Friday, December 7th 2012

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!

We successfully managed to pair the Club 3D HD 7870 jokerCard with a Radeon HD 7950 and HD 7970 (reference). We casually put it through 3DMark 11 and Sleeping Dogs, and found the contraptions to scale fairly well. We noticed some micro-stutter in 3DMark 11, but Sleeping Dogs felt smooth. This could be great news for current HD 7900 series owners who can upgrade to CrossFire for a modest $249~269. We even tried our luck at unlocking disabled shaders (stream processors), which didn't work. AMD used the mod-proof fuses method to lock the shaders. Check out our Club 3D HD 7870 jokerCard review.
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39 Comments on Radeon HD 7870 "Tahiti LE" Can Pair with HD 7900 Series in CrossFireX

#1
blibba
Nobody will be unlocking any HD68** or HD7*** chips - it's impossible, as clearly stated by Wizz above.

I'd be interested to see how 7950+7930 performs in CF vs. 2*7950.

(Yeah, I just called it a 7930 :eek:)
Posted on Reply
#2
Ferrum Master
Nice I just ordered a 7970 at last, going to ditch the green camp, Huang had too much of my money lately, need to support AMD just for the sake of the competition.

So after cracking hours of tech reviews and RMA rates... NO SAPPHIRES OR GIGABYTES. Those cheapskates uses poor components that result in abnormalities, like ringing inductors at load and poor OC with artifacts... ASUS, MSI and some others frankly doesn't suffer from it at such rates. Myself I took the OEM one, because of the turbine solution only.
Posted on Reply
#3
T4C Fantasy
CPU & GPU DB Maintainer
by: Ferrum Master
Nice I just ordered a 7970 at last, going to ditch the green camp, Huang had too much of my money lately, need to support AMD just for the sake of the competition.

So after cracking hours of tech reviews and RMA rates... NO SAPPHIRES OR GIGABYTES. Those cheapskates uses poor components that result in abnormalities, like ringing inductors at load and poor OC with artifacts... ASUS, MSI and some others frankly doesn't suffer from it at such rates. Myself I took the OEM one, because of the turbine solution only.
check out tpus database for card stats like length, and performance figures ^^i think every hd7970 is in there if not tell me

http://www.techpowerup.com/gpudb/296/AMD_Radeon_HD_7970.html

http://www.techpowerup.com/gpudb/365/AMD_Radeon_HD_7970_GHz_Edition_(PCIe_3.0_x16).html
Posted on Reply
#5
TheGuruStud
by: ferrum master
aww those inches... Tpu could be more democratic and add metric system option :p
commie!

;)
Posted on Reply
#6
Frick
Fishfaced Nincompoop
by: Ferrum Master
Aww those inches... TPU could be more democratic and add metric system option :p
But it says mm under inches.
Posted on Reply
#7
T4C Fantasy
CPU & GPU DB Maintainer
by: Ferrum Master
Aww those inches... TPU could be more democratic and add metric system option :p
yes its already in, just click on the card and it shows mm right under inches
Posted on Reply
#8
Ferrum Master
by: TheGuruStud
commie!

;)
Don't even try to pull that question up even as a joke for my countrymen, do some history studies... ;).

by: T4C Fantasy
yes its already in, just click on the card and it shows mm right under inches
Yeah I noticed that now, thanks. I was just looking in the other Other Changes section, where the imperial numbers where only present :), there for I took it as default.
Posted on Reply
#9
BallackCFC
Has anyone tried to crossfire a 7870 tahiti LE with a 7970? I purchased the 7870 not too long ago but after installing it it didnt work (I did turn crossfire on in CCC). Any ideas? Both cards are Sapphire as well.
Posted on Reply
#10
tastegw
by: btarunr
Sapphire won't do a Tahiti LE. They hate it. The only other brands are PowerColor (HD 7870 Myst) and VTX3D, and those cards are virtually identical to Club3D's card, since they're made on the same exact production line (TUL).
This is an XT SAPPHIRE 100354XTL Radeon HD 7870 XT w/Boost 2GB 2...
Is it not the same as the LE's?
Specs seem the same, maybe I'm missing something

At erocker

"We successfully managed to pair the Club 3D HD 7870 jokerCard with a Radeon HD 7950 and HD 7970 (reference). We casually put it through 3DMark 11 and Sleeping Dogs, and found the contraptions to scale fairly well. We noticed some micro-stutter in 3DMark 11, but Sleeping Dogs felt smooth. This could be great news for current HD 7900 series owners who can upgrade to CrossFire for a modest $249~269. We even tried our luck at unlocking disabled shaders (stream processors), which didn't work. AMD used the mod-proof fuses method to lock the shaders. Check out our Club 3D HD 7870 jokerCard review."

From the OP

What question were u answering there.
Posted on Reply
#11
erocker
by: tastegw
What question were u answering there.
The one I quoted. I was wrong, read a couple google searches and must of read people just having problems. Also based on the fact I haven't heard of it being done. But, cool that it works.... I'd kind of like to try it out.
Posted on Reply
#12
tastegw
Ya, would be a cheaper upgrade for some folks
(Upgrade as in adding a 2nd or 3rd card)
Posted on Reply
#13
Krantzstone
Sapphire HD 7870 XT

by: tastegw
This is an XT SAPPHIRE 100354XTL Radeon HD 7870 XT w/Boost 2GB 2...
Is it not the same as the LE's?
Specs seem the same, maybe I'm missing something

At erocker

"We successfully managed to pair the Club 3D HD 7870 jokerCard with a Radeon HD 7950 and HD 7970 (reference). We casually put it through 3DMark 11 and Sleeping Dogs, and found the contraptions to scale fairly well. We noticed some micro-stutter in 3DMark 11, but Sleeping Dogs felt smooth. This could be great news for current HD 7900 series owners who can upgrade to CrossFire for a modest $249~269. We even tried our luck at unlocking disabled shaders (stream processors), which didn't work. AMD used the mod-proof fuses method to lock the shaders. Check out our Club 3D HD 7870 jokerCard review."

From the OP

What question were u answering there.
Yeah, the Sapphire 7870 XT is a Tahiti LE card:
"The SAPPHIRE HD 7870 XT with Boost delivers a new price:performance point to the series. It is based on AMD's Tahiti architecture with its 256-bit memory interface, and 1536 stream processors and 96 Texture units, unlike the remainder of the HD 7800 series that uses the Pitcairn architecture. Configured with 2GB of high speed GDDR5 memory running at 1500 MHz (6GHz effective) the SAPPPHIRE HD 7870 XT has a core clock of 925MHz which dynamically rises to 975MHz with PowerTune Boost, AMDs dynamic performance enhancement for games."

More info here: http://www.techradar.com/reviews/pc-mac/pc-components/graphics-cards/sapphire-radeon-hd-7870-xt-1130535/review

I was _this_ close to getting it, but ended up getting the PowerColor MYST instead because it was cheaper, and the Sapphire was sold out anyway. I'm told the Sapphire has a better cooler, so that might be worth it for the extra cost of an aftermarket cooler for people planning on OC.
Posted on Reply
#14
NeoXF
ATM, R7790s and R7870XTs are best-buys, and to a lesser degree GTX660/GTX660Tis, in my country at least, not sure what's best for higher-end, but then again, there's bigger and bigger diminishing returns when going higher end.
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