I'm considering replacing my aging Intel i5-4690 with an i7-4790K, which appears to be the fastest practical upgrade for my ASUS H81M-PLUS without replacing the motherboard. Since both processors were released around the same time, I'm unsure whether a BIOS update is still required for compatibility. I've never updated a BIOS before, so I'd also appreciate advice on how to check my current version and what steps are involved. The motherboard's battery also seems to have failed, and I plan to replace it at the same time.
3 Answers
Before buying the 4790K, compare used prices carefully. The performance improvement may not justify the cost for such an old platform, and selling the motherboard, CPU, and memory toward a newer budget system could be better value. If you do upgrade, make sure the BIOS supports the chip first.
Check ASUS’s CPU support list for the H81M-PLUS. The i7-4790K requires BIOS version 2001 or newer. You can see your current BIOS version in the BIOS setup screen or in your operating system’s system information. A CR2032 coin-cell battery is the correct replacement for the motherboard battery.
You probably don’t need to update anything if your current BIOS is already new enough. Updating just for maintenance is optional, but there’s no reason to do it before the upgrade if the required version is already installed.

I checked and I’m already running BIOS version 2110, so it looks like the processor is supported. Thanks for pointing me in the right direction!