Thursday, December 8th 2011

AMD Radeon HD 7900 ''Tahiti'' Pictured, 384-bit Memory Bus Confirmed?

Dec 8th, 2011 12:39 Discuss (117 Comments)

A Beyond3D forum member posted a mysterious picture of two graphics cards that could very well be engineering samples of AMD's true next-generation Radeon HD 7900 "Tahiti" graphics cards. The final products most probably won't look like these, with a bare red PCB, but it does look like the reference cooler design is ready. A more important feature in that picture is the spotting of traces for at least 11 memory chips, the 12th one (not highlighted) is apparently near the PCIe slot interface. The presence of 12 memory chips gives rumors of Tahiti featuring a 384-bit wide memory interface a shot in the arm. This will be the first AMD GPU in over 5 years to feature a memory bus wider than 256-bit. The R600 Radeon HD 2900 GPU featured a 512-bit GDDR4-capable memory interface.

Sources: Beyond3D Forums, VR-Zone

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117 Comments on AMD Radeon HD 7900 ''Tahiti'' Pictured, 384-bit Memory Bus Confirmed?

#26

pantherx12

cadavecaUm, that's not what I see(I see 8+6 in both cards, and pinout for 8x8):

www.techpowerup.com/forums/attachment.php?attachmentid=44623&stc=1&d=1323369311

I blame blurriness I can't see the edges :laugh:

Can see the one closest to the edge could be an 8 pin now, on the other card looks like it's the other way round XD

#27

mastrdrver

btarunrBTW, that is a huge GPU package.

Doesn't look any larger then the backside of my 5870s.

#28

cadaveca

My name is Dave

Whatever it is, it's dman exciting. Seeing cards now...does that mean we get a launch within weeks? One can hope...

#29

Casecutter

btarunrthat "Tahiti-XDR2" rumor

Me think's... AMD will hold that and refine it until the top Shelf Kepler's come. Either the XDR2 designation to the existing 7970 or a new model. Consider if they wait... could they release both a Single and Dual XDR2 :rolleyes:
That might send Kepler packing... :nutkick:

#30

Solaris17

Super Dainty Moderator

btarunrMaybe we could discuss memory mapping in another thread?

If you two like, I can spin related posts from this thread off into a new thread in the GPU forum.

So basically your going to change the address space?

#31

btarunr

Editor & Senior Moderator

Solaris17So basically your going to change the address space?

No, pressing buttons that change the "t=" value of those posts in the database.

Back to topic.

#32

Delta6326

It is 2x 8pin you can tell from the solder points. Now who know you may only need 1x 8 1x 6 to be able to run them.

How long do you think these are they look like they are slightly longer than that M/B so maybe 9.5 -10"?

Lets play a game name those other parts we have
ASUS Crosshair V Formula AM3+ AMD 990FX SATA 6Gb/s...
SanDisk Ultra SDSSDH-120G-G25 2.5" 120GB SATA II I...
CORSAIR Enthusiast Series TX850 V2 850W ATX12V v2....
Just can't figure out the ram or that case maybe a Corsair Obsidian Series 650D (CC650DW-1) Black Ste... hard to tell basing it off a couple screws I can see.

#33

GSquadron

From what i know they will make high end parts with xdr2 vram
so this is not a high end part. If it is, than there will be no xdr2 vram

#34

erocker

I doubt the final card will have two 8 pin adapters. Both Cayman and Cypress had two 8 pins on their "engineering samples".

#35

Solaris17

Super Dainty Moderator

erockerI doubt the final card will have two 8 pin adapters. Both Cayman and Cypress had two 8 pins on their "engineering samples".

I agree if anything they did it so they could beat the ES cards to get an idea of theoretical performance instead of basing it off of computer models.

#36

D4S4

just wanted to say that that's a f*cking awkward place for a 12th memory chip, especially since it's right between the gpu and pcie connector and there seems to be plenty of room on the other end of the "ring".

#37

btarunr

Editor & Senior Moderator

D4S4just wanted to say that that's a f*cking awkward place for a 12th memory chip, especially since it's right between the gpu and pcie connector and there seems to be plenty of room on the other end of the "ring".

As if placing VRM near display outputs wasn't awkward enough (on HD 6800 series reference boards). It doesn't matter.

#38

BrooksyX

Very nice. Do want!

#39

D4S4

btarunrAs if placing VRM near display outputs wasn't awkward enough (on HD 6800 series reference boards). It doesn't matter.

thb i never even saw that. seems that crosstalk and other interference are no longer an issue which is nice but one chip so close must have smaller latency than the others, i wonder how they've handled that. i know there are a lot of wavy traces going from memory chips on my x1800.

#40

WarraWarra

So vram only on one side of the card ?? surely they have vram on both sides of the card or 2x 12 capable ram chip places ??
Would be a waste to have ram on the back side, no cooling for it and only gpu on front under the cooling system.

If they follow the same as with the mGPU's then the top of the range gaming ones has xdr memory in either 2GB/4GB versions.

#41

radrok

GDDR5 doesn't need that much cooling, my 6990s have some ram on the back of the pcb and they've never had any problem even at 1450mhz.
What's really toasty is the GPU and VRMs

#42

Marineborn

i seen the supposid specs on these cards, apprently extremly nice, ill pick up 2 when it comes out. to replace my 2 6870's that will be sold at that time

#43

R_1

Looks and feels cheap! Where is the back plate?

#44

erocker

R_1Looks and feels cheap! Where is the back plate?

Since there's no components on the backside a backplate isn't needed. I'd rather not have a backplate trapping heat on the PCB anyways. It's also an engineering sample. Cayman's ES didn't have a backplate either, the retail 6970 did.

#45

Lionheart

XDR2 memory could be used for an eyefinity HD7970 version ^_^

#46

radrok

Also as an exclusive on the 7990 to gain more bandwidth?

#47

badtaylorx

R_1Looks and feels cheap! Where is the back plate?

what are you smokin???

i think it looks like they're goin back to a 5XXX style design.....LOVE IT

#48

DarkOCean

badtaylorxwhat are you smokin???

i think it looks like they're goin back to a 5XXX style design.....LOVE IT

my thoughts exactly.

#49

Cruise51

*drooling on myself*

8-pin might be for pushing clocks? Looks power hungry but that won't stop me from buying it.

#50

alexsubri

[yt]Vh78T--ZUxY[/yt]

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AMD Radeon HD 7900 ''Tahiti'' Pictured, 384-bit Memory Bus Confirmed?

117 Comments on AMD Radeon HD 7900 ''Tahiti'' Pictured, 384-bit Memory Bus Confirmed?

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