Q: Editing 4k with FCPX... Time line fractioned and very slow

Can anyone help.

I understand that I should buy a new iMac to be able to edit 4K. Apparently my graphics card is not powerful enough..... Right now, I cannot afford a new iMac.

Can anyone suggest tips as to how can I edit two projects with what I have got???

I recently bought a new 4TB external hard drive to be able to edit these two projects. Each project is over one hour.

I have already created two new libraries that take about 1.5 TB... leaving 2.5TB free.... I gather it should be enough to do the editing?

Well the time line continues to jump and break and I have tried deleting caches, cleared preferences and move practically everything away from the computer´s hard drive.

I have 219 GB free which should be enough...