Thursday, December 8th 2011

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

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?

#101
crazyeyesreaper
Not a Moderator
gotta say thats fud lol that article is still referencing PCIE 3.0 and XDR2 i doubt 7000 series will be PCIE 3.0 i say this because AMD;s own chipset coming out NEXT year is still PCIE 2.0,
Posted on Reply
#102
pantherx12
crazyeyesreapergotta say thats fud lol that article is still referencing PCIE 3.0 and XDR2 i doubt 7000 series will be PCIE 3.0 i say this because AMD;s own chipset coming out NEXT year is still PCIE 2.0,
At-least they've gone with more reasonable results then usual :laugh:


If it is true they must of given tessellation a big boost as metro is over double the performance.
Posted on Reply
#103
mastrdrver
theoneandonlymrk12x128 Mb chips would equal 2gig im only speculating from rumours i heard and only sayin it cos no one else is

www.xbitlabs.com/news/memory/display/20090212111407_Samsung_Begins_to_Produce_7GHz_GDDR5_Memory.html

samsungs new gddr5 7GHz capable

and with rumours imho i see a 256 bit memory bus between gfx gpu and mem plus a seperate sideband sort of 128bit iommu bus making what they will call a 384bit bus and more system to gpu bandwith utilised

like i say a 3rd on die DMA maybe 4 in total
AMD is not going to use 7Ghz chips. They take more voltage then the ones that are used on the 6970. Also realize that Tahiti with its 384 bit bus will not be clock as high as previous AMD cards since the wider bus puts a larger strain on the controller. It would require more voltage to run the wider bus at previous AMD GPU memory speeds.

Besides, with the wider bus you do not need the higher clock just to get the bandwidth up.
Posted on Reply
#104
crazyeyesreaper
Not a Moderator
pantherx12At-least they've gone with more reasonable results then usual :laugh:


If it is true they must of given tessellation a big boost as metro is over double the performance.
metro dosent use tessellation that much it uses less tessellation then every other dx11 game that uses it what hits gpus hard in metro is lighting shadows and direct compute
lighting hits it hard because it uses subsuface scattering think of it this way put a flashlight under your fingers the red you see is light passing through upper layers of skin Metro uses that technique among others
Posted on Reply
#105
Benetanegia
The thing that hits my GTX 460 harder in Metro is the DX11 depth of filed, by far. Without tesselation and DOF I get around 40 fps. Enabling tesselation brings it down to 35 fps or so. DOF (w/o tesselation) brings it down to 25. With both enabled it's 20 fps or so.

I don't know if DOF is a real D3D11 feature or if it uses compute.

There's many ways in which Metro could see a huge improvement from Tahiti, but I agree that tesselation doesn't seem like one. Even the much much hgher memory bandwidth makes more sense to me.
Posted on Reply
#106
crazyeyesreaper
Not a Moderator
Depth of Field in Metro 2033 uses Direct Compute

its effective but as you can tell no current gpus are really ready for full on direct compute tasks in real time while running a game,

DOF via Direct Compute has no improvement in quality vs current methods but has an insane performance impact, essentially tho Direct Compute does allow them to add more to the render pipeline without making it longer, thats the real benefit so eventually this will become a good thing currently gpus arent powerful enough for it .
Posted on Reply
#107
pantherx12
crazyeyesreapermetro dosent use tessellation that much it uses less tessellation then every other dx11 game that uses it what hits gpus hard in metro is lighting shadows and direct compute
lighting hits it hard because it uses subsuface scattering think of it this way put a flashlight under your fingers the red you see is light passing through upper layers of skin Metro uses that technique among others
I stand corrected, well in that case if this is real math performance has gone up?
Posted on Reply
#108
crazyeyesreaper
Not a Moderator
correct if there benching metro with DOF on then it is possible that a 7970 could see that kind of performance gain.

and since a 6970 stock with all settings turned on gets me around that same mark performance wise then yes at least the 6970 numbers on that chart look correct, and should the GCN be targeted like CUDA cores are towards improved mathmatical performance and super computing type tasks then yes Direct Compute effects would no longer stress the architecture, but again i still call fud on that graph in its entirety
Posted on Reply
#109
pantherx12
crazyeyesreapercorrect if there benching metro with DOF on then it is possible that a 7970 could see that kind of performance gain.

and since a 6970 stock with all settings turned on gets me around that same mark performance wise then yes at least the 6970 numbers on that chart look correct, and should the GCN be targeted like CUDA cores are towards improved mathmatical performance and super computing type tasks then yes Direct Compute effects would no longer stress the architecture, but again i still call fud on that graph in its entirety
Well after bulldozer I know to never get overly excited again that's for sure :laugh:

Assuming everything does go well and they come out with decent performance I'll probably grab a 7970.

Last top end card I had was 4870 and well, it was only really midrange XD
Posted on Reply
#110
techtard
The 4870 was a beast. Mid range prices, top end grunt. I have a friend who still uses a pair in crossfire. I sold him mine and went 5850 for an inexpensive upgrade.

I haven't upgraded yet, surprisingly my ddr2 based AM2+ rig is still getting the job done so far.
Granted, I don't play the most demanding of the newer games.

Depending on how my rig runs SW:TOR I may just keep this beast until it dies.

Waiting to see that AMD has up it's sleeve for the 7xxx series, and nVidia for their next GTX series.
Posted on Reply
#111
mediasorcerer
Good to see you here again tard, im waiting too why not?
Posted on Reply
#112
pantherx12
techtardThe 4870 was a beast. Mid range prices, top end grunt. I have a friend who still uses a pair in crossfire. I sold him mine and went 5850 for an inexpensive upgrade.

I haven't upgraded yet, surprisingly my ddr2 based AM2+ rig is still getting the job done so far.
Granted, I don't play the most demanding of the newer games.

Depending on how my rig runs SW:TOR I may just keep this beast until it dies.

Waiting to see that AMD has up it's sleeve for the 7xxx series, and nVidia for their next GTX series.
I disliked mine, I had it for a week and sold the entire system that it was with :laugh:

Had more fun with a 9800 gt, and then a 3800 series crossfire set up XD
Posted on Reply
#113
amadzack
i Dont like cheap Red pcb..wait2 where the blackplate?:banghead:
Posted on Reply
#114
Nick89
so how much memory will it have? 1536mb? It has 12 memory chips and if each chip is 128 megabytes that equals 1536mb or ram.
Posted on Reply
#115
cadaveca
My name is Dave
3GB the rumours state, not 1536MB. Apparant launch is tomorrow, so we'll find out the details tomorrow.
Posted on Reply
#116
Delta6326
amadzacki Dont like cheap Red pcb..wait2 where the blackplate?:banghead:
Don't worry it should have black PCB the red is just for sample. No need for backplate.
Posted on Reply
#117
cadaveca
My name is Dave
Delta6326No need for backplate.
I think probably 80% of people don't care if the backplate is functional or not. Bare PCBs suck, and backplates are cheap.
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