3 ms·
4k and browser composition are non-issue for any PC GPU. It is purely matter of memory bandwidth, and even Broadwell-era iGPUs are fine.
by vetinari 6y ago
4k and browser composition are non-issue for any PC GPU. It is purely matter of memory bandwidth, and even Broadwell-era iGPUs are fine.
- Filligree 6y agoPerhaps it is on Windows. Neither ChromeOS nor my X1 Carbon running Linux have been able to run at 4k without noticeable lag even in the terminal.
- vetinari 6y agoAlso in MacOS. A 2015 13" MBP (which is Broadwell) can drive two 4k displays; the only limitation is, that each of them must be connected to separate TB port. For Linux, I don't know, the only older machine with Linux that I have is Ivy Bridge one, and that is capable only of 4k@30, which is uncomfortable. With Kaby Lake, it's nice. Also, lag is a latency. That would suggest, that your problem is somewhere else, not in the raw GPU performance. GPU itself doesn't have anything with the output resolution anyway, it is handled separate, dedicated block called output encoder.
- swiley 6y agoMost of these modern OSes are doing compositing on the GPU. At 4k you're blitting some pretty enormous surfaces. IMO if you're just going to run a VT and scale everything back up both compositing and 4k cause way more problems than they're worth. Give me tearing, pixels, and unupdated danged regions any day over input latency.
- vetinari 6y agoAt 4K, we are still in the almost 32 MB framebuffer range. At 60 Hz, that's nothing a PC class hardware would have problem with. Mobile GPUs of few years ago, yes, that could be beyond their capabilities, but not iCore Intel GPUs and ddr3 or ddr4 ram. If you are that sensitive to input latency, run your terminal full screen. In full screen mode most compositors skip the compositing step, as there would be nothing to compose with. So in this case, your single, full screen window does direct scan out.