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

Radeon HD 7870 "Tahiti LE" Can Pair with HD 7900 Series in CrossFireX

While testing Club 3D Radeon HD 7870 jokerCard, one of the three Radeon HD 7870 "Tahiti LE" graphics cards you can buy, we discovered that it can pair with Radeon HD 7900 series cards in CrossFireX. Our VGA testing lab, which has battened down the hatches for winter (lack of VGA launches), spent a lot of time toying with Club 3D's card and while brainstorming for the review's conclusion, it came up that HD 7870 Tahiti LE is "bad" because it can't pair with common HD 7870 or HD 7850 "Pitcairn" graphics cards. A bulb supernova just went off over our heads: "...sure Tahiti LE won't pair with Pitcairn, but will it pair with HD 7900 series "Tahiti", which have more stream processors, and more memory?" The answer turned out to be yes!

by: brandonwh64--- Hmmm this has me thinking that the LE can be unlocked some how with shader count...
by btarunr--- W1zzard is working on that.
;)
 
So you can pair it with a 7900 series card for CF? Is that something people will want to do?

Like said on the article, off course you can.. Now the problem remain allways the same when you mix different performance level cards:

- memory side: the lower density on one cards will bring the higher density memory card to run at the same level: ( if one card have 1.5gb and the other have 3gb, both will run with 1.5gb ) .

The only case i have usea config in this style was the X1950xtx + X1900XTX, both overclocked core at the same speed, but not the memory: ( same amount of ram, but the GDDR4 used on the X1950XTX was too fast for clock the X1900XTX GDDR3 memory at this speed, so both ram was run on their own stock speed ) But there again if the clock speed of the GDDR was different, both have the same density of ram (1gb) .

- Performance side: one card will be choose more offtly for render the frame depending the performance difference between both cards. it will finish by degrade micro stuttering experience. ( i have make the test by oc one card and keep the other at stock, the experience is allready bad with a 100mhz difference ).

- Whatever is the SLI or CFX configuration, for the best experience you want use the same card.. so 2x 7870 "Thaiti LE", 2x 7950 or or 2x7970..

Outside than that, the 7870LE is close of the 7950 in many case performance side, so the only problem is more the memory. ( just oc the 7870 Thaiti a bit for resolve performance difference )
 
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First I'd read about that, though I generally avoid dual gpu reviews because of microstutter so it's not suprising.

Is AMD even aware of it is the question.
 
A FPS limiter would still be something new for CCC though.
Not only that but an option to render frames ahead would also be a nice addition. For both single gpu and CF.
 
7900 series, including CF does really well in Hitman Absolution
If you aren't sensitive to microstutter, yes:
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If you think everyone's system behaves like this one above sample then yes.

But in real world it doesn't ...

Also weird is that the TR results show a 660Ti beating the 7950, while at [H] the results are completely reversed. Maybe it has to do with one running a highly OC'ed 2600K with cat12.11B11 and the other a baseline 3820 with CAT12.11B8? I personally don't think an 3820 is a good CPU for Gaming.
 
Also weird is that the TR results show a 660Ti beating the 7950, while at [H] the results are completely reversed. Maybe it has to do with one running a highly OC'ed 2600K with cat12.11B11 and the other a baseline 3820 with CAT12.11B8? I personally don't think an 3820 is a good CPU for Gaming.

Exactly, this can be caused by many things:
- X79 famous PCIe compatibility issues
- Driver
- HD7950 Boost BIOS
- other computer component

Obviously this issue is real and can happen on many systems, but so far we have a sample of one who is noticing it visually (see posted videos on TR website) as well as presented sampled data. But that still is one sample from many thousands cards sold and at least few hundred cards reviewed by testers.
If I had Hitman or Skyrim I would put some effort and ran few tests to verify Tech Report results.
 
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