Which ATI card(s) do you have?

I would suggest a fresh install rather than an upgrade to 10.10.

During a reinstall, you will be asked whether you want to overwrite the existing operating system or install beside it.

my 980x has 12 gigs but i only see 8 when i dial up beyond 1833 mhz

1 chip is less integrally situated than the other(s)

chips are sold on a heat rating, some like mine won't go far from the reference before POST failure.

In researching this found a reference to "cputime" Linux app and installed it and low behold, it's able to control the amount of CPU time given to a specific PID, a crude form of what Threadmaster GUI can do for windows crunchers on a per science application basis. Regrettably, even when the parent was assigned the lower %, the child-processes did not inherit the % **, else with some scripting it might have worked to set CEP2 to a lower rate and then the disk IO maybe better able to keep up :>)

Anyway found on review that DDDT2+CEP2 allowed latter to achieve 98%+ at full throttle, so no need to restrain at "one at the time" profile setting on my 4+ year old clunker.

edit: ** practically it would have to be set with each of the 16 jobs in a CEP2 task.

Get ahold of Ubuntu Tweak, but think there's more ways to skin that cat. You decide which one you'd like to keep... which I wait to do until happy that CEP2 remains to run fine. Compared to a Windows install, the Ubuntu's are peanuts in disk space. Then use Grub Customizer or BURG to spice up that boot up menu.