If I was to setup a mining machine with quad 750 Ti's powered by a sempron 145, would 4gb of ram be enough to run ccminer efficiently, or would 8gb be needed?
I started out with 4GB and had some problems in Win7 x64, but with some changes to the ccminer it helped a lot when running multiple instances. Since I upgraded to 8GB (6x 750ti) I haven't had any problems at all.
Currently though, when up and running the machine is only using about 2GB.
I don't think it is 'required' right now to have more than 4GB, but honestly I wouldn't want to risk what could happen in the future over what amounts to ~$25 in RAM.
A friend is running Asrock 970 extreme4+AMD sempron 145 with 4Gb ram, running 5x750ti's with up to 3 instances without issues.
Disabled in BIOS all unnecessary devices like (audio, LPT,COM,MIDI,game, IR ports, firewire...etc...) Running win7 x64 with disabled all unnecessary processes like winsat, automatic updates, wiindows defender, etc, etc...