Mac Pro is optimized for performance. That includes a four-channel DDR3 memory controller running at 1866MHz.
In the history, Pro computers have relied on the CPU for their computing power. As GPU performance has increased, with the Mac Pro Apple's software developers have leveraged that power in their apps. They engineered a very powerful GPU architecture, which features a state-of-the-art AMD FirePro workstation-class GPU, available with 2GB, 3GB or 6GB of dedicated VRAM and up to 2048 stream processors.
You can always sell Mac Pro 2006 - 2013 online to iGotOffer.
The Apple's Mac Pro is muscle through and through, starting with the Intel Xeon E5, available with 4, 6, 8 or 12 cores of processing power. Working with Mac Pro, with its up to 30MB of L3 cache, 40GB/s of PCI Express gen 3 bandwidth and 256-bit-wide floating-point instructions, you never are at a loss for speed.
However, when you you decide to upgrade your desktop and get yourself a new, more powerful model, you can sell your old Mac Pro 2006 - 2013 to iGotOffer for the best price online.