AMD Radeon R9 M295X Mobility Chip To Feature Tonga GPU – Includes 32 Compute Units

Over buddies over at Videocardz have
got hands on some exclusive information regarding AMD’s upcoming Radeon
R9 M295X mobility chip which features the latest Tonga GPU
architecture. The Tonga GPU which is AMD’s new architecture is part of
the new Volcanic Islands GCN 2.0 line which is built to deliver better
power efficiency.

AMD Radeon R9 M295X Mobility Chip To Feature Tonga GPU

Leaked last month, we came to know that the Tonga GPU architecture
is being built on a new architecture which is presumably the GCN 2.0
design and not the GCN 1.1 architecture which has been featured on
Bonaire and Hawaii. The Tonga graphics architecture will be built on the
28nm node from Global Foundries and would feature a new design scheme
introducing latest architectural improvements such as new ACE
(Asynchronous Compute Engine) Units and more focus towards compute
shaders. It is also mentioned that Tonga will retain the basic
technologies of the Radeon lineup such as Mantle, TrueAudio and XDMA for
CrossFire support.

Now Videocardz was able to find some specifications of the Tonga GPU
which is meant to replace the Pitcairn and its rebranded subsidiaries
that include Curacao on desktop and Neptune on mobility front.
Technically, the Tonga GPU falls in line with the Tahiti GPU but due
enhanced efficiency, it’ll be aimed towards the same range as AMD’s
Pitcairn series cards (Radeon R9 270 / Radeon R9 270X / Radeon R9
M290X). The interesting thing is that Tonga will feature 32 compute
units but since the architecture is slightly improved, we don’t know
whether the stream processor count would remain the same. Otherwise we
are looking at 2048 stream processors for each compute unit that
includes 64 processors. The GPU in such a case will feature 128 TMUs and
32 ROPs which is the standard for Tahiti GPU along with a 256-bit bus
width which seems like a downgrade compared to Tahiti but that could
explain why its aimed as a Pitcairn replacement.

The Tonga GPU being a mobility chip confirms that its efficient
enough to be adopted in high-end notebook and mobility devices. AMD for a
reason didn’t went to integrate Tahiti or Hawaii into high-performance
notebooks due to their high power consumption. Tonga might just change
the game and offer competitive performance against the GeForce GTX 880M
which is a full GK104 core in mobility form factor. Though the
mainstream note-books featuring the GeForce GTX 860M and 850M Maxwell
cores will still look like a better power efficient offering.

Clock speeds at reference are not mentioned but the core will operate
at a max boost clock of 800 MHz and the memory would operate at 1375
MHz (5.5 GHz effective) clock speed. The AMD Radeon R9 M295X mobility
chip will end up with 4 GB GDDR5 memory. Its desktop equivalent which is
likely to use the Radeon R9 275X branding will feature the same GPU
with better clock speeds. The key focus is power efficiency on Tonga GPU
hence we can see some good numbers in that regard.

Videocardz also
mentions that since AMD is using the 295X branding on mobility chips,
we may soon see a better binned Hawaii GPU called the Radeon R9 295X
which may feature boosted clocks compared to 1000 MHz on the Radeon R9
290X. This would be somewhat similar to the Radeon HD 7970 GHz and
Radeon HD 7970 GE editions we saw that were released months after the
launch of Radeon HD 7970 in January 2012.

AMD Radeon R9 M295X Tonga GPU Specs Sheet:

	AMD Radeon R9 M290X	AMD Radeon R9 M295X	AMD Radeon R9 275X	AMD Radeon R9 280X	AMD Radeon R9 290X	AMD Radeon R9 295X
GPU Core	Neptune XT	Tonga	Tonga	Tahiti XT	Hawaii XT	Hawaii XTX
GPU Process	28nm	28nm	28nm	28nm	28nm	28nm
GPU Cores	1280	2048	2048	2048	2816	2816
Core Clock	900 MHz	800 MHz	~800 MHz	1000 MHz	1000 MHz	~1100 MHz
VRAM	4 GB GDDR5	4 GB GDDR5	2-4 GB GDDR5	3 GB GDDR5	4 GB GDDR5	4 GB GDDR5
Memory Clock	1200 MHz	1375 MHz	1375 MHz?	1500 MHz	1250 MHz	~1250 MHz
Memory Bus	256-bit	256-bit	256-bit	384-bit	512-bit	512-bit
Memory Bandwidth	153.6 GB/s	176 GB/s	176 GB/s	288.0 GB/s	320 GB/s	320 GB/s
TMUs / ROPs	80 / 32	128 / 32	128 / 32	128 / 32	176 / 64	176 / 64