It's an old machine. Mainboard is EG50_HC_HR, Gateway brand. Memory modules are micron MT8KTF51264HZ-1G6E1. I'm not mixing different modules. They're both completely identical. Processor is intel B960.Welcome to the forums, newcomer!
Mind sharing a link to the sticks of ram you own? Mainboard's make and model? Processor used on said motherboard? You're also advised not to mix and match sticks of ram, unless you want to deal with troubleshooting, grey hair(or no hair) or sluggish performance from your system.