A single hour of 1080p60 gameplay recorded at typical OBS defaults can easily land between 10 and 20 GB. Multiply that by a regular recording habit and it's not hard to see why "why is this taking up my whole drive" is one of the most common questions gamers who record run into. Here's what's actually driving that size, and where the realistic savings are.
Bitrate is doing almost all the work
File size is essentially bitrate × duration. A 30-minute clip at 40,000 Kbps and a 30-minute clip at 15,000 Kbps can look nearly identical for a lot of content, but the first one is more than twice the size. High motion — fast camera turns, particle-heavy fights, dense foliage — genuinely benefits from higher bitrate, since low-motion menu screens and static UI barely need any. If your recordings are consistently set to a bitrate sized for the busiest five minutes of your session, you're paying that cost for the other 90% of quieter footage too.
Practical fix: if your encoder supports it, use a variable/quality-based rate control (like CQP or CRF) instead of a flat constant bitrate. This spends more data on complex frames and less on simple ones automatically, instead of applying one number to everything.
Resolution and frame rate compound each other
Going from 1080p60 to 1440p60 isn't a modest bump — it's roughly 1.7x the pixels per frame, and file size scales with it. 4K60 is about 4x the pixels of 1080p60. If you're recording at a resolution or frame rate higher than what you'll actually deliver (say, recording 4K to eventually export a 1080p YouTube clip), you're storing detail you're going to throw away anyway.
Practical fix: record at the resolution and frame rate you actually intend to publish at, unless you specifically need the extra resolution for reframing/cropping room in the edit.
The codec you're recording with matters more than people expect
H.264 (the most common, most compatible codec) needs meaningfully more bitrate than H.265 or AV1 to hit the same visual quality — often 30–50% more. If your hardware encoder supports HEVC (H.265) or AV1 recording and your editing software can handle it, switching can shrink files substantially at equivalent quality. The tradeoff is compatibility: older editors and some platforms still handle H.264 more reliably, so this is worth testing on a short clip before committing your whole recording setup to it.
You're probably keeping more than you need
This one isn't a settings fix — it's a workflow habit. A lot of recording setups default to "record everything, sort it out later," which means hours of unremarkable footage sit on a drive next to the five minutes you actually wanted. Regularly reviewing and deleting full-session recordings once you've pulled the clips you want (or extracted just the audio from a moment worth keeping, without the full video) tends to save far more space than any encoder setting.
Where re-encoding after the fact fits in
If you already have a backlog of oversized recordings, re-encoding them down after the fact with a lower bitrate or a more efficient codec is a legitimate option — but it's a genuine quality/time tradeoff, since re-encoding an already-compressed file stacks a second generation of compression loss on top of the first. It's usually better applied selectively (the clips you're actually keeping long-term) rather than as a blanket pass over an entire archive.
The short version: bitrate and resolution set your ceiling, codec efficiency narrows the gap, and how much footage you actually hang onto decides the rest.