As far as I know computers like that only have one GPU (Graphics Card) as the maximum.
I just asked about using a Personal Computer for mining and was told that it is definitely not worthwhile under any circumstance.
https://bitcointalk.org/index.php?topic=2415854.0
You are better off purchasing something like a ASIC Bitcoin Miner machine.
"Since it’s now impossible to profitably mine Bitcoin with your computer, you’ll need specialized hardware called ASICs."
https://www.buybitcoinworldwide.com/mining/hardware/