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
RCoon
Forum Gypsy
Of course it will pair with the 7900 series, its essentially a sucky 7950 anyway right?
Posted on Reply
#2
brandonwh64
Addicted to Bacon and StarCrunches!!!
Hmmm this has me thinking that the LE can be unlocked some how with shader count...
Posted on Reply
#3
btarunr
Editor & Senior Moderator
by: RCoon
Of course it will pair with the 7900 series, its essentially a sucky 7950 anyway right?
Normally, we'd think it shouldn't because memory amount/bus/ lack of parity. Hence the excitement.

by: brandonwh64
Hmmm this has me thinking that the LE can be unlocked some how with shader count...
W1zzard is working on that.
Posted on Reply
#4
RCoon
Forum Gypsy
by: btarunr
Normally, we'd think it shouldn't because memory amount/bus/ lack of parity. Hence the excitement.



W1zzard is working on that.
I see, in which case i look forward to seeing people buy two 7870LE's and crossfiring them at 7950 speeds for a substantially low cost xD
Posted on Reply
#5
btarunr
Editor & Senior Moderator
by: RCoon
I see, in which case i look forward to seeing people buy two 7870LE's and crossfiring them at 7950 speeds for a substantially low cost xD
Exactly.
Posted on Reply
#6
RCoon
Forum Gypsy
by: btarunr
Exactly.
Can you give us a sneaky bit of info on how the cooler performs? EDIT: when it's in that crossfire
Posted on Reply
#7
m1dg3t
Pretty cool! Nice going there W1zz :pimp:
Posted on Reply
#8
btarunr
Editor & Senior Moderator
by: RCoon
Can you give us a sneaky bit of info on how the cooler performs? EDIT: when it's in that crossfire
Haven't done testing with that crossfire setup, but it's far from being the quietest card in its class.
Posted on Reply
#9
INSTG8R
Interesting. Very keen on seeing the results. Might even make me dip my toe back into the water with Crossfire(Last time was WAYYY back with X1900XT's) If they scale well seems like a great deal.

Not keen on using Club3D, wonder if Sapphire is gonna do any Tahiti LE's.
Posted on Reply
#10
btarunr
Editor & Senior Moderator
by: INSTG8R
Interesting. Very keen on seeing the results. Might even make me dip my toe back into the water with Crossfire(Last time was WAYYY back with X1900XT's) If they scale well seems like a great deal.

Not keen on using Club3D, wonder if Sapphire is gonna do any Tahiti LE's.
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).
Posted on Reply
#11
cadaveca
My name is Dave
I was hoping for a GTO model. :p


Still, good info, can't wait for the review!
Posted on Reply
#12
btarunr
Editor & Senior Moderator
by: cadaveca
can't wait for the review!
You don't have to ;)
Posted on Reply
#13
cadaveca
My name is Dave
by: btarunr
You don't have to ;)
:laugh:



BTA>>>ME

:slap:


:roll:



I like to wait anyway. I mean, you already know I'm a bit off-kilter...:p
Posted on Reply
#14
Frick
Fishfaced Nincompoop
by: cadaveca
I was hoping for a GTO model. :p


Still, good info, can't wait for the review!
That would have been nice. GTO + unlocks would be awesome.
Posted on Reply
#15
Socram13
I´m waiting for that 7870 LE review for some weeks, hope that it manages to be on pair with GTX 660 Ti.
Posted on Reply
#16
3870x2
Can the 7950 be unlocked to 7970? Sorry for the ignorance, I haven't done my homework.
Posted on Reply
#17
W1zzard
by: 3870x2
Can the 7950 be unlocked to 7970? Sorry for the ignorance, I haven't done my homework.
No. there are no shader unlocks for HD 7000 Series
Posted on Reply
#18
Widjaja
Will be interesting to see the review for this card.
Posted on Reply
#20
m1dg3t
by: W1zzard
No. there are no shader unlocks for HD 7000 Series
The stop gaps are on the silicone level?

For example, the 7950 I have, is identical physically in appearance to a referrence 7970 but there is no chance of getting it to function as such?
Posted on Reply
#21
cadaveca
My name is Dave
by: m1dg3t
The stop gaps are on the silicone level?

For example, the 7950 I have, is identical physically in appearance to a referrence 7970 but there is no chance of getting it to function as such?
Nope. I'm running a 7970 BIOS anyway, makes ZERO difference, except in "stock" clocks and voltages.

I kinda thought maybe they hid some PCB bridge under the metal ring that goes around the core or something, but getting that off isn't going to be very easy. It really does seem as though there are actual physical disabling of the core, and how or where is not easily found.
Posted on Reply
#22
W1zzard
There are fuses inside the die that can be blown in the late production process. This is a permanent change.
Posted on Reply
#23
WarEagleAU
Bird of Prey
IF W1zzard manages to unlock the cores and what have you, what essentially brought me to TPU back in 2006 the Radeon unlocking of an X850, will be huge. I would definitely upgrade my 6870 to a 7870 LE no problem :)
Posted on Reply
#25
INSTG8R
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).
I will chock that up to Sapphires level of quality that they have taken a pass on these :cool:

by: WarEagleAU
IF W1zzard manages to unlock the cores and what have you, what essentially brought me to TPU back in 2006 the Radeon unlocking of an X850, will be huge. I would definitely upgrade my 6870 to a 7870 LE no problem :)
Hehe! "Young Fella" ;) I ended up here looking for info on how to unlock my 9800 Pro to XT. I was completely successful and became a bit of a "guru" on the "Can I unlock mine?" and I never left :pimp: (BTW it was a Sapphire and my still standing loyalty thru every Gen since)
Posted on Reply
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