GPU "Cores"?

Discussion in 'MacBook Pro' started by macagain, Feb 1, 2009.

  1. macagain macrumors regular

    Jan 1, 2002
    Ok, look into your crystal balls everyone...

    I'm trying to decide whether to upgrade from my gen 1, rev. b mbp (core 2 duo, ati radeon X1600) to the last of the gen 1's (2.6Ghz GeForce 8600m GT) which you can get for a screaming deal (1650).

    I believe I won't really see too much speed diff now (some, but not like "wow!"). But I'm wondering with OpenCL, if the 8600m GT would make a much bigger diff.

    Also, anyone know what is considered a "core" in a GPU? I've read that it's a bit of a stretch to call them cores, as they are nowhere like a CPU core. The 9400m claims to have 16 cores (; is that the same as Stream Processors which the 8600m GT has 32 ( What about the X1600, anyone know how many "cores" that poor thing has?

    Oiy. This marketing gobblegook is really confusing!
  2. Quu macrumors 68020


    Apr 2, 2007
    The X1600 doesn't have any cores. It is before the unified shader architecture that current GPUs have.

    The X1600 has 'pixel pipelines' designed specifically for processing and shading pixels. It is not a GPGPU (General Purpose - Graphics Processing Unit)

    The 9400M the 8600GT and 9600GT however are based on a unified shader archiecture and are made up of many 'cores' it is true these are not cores in the typical CPU sense however they are very similar.

    For example each 'Core' in the GPU has its own dedicated piece of cache (just like Cores on a CPU that have L1 and L2 or even L3 caches for Cores to use by themselves or together in a single cache pool or in most cases both).

    These Shader Units can be used to process very specific information. Today they are used mostly for computing graphics but by using CUDA, Stream or OpenCL you can use these Shader Units to compute C code. Very simple instructions but enough complexity to do things like decoding H.264 video, encoding H.264 extremely fast floating point calculations and other tasks that are basic in principle but require some incredible processing muscle.

    The X1600 as a result does not support OpenCL at all. It does not have Cores it is not a General Processor and cannot compute GPGPU code. It is designed for one thing and one thing only, Graphics. To put it another way the circuitry inside that graphics card was specifically designed to handle On Screen Graphics and like you cant use a Bike as a Plane you cannot use this GPU to run anything other then On Screen Graphics. The chip at the time of release had 12 Pixel Shaders and 5 Vertex Shaders which even when it was released wasn't much. 32 Pixel and 6-12 Vertex was the norm in the High-End back then.
  3. raymondu999 macrumors 65816

    Feb 11, 2008
    Whoa. So are you saying that my dad's 2.33C2D (with X1600) can't get the Parallel Computing benefits of OpenCL?
  4. Quu macrumors 68020


    Apr 2, 2007
    That is exactly what I am saying. It is a shame but OpenCL and GPGPU computing in general is quite a new concept. The first compatible GPU's hit the market in late 2006 (GeForce 8 Series from NVIDIA) and were readily available through 2007 and 2008.
  5. raymondu999 macrumors 65816

    Feb 11, 2008
    Ouch. Thankfully he just recently upgraded to a Rev. B MacBook Air!
  6. Quu macrumors 68020


    Apr 2, 2007
    Wrong thread? :D
  7. S-Man macrumors regular


    Feb 1, 2009
    I'd like to know where you can get a 2.6Ghz for 1650...
  8. macagain thread starter macrumors regular

    Jan 1, 2002
    it's now 1699 from macmall (the extra appleinsider 3% discount expired 1/31)... 1849, 150 mail-in rebate

    BUT, the new 2.4 is avail for 1698 from clubmac (also, 150 mail in rebate),WMCACOMJPRODLINK&wt.mc_id=WMCACOMJPRODLINK

    so, 2.6/8600 or 2.4/9600 with new case? so many decisions...
  9. kgeier82 macrumors 65816

    Feb 18, 2008
    yummmm encoding h.264. Finally over 30fps :)

    that 1698 is after rebate bud.

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