I have a HP Slimline 290 which has a G4900 processor, it shows on the upgrade list G5400 as compatible.
My motherboard is Menlo by HP Intel H370 Chipset.
The official HP compatible upgrades are:
I was going to buy the G5400 processor but while searching I noticed an almost identical but slightly faster G5420 that is 1 year newer for only a few dollars more.
I did find a newer HP Slimline 290-p0112d which also has the same motherboard as my HP Slimline 290-p0043w called MENLO, and the p0112d has the G5420 in it.
My question is since my desktop is compatible with the G5400 will the G5420 work as well?.
Also other then the slightly faster clock speed is there any other difference between the G5400 and G5420?
If the processor is not on HP's list, then you need to ask HP if their board's bios supports the G5420. A processor must be socket, chipset, AND BIOS COMPATIBLE.
You can compare the two processors here: