ATI Radeon 4870 OpenCL Benchmark
The actual Mac Pro may sport a Radeon 4870 graphic card. A high-end graphic card that Apple sell for few hundreds bucks, but that is totally bad at OpenCL, a great additionin Snow Leopard 10.6…
There’s OpenCL Benchmark of Radeon 4870, which show it slower than nVidia 9400M IGP (on Mac Mini, Mac Book Air, …).
Why radeon 4xxx are so slow? They lack “shared memory” that is the equivalent on a graphic card GPU of a processor cache, so every access to memory is 20X to 30X slower than access to cache (or “shared memory” in this case) and it could not compete even if it’s a 400$ graphic card!
If Radeon 4870 could not compete with GeForce 9400M, how a Radeon 4670 will? Having 4X slower memory and 3X less computing power, the Radeon 4670 will be crushed by GeForce 9400M, not talking about GeForce GT120 or even GT130 of last generation iMac!
Even high-end iMac with Radeon 4850 (0.8X slower than 4870 GPU with 2X slower memory) won’t be able to compete with entry-level iMac! It’s sad!