8 monitors taxes the computer resources. Why would you want to do that to your trading machine if you don't have to?
Appropriate tool for the job I suppose. My stuff is all dual CPU with 8-16GB of RAM. I have never had an issue handling multiple monitors no matter what the number. The biggest "tax" on the monitors is the video GPU, memory allocation and PCI/PCI-e BUS throughputs. Most any decent CPU/motherboard combo with a 64-bit OS and a decent amount of RAM can handle 8 monitors just fine. Synergy is a great tool but I would argue that it is just as taxing, both on CPU and network/NIC resources as running a second quad-card on a machine.
at the end, i find separate keyboards and mouse works most efficiently.....no delays, no worries about one PC freezing up, etc etc
Agree. If you have the space or can make it, separate keyboard/mouse is a good way to go. Just divide the multi-tasking load between 2 machines. (Trying to accommodate 2 computers from one keyboard/mouse is just one more thing which can mess up.)