Earlier this week Apple announced their 2015 15” Retina MacBook Pro. Though Apple didn’t make any CPU changes, they did make some GPU changes on the high-end model, swapping out NVIDIA’s GeForce GT 750M for AMD’s Radeon R9 M370X. Since the M370X was not a published part number in AMD’s recently-announced 2015 Radeon M300 series refresh lineup, there have been some questions over just what M370X really is.

At the time of the rMBP’s launch, we suspected that it was an AMD Cape Verde GPU, based on the fact that this GPU is also in the M375, which is the next part above M370X. With the new laptop shipping immediately, M370X models have already begun arriving in buyers’ hands, finally giving us a chance to confirm the GPU inside.


Image courtesy Reddit user ootan

Thanks to Reddit user ootan, who posted a screenshot of the rMBP’s System Profiler, we can now confirm that the GPU in the rMBP is in fact AMD’s Cape Verde GPU. AMD has previously used the 6821 device ID on other mobile Cape Verde parts, so 6821 is already a known quantity.

AMD M300 Series GPU Specification Comparison
  R9 M375 R9 M370X (rMBP) R7 M360
Was Variant of R9 M270/M260 Variant of R9 M270X Variant of R7 M270/M260
Stream Processors 640 640 384
Texture Units 40 40 24
ROPs 16 16 4?
Boost Clock <=1015MHz 800MHz <=1015MHz
Memory Clock 2.2GHz DDR3 4.5GHz GDDR5 2GHz DDR3
Memory Bus Width 128-bit 128-bit 64-bit
VRAM <=4GB 2GB <=4GB
GPU Cape Verde Cape Verde Oland/Topaz
Manufacturing Process TSMC 28nm TSMC 28nm TSMC 28nm
Architecture GCN 1.0 GCN 1.0 GCN 1.0

As for Cape Verde itself, as our regular readers may already know, it’s one of AMD’s first-generation GCN 1.0 GPUs, launched back in 2012. Compared to the GK107 GPU found in the GT 750M, it is a larger, more powerful (and at least in the desktop, more power-hungry) GPU, designed for more powerful devices than GK107 was. As for why Apple opted to switch now and to this GPU, we’ll leave that to Apple, AMD, and NVIDIA, though it’s by no means surprising that after having run GK107 for a couple of years, they would want to upgrade to a more powerful GPU.

Meanwhile, though we don’t have M370X on-hand at the moment, at least in the desktop, where GPU performance is unrestricted by thermals, Cape Verde fares very well. The rMBP on the other hand does have thermal constraints to deal with, so performance won’t be the same, but I expect it to fare reasonably well as well. Though at the same time I’m also curious if the use of a higher performance part has impacted the rMBP’s battery life when the dGPU is active; AMD and NVIDIA both do heavy binning, so a simple extrapolation won’t work here.

Update: And no sooner do I post this then someone sends me a screenshot of GPU-Z from a 15" rMBP running Boot Camp.

GPU-Z, for those unfamiliar with it, uses register poking to identify GPUs, so if the device ID wasn't enough, this settles it. This also confirms the clockspeeds - 800MHz core, 4.5GHz VRAM - and that the M370X is using GDDR5, unlike it's M375 counterpart. Thank you DMDrew812.

Source: Reddit User ootan (via SH SOTN)

POST A COMMENT

109 Comments

View All Comments

  • Zarniw00p - Sunday, May 24, 2015 - link

    So, M370X is actually part of AMD's Solar System chips, and they support GNC 1.1. Reply
  • Ryan Smith - Sunday, May 24, 2015 - link

    Unfortunately not. Solar Systems are not all GCN 1.1, there are a number of GCN 1.0 rebrands in there (like Cape Verde) Reply
  • Zarniw00p - Monday, May 25, 2015 - link

    http://developer.amd.com/tools-and-sdks/opencl-zon...

    At least AMD promises openCL 2.0 support for 8800M series.. and it requires to my knowledge GCN 1.1.
    Reply
  • tipoo - Sunday, May 24, 2015 - link

    Cinebench R15 – OpenGL 64Bit:
    ~ GTX 850M : ~80fps
    ~ GT 750M : ~65fps
    ~ R9 M370X : ~60fps

    The M370X is not only inferior on OpenGL to the 850M but also to the old 750M …
    Reply
  • Laxaa - Monday, May 25, 2015 - link

    Looking forward to HBM on mobile. It would be interesting to see in a couple of years what performance we could get out of a 14nm GPU with HBM2. Reply
  • hanngman - Monday, May 25, 2015 - link

    Maybe apple wonna refresh 27" cinema display, and GCN chips support 5K resolution opposite to Maxwell? Reply
  • daerron - Tuesday, May 26, 2015 - link

    Strange decision, can only imagine it being made for financial reasons. Would have thought that power efficiency vs performance would be the most important consideration, something that AMD have been struggling with lately, but apparently not. My rMBP 15" already sounds like a hair dryer when playing games on it with the 750M. Reply
  • nutral - Tuesday, May 26, 2015 - link

    Looking at something like 3dmark 11 P, the 950M gets 4500, the 8870/m270 gets 3000 and the 750m 2500. The could have clearly went for the 950 in terms of performance, opencl is probably a bit closer but then still the 950m is faster.
    This probably has something to do with apple going for amd with their imac as well, to keep amd "in" the game and negotiate a bit better with nvidia next time.
    Reply
  • Kaos Sverige - Wednesday, May 27, 2015 - link

    Yeah, its slow http://barefeats.com/rmbp15.html
    NOT REALLY.
    But lets curse Apple before anyone can actually do some proper testing. Now, where are the proper AnandTech tests?
    Reply

Log in

Don't have an account? Sign up now