same as now (or even better for ATI). Maybe the problem of such a solution could be the yield, and the thermal specifications (due to the smaller surface of RV770, is more difficult to properly cool it down with respect to a bigger chip like GT200-GT206)
 
Over the lifetime of a chip it gets easier to make. Yields improve, which offers the opportunity for the IHV to increase clocks.

http://www.tsmc.com/download/english...chure_2007.pdf

See page 10 (11th in PDF).
Click to expand...

I had a look at it. The increasing yields that were shown were for a process, and not specific to a product. 55nm process has been around for ~a year now, so the defect rate must be running low already. Since the improvements apply for all the chips coming off new wafers, I suppose it makes binning-for-faster-chips easier (in that you have more chips availaible, so more of them run faster).

Am I on a right track here?
 
I presume number of working chips per wafer improves as well as some electrical parameters.

Jawed
 
w0mbat said:
TechPowerUp posted an article a few days ago about a upcoming RV770 refresh called RV790: http://www.techpowerup.com/75685/AMD_to_Give_RV770_a_Refresh_G200b_Counterattack_Planned.html

This would fit perfect to AMDs plans to release a new highend/refresh every 6 month.

What do u expect of RV790? Do u thing it will be just a small refresh w/ higher clks or do u think AMD will maybe widen the chip? Will they add more SIMDs, get PowerPlay 2.0 working and bump up the clks?

My guess (pure speculation!):

q407 RV670 - 55nm - 4 SIMDs (320SPs, 16TMUs, 256bit@1,125GHz GDDR4) - 194mm²
q208 RV770 - 55nm - 10 SIMDs (800SPs, 40TMUs, 256bit@1,8GHz GDDR5) - 260mm²
q408 RV790 - 55nm - 12 SIMDs (960SPs, 48TMUs, 256bit@2GHz+ GDDR5) - < 300mm²
q209 RV870 - 40nm - ...

This also would explain why there are rumors on the net that RV870 will have 960SPs - cause they confused RV870 w/ RV790.

So, whats ur guess?
Click to expand...

~300mm² I would not consider RV chip - but more pushing into high end chip. "Almost"
 
Wouldn't mind seeing a 12SP unit, means I could go buy some second-hand 4870's for cheap :)
 
Jawed said:
If they went down to 8 cores they'd have to get 950MHz just to retain the ALU and TU performance. Fillrate would go up of course, by 27%. But I suspect that texturing is the more important bottleneck in RV770 right now, so reducing the core count is extremely unlikely.
Click to expand...
If 9600GT vs. 9800GT benchmarks are anything to go by, fillrate/BW and setup are much more important than ALU and TU performance. The two are very close in performance.

Add 9% to the 4830 scores (due to clock speeds) in almost any game benchmark and it'll be right at the heels of the 4850. My guess is that 850MHz is all you'll need for a 8-SIMD RV790 to outrun the 4870 overall.

Anyway, the SIMDs are so small that it's probably not worth cutting. Overall they're what, <40% of the die? Going to 12 SIMDs, as w0mbat suggests, would only add ~20mm2.
 
Raqia said:
From this:

http://www.tgdaily.com/content/view/40185/139/

my guess is that the RV790 is going to be a 40nm part.
Click to expand...

If RV790 comes Q4 2008 it will be on 55nm - because 40nm tech will not be available until Q2 2009. The only refresh I expect from ATI is faster core clock speed this year unless if ATI wants to surprise me :)
People predicted that RV870 will be about 140mm2, but I got a feeling that they mix up with RV790 - if their is such a chip exist.


EDIT: RV870: http://en.hardspell.com/doc/showcont.asp?news_id=3768
 
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"Meyer noted that 40 nm ATI Radeon GPUs 'are just around the corner' and set for a mid-2009 refresh for the firm’s current graphics product line."

But but "around the corner" sounds so much sooner! :'(
 
Speculation of refresh ATI GPU Q4-2008; RV770 can be clocked as high as 855MHz GPU stable operation http://www.techarp.com/showarticle.aspx?artno=580&pgno=5

If Radeon HD 4870 runs 750core/900memory. And If ATI cranks GPU clock frequency to 850MHz core / 1100MHz memory - the speculation we are only looking at ~10% performance boost.

ATI Radeon HD 4890
RV790
850MHz core
1100MHz GDDR5 ~140GB bandwidth
55nm tech
800 streams
40TMU's
16ROP's
10 SIMDs

-OR- Huge speed bump upgrade

ATI Radeon HD 4970
RV790
800MHz core
1000MHz GDDR5 ~128GB bandwidth
55nm tech
960 streams
48TMU's
16ROP's
12 SIMDs
 
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