AMD debuts Radeon M400 mobile GPUs with a host of rebrands

We've just noticed that AMD updated its website with a new line-up of laptop Radeon GPUs, the Radeon M400 series. The company hasn't made an official announcement about this line-up, but the specifications on their own are enlightening. Let's start with the R9-class parts in this lineup.

Radeon R9 M400 Series R9 M485X R9 M470X R9 M470
Stream processors 2048 896 768
Texture units 128 56 48
Render output units 32 16 16
Memory capacity up to 8GB GDDR5 up to 4GB GDDR5 up to 4GB GDDR5
Memory bus width 256-bit 128-bit 128-bit
Memory clock up to 5GT/sec up to 6GT/sec up to 6GT/sec
Memory bandwidth ≤160GB/sec ≤96GB/sec ≤96GB/sec

Those numbers look pretty familiar. The R9 M485X appears to be closely related to a previous high-end mobile Radeon, the R9 M390X. That product used the GCN 1.2-based Amethyst GPU—a clock-limited Tonga—in its most-complete incarnation, and we expect the same for the new product. Meanwhile, the two smaller GPUs resemble the R9 M385X and the R9 M380. Given the nomenclature and data at hand, it seems likely they are both based on the GCN 1.1 "Bonaire" silicon dating back to the Radeon HD 7790.

R7 M400 Series R7 M465X R7 M465 R7 M460 R7 M445 R7 M440
Stream processors 512 384 384 320 320
Texture units 32 24 24 20 20
ROPs 16 8? 8? 8? 8?
Memory capacity up to 4GB GDDR5 up to 4GB GDDR5 up to 4GB DDR3 up to 4GB DDR3 up to 4GB DDR3
Memory bus width 128-bit 64 or 128-bit 64-bit 64-bit 64-bit
Memory clock up to 4.5GT/sec up to 4.6GT/sec up to 2GT/sec up to 4GT/sec up to 2GT/sec
Bandwidth ≤72GB/sec ≤73.6GB/sec ≤16GB/sec ≤32GB/sec ≤16GB/sec

The R7 M400 series is less clear-cut. We're guessing the R7 M465X is most likely based on Cape Verde silicon, a GCN 1.0 design first seen in the Radeon HD 7770 over 4 years ago. It isn't a fully-enabled chip, as Cape Verde has 10 compute units versus this part's 8, but barring a completely new design, there's nothing else in the annals of GCN that fits this chip's specs. The rest of the new mobile R7 parts are more difficult to pin down with any certainty, but our best guess is that they are all yet more releases of the venerable Oland (aka Topaz) GPU, also a GCN 1.0 part.

Radeon R5 M400 Series R5 M435 R5 M430 R5 M420
Stream processors 320 320 320
Texture units 20 20 20
Render output units 8? 8? 8?
Memory capacity up to 4GB GDDR5 up to 4GB DDR3 up to 4GB DDR3
Memory bus width 64-bit 64-bit 64-bit
Memory clock up to 4GT/sec up to 2GT/sec up to 2GT/sec
Memory bandwidth ≤32GB/sec ≤16GB/sec ≤16GB/sec

The low-end R5 M400 series are odd beasts. To our eyes, these look like even more Topaz rebadges, but going by the available specifications, there is little to set them apart. Even more confusingly, the R5 M435 appears to be identical to the R7 M445, while the R5 M430 and M420 appear to be identical not only to each other, but to the R7 M440. We can only assume that these parts will eventually be set apart by GPU core clock and final memory configuration.

There's no word on clock rates for the new parts, but that's not the only thing missing from these charts. You, astute TR reader, have no doubt already noticed that the most recent processor in the list is the R9 M485X's Tonga GPU. That GCN 1.2 design debuted in late 2014 aboard the R9 285. Everyone reading this right now is no doubt aware that AMD has plans to unveil GPUs based on 14nm FinFET technology in the coming weeks, and their absence from these charts is conspicuous.

AMD has demonstrated the performance of their new hardware twice already, so we have little reason to doubt that Polaris is coming soon. Some holes have been conveniently left in the R9 400 series for the new hardware too, both above and below the M485X. Let's look forward to Computex and hope AMD fills those holes with some spicy new hardware.

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