End-user perspective on small office tools & technology

Awaiting a New Laptop

After 6 years with the Lenovo X1 Carbon (Gen 2 circa 2013) I’m seriously considering a new laptop. In truth, the existing X1C still does most of what I need. The display is getting dimmer. The battery life is shorter. It’s short on ports. The 256 GB SSD feels a bit constrained, but it remains a basically functional machine.

My experience has been so good that I would buy another X1 Carbon (Gen 6), but Lenovo has thrown me a curve in the form of the X1 Extreme. It’s an enhanced model that include more; bigger display, more ports, more potent CPU, and most significantly a more capable nVidia GTX GPU. The second generation of the X1 Extreme is about to be released, which has my purchase plans temporarily on hold.

The discrete GPU is a real benefit to anyone who does any kind of live streaming. My favorite tools, vMix and OBS, can both leverage the hardware H264 encoders on a GTX card, offloading a ton of work from the CPU.

A GTX card has one or two available instances of the nvenc hardware. Each may be capable of one or two different “sessions.” In the case of my desktop, with an older GTX 750 TI, this allows the system to encode one way for a live stream (720p30, best case for Facebook for example) while another way (1080p60) for local recording. This is how I approached ClueCon 2018.

Higher-end Quadro or P-Series cards may have more nvenc sessions available.

Yet, I am not a gamer, nor do I produce live streams from a laptop every week. So it’s hard to know if it’s worth spending the premium for the X1 Extreme. That’s more about want than need.

My old X1C sports a modest Intel HD4400 GPU. Intel GPUs target productivity applications, with decent 2D capabilities. They’re incredibly lame at anything involving 3D. This is reflected in the abysmal Passmark score of just 568. Even so, it does have a hardware video encoder known as QuickSync.

The X1C has an i5-3427U CPU with is in the Ivy Bridge range. As such, the QuickSync hardware support H.264 and MPEG-2 encode and decode. This is the hardware that’s leveraged when I enable hardware acceleration in vMix or OBS. I thought it worth trying, to understand just how much this helps the system vs letting the CPU handle the encoding.

I connected a Logitech C922 Pro Stream Webcam to the laptop and fired up vMix. I staged two simple tests; (1) 720p30 and (2) 1080p30.

vMix Project @720p30

  • Logitech C922 webcam at 720p30 (YUY2)
  • Saved to disk as 720p30 MP4 at 20 Mbps H264 (main profile)
  • CPU with hardware acceleration enabled: 27-34%
  • CPU with hardware acceleration disabled: 30-31%
  • No dropped frames in the recording in either case

vMix Project @1080p30

  • Logitech C922 webcam at 1080p30 (MJPEG)
  • Saved to disk as 1080p30 MP4 at 20 Mbps H264 (main profile)
  • CPU with hardware acceleration enabled: 70%
  • CPU with hardware acceleration disabled: 100%
  • Some dropped frames in the recordings.

Quicksync encoding the video clearly helps. Nonetheless, the old X1C is plainly not well suited to handling video in real-time.

I’m once again signed on to produce the live stream from Cluecon. That event, August 5-8, sets the backstop of my wait for the release of the X1 Extreme Gen 2. To get delivery in time, I’ll need to order by mid-July. Also, I’ll pick one of the preset configurations to ensure that it ships same-day.

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