Dell precision 690 cpu upgrade

hello, i have an old dell precision 690 and i wish to upgrade the cpu.

i have intel xeon 5130.

as far as i know, im only copitable with 51xx series and 53xx.

i compared the 5160 to others 53xx models and i was quite surprise that it got a higher score on cpuboss.com that sounds weird for me, the 53xx have 4 cores..

another question is if its possible to have 1 cpu 5160 and another cpu 5130 on the same board?

i would like to hear your opinion. thanks!