How Many Pixels Can a NovaStar COEX Controller Drive?

Every NovaStar COEX controller has a headline pixel number: 3.9 million for the KU20 and MX20, 6.5 million for the MX30, 9 million for the MX40 Pro and CX40 Pro. But that number is measured at 8-bit and 60 Hz. Change the frame rate or the bit depth and the real capacity changes a lot. This guide explains how COEX load capacity works, so you can size a controller correctly before the job, not on site.

Two limits: the canvas and the ports

A COEX controller's capacity is set by two separate limits, and the lower one wins.

• The canvas is the largest image area the controller can output. Anything outside it stays black. The canvas depends on resolution and frame rate, not on bit depth.
• The port capacity is how many pixels the Ethernet or fiber outputs can carry together. This depends on frame rate, bit depth and the receiving cards you use.

For example, the MX40 Pro's twenty 1G ports could carry more than 9 million pixels at 60 Hz, but its canvas is about 9 million pixels, so 9 million is the real limit.

Canvas size per COEX controller (60 Hz)

The width and height can be traded against each other, as long as the total stays inside the limit.

Frame rate: higher Hz, fewer pixels

Capacity scales with frame rate. Halve the frame rate and you can drive about twice the pixels; double it and you get half. On an MX40 Pro with A10s Pro receiving cards at 8-bit:

This matters most in xR and broadcast, where high frame rates and frame multiplication are common. If the resolution you set is too large for the frame rate, VMP lowers the output frame rate automatically, so always match your source's frame rate to what the screen can actually run.

Bit depth: 10-bit and 12-bit cost capacity

Every extra bit of colour depth means more data per pixel. At 60 Hz, NovaStar's figures show roughly:

• 10-bit: about 25–30% less capacity than 8-bit
• 12-bit: about 50% less capacity than 8-bit

HDR content on a 4K screen usually means 10-bit or more, so plan for the lower figure. Not every combination supports high bit depth at all: the KU20 has no 10/12-bit modes, and the MX20 and MX30 don't run 12-bit with A10s Pro cards.

The formula behind it

If you want to check a design yourself, each output port has to stay under its bandwidth limit:

pixels per port × bit factor × frame rate < port limit

• Bit factor for A10s Pro and NovaStar's 5G cards: 24 (8-bit), 32 (10-bit), 48 (12-bit). For other Armor-series 1G receiving cards: 24 for 8-bit and 48 for both 10-bit and 12-bit.
• Port limit: 0.95 Gbit/s for a 1G port, and about 85–88% of 5 Gbit/s for a 5G port.

Worked example, 1G port, A10s Pro, 8-bit, 60 Hz: 0.95 Gbit/s ÷ (24 × 60) ≈ 660,000 pixels per port. The same calculation for a 5G port gives close to 3 million pixels per port, which is why a CX40 Pro needs only six 5G outputs to drive what an MX40 Pro does with twenty 1G ports.

One more limit: a single port can feed up to 512 receiving cards.

Quick sizing checklist

1. Work out your screen's total pixels (width × height).
2. Decide the frame rate and bit depth you really need. 8-bit 60 Hz is the reference; anything higher reduces capacity.
3. Pick a controller whose canvas fits at that frame rate, then check the per-port load with the formula above.
4. Leave some headroom. A screen that only just fits leaves no room for a later upgrade to 10-bit or a higher frame rate.

For a side-by-side of all seven models, see our NovaStar COEX buyer's guide.

Need help sizing a system?

Send us your screen resolution, frame rate, bit depth and receiving cards, and we'll tell you which COEX controller fits. Pixel Pitchers ships NovaStar from Sweden: order in-stock items by 14:00 CET for same-day UPS Express, with delivery in 1–2 days across the EU and no import duties.

Browse NovaStar COEX controllers →

Source: NovaStar COEX Wiki, Loading Capacity Instructions. Always confirm the final load in VMP for your exact setup.