Information about AMD`s upcoming GPU Tonga have been leaked.

C

Cloudfire

Newcomer
I have found information about the upcoming mobile GPU "R9 M295X", codename "Tonga" on ozone3d.net.
For context, see previous leak here:
http://www.pcgameshardware.de/screenshots/811x455/2014/05/beyond3d-tonga-codexl-2-pcgh.jpg

It was leaked today and have various information about the chip, but doesnt tell anything about the number of shaders.

The chip was tested with OpenGL, something I am not familiar with, and if I compare R9 M295X against GCN 1.0 R9 M290X, I can see many differences listed down. But I don`t understand what is the change vs GCN 1.0.

Can you experts try to pin down the differences and what makes Tonga different than previous card?

R9 M295X @ ozone3d.net
R9 M290X @ ozone3d.net (PS: 8970M = R9 M290X)

Thank you
 
It's definitely a new graphics card.

The M290X is a Pitcairn clocked at 900MHz core, 1250MHz memory and sports 20 CUs (1280 unified shaders).

This new M295 is definitely another chip, since it has a lower clock at 800MHz, 1375MHz memory and 32 CUs (2048 unified shaders).
I can't tell either it's a new chip or the old Tahiti. I couldn't see any reference to the GCN version.

The fact that it uses 4GB suggests that it has a 256bit bus, not a 384bit one like Tahiti.
AMD could just have cut the memory bus like they did with Tahiti LE / Radeon HD7870 XT.



EDIT: Looking at the amount of OpenCL extensions, I can see that this M295 lists 24 extensions, like the new Bonaire and Hawaii chips with GCN1.1. All Pitcairn (mobile and desktop) and Tahiti chips list 21 extensions.
To be more specific, the new chips support "cl_khr_gl_event", "cl_khr_spir" and "cl_khr_d3d11_sharing" which the older GCN1.0 cards don't seem to support.

That, added with the fact that there's a 256bit bus and Tahiti is originally a chip for >200W cards, makes me believe this is a new chip.
If I had to guess, I'd say this is a chip with about the same execution resources as Tahiti but with a smaller memory bus, using GCN1.1 together with the energy/area efficiency boosts that were introduced with Bonaire and Hawaii.
Probably still made on 28nm, though.
 
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