另外單論算力，W7000 (2.4T) &> D500 (2.2T) &> D300 (2T)補充一下網路上對那個顯卡的分析：節選自AnandTech的Mac Pro (Late 2013)評測，詳見：AnandTech | The Mac Pro Review (Late 2013)內容有點長，我梗概一下，就之前關注的熱點問題做一說明：
1. 」The new Mac Pro comes outfitted with a pair of identical Pitcairn, Tahiti LE or Tahiti XT derived FirePro branded GPUs. These are 28nm Graphics Core Next 1.0 based GPUs, so not the absolute latest tech from AMD but the latest of what you』d find carrying a FirePro name.「
Mac Pro (Late 2013) 的顯卡依然基於Pitcairn, Tahiti LE 和 Tahiti XT，和當代的FirePro W Series師出同門，並非是最新的R9系列的專業卡分支，僅僅是換了名字。
2. 定製版的三個型號，具體參數如下，對比於FirePro W Series和Radeon HD 7900 Series的列表我就不做了，有興趣的話可以找一找對比一下。
3. 」Despite the FirePro brand, these GPUs have at least some features in common with their desktop Radeon counterparts. FirePro GPUs ship with ECC memory, however in the case of the FirePro D300/D500/D700, ECC isn』t enabled on the GPU memories. Similarly, CrossFire X isn』t supported by FirePro (instead you get CrossFire Pro) but in the case of the Dx00 cards you do get CrossFire X support under Windows.
Each GPU gets a full PCIe 3.0 x16 interface to the Xeon CPU via a custom high density connector and ribbon cable on the bottom of each GPU card in the Mac Pro. I believe Apple also integrated CrossFire X bridge support over this cable. I"m actually shocked that Apple is using a ribbon cable vs. a rigid connector, someone over there must seriously love ribbon cables.
With two GPUs standard in every Mac Pro configuration, there』s obviously OS support for the configuration. Under Windows, that amounts to basic CrossFire X support. Apple』s Boot Camp drivers ship with CFX support, and you can download the latest Catalyst drivers directly from AMD and enable CFX under Windows as well. I did the latter and found that despite the option being there I couldn』t actually disable CrossFire X under Windows. Disabling CFX would drop power consumption, but I didn"t always see a corresponding decrease in performance.「總結一下就是，a. FirePro D Series和W Series的不同點在於，W Series的W8000/9000是帶ECC的（在我的印象中這個ECC也僅僅是軟ECC，同時請注意W7000是沒有ECC的），但D Series沒有ECC；b. FirePro D Series每個GPU都工作在PCIe 3.0 x16下，沒有縮水，且已經內置了CorssFireX Pro橋；c. 因為b，所以在Windows下你可以很簡單的打開CrossFireX。
4. 」Under OS X the situation is a bit more complicated. There is no system-wide CrossFire X equivalent that will automatically split up rendering tasks across both GPUs. By default, one GPU is setup for display duties while the other is used exclusively for GPU compute workloads. GPUs are notoriously bad at context switching, which can severely limit compute performance if the GPU also has to deal with the rendering workloads associated with display in a modern OS. NVIDIA sought to address a similar problem with their Maximus technology, combining Quadro and Tesla cards into a single system for display and compute.
Due to the nature of the default GPU division under OS X, all games by default will only use a single GPU. It is up to the game developer to recognize and split rendering across both GPUs, which no one is doing at present. Unfortunately firing up two instances of a 3D workload won』t load balance across the two GPUs by default. I ran Unigine Heaven and Valley benchmarks in parallel, unfortunately both were scheduled on the display GPU leaving the compute GPU completely idle.「在OSX下，情況就比較複雜了，因為CrossFireX並沒有得到OSX的支持，沒有成熟的負載均衡機制，默認情況下，一個用於顯示，一個用於計算。而由於這樣的劃分，所有的遊戲只會使用單核的GPU，需要遊戲開發者從開發方面做多GPU的支持，但是現在沒有人在做，AnandTech的小編為此跑了Unigine Heaven 和 Valley 結果都是一個GPU在幹活，一個閑置。（請允許我做一個兵庫北的表情。）最後，AnandTech並沒有帶來Windows下的SPECviewperf等相關測試，反而帶來了遊戲測試，鏈接如下：AnandTech | The Mac Pro Review (Late 2013) 有興趣的你可以看看。
這個報價的數據略有點問題。可能是老報價了。
比如說， 圖表裡 HP Z420的報價貌似是挺早以前的報價（或者是customize 之後的報價? 不確定）。 剛剛查了下HP北美官網： HP Z420 Workstations
