On two 27-inch QHD monitors, the first spec that separates image quality is not resolution but the panel. On published specs, TN rarely clears a 1,000:1 contrast ratio, VA runs above 3,000:1, and OLED is effectively infinite. Nothing else on the sheet varies by a factor of three at identical resolution.
Response time, meanwhile, has all but converged across the three LCD types. What remains are contrast ratio, viewing angle, and the burn-in risk unique to OLED. Convert the spec numbers into black-level brightness and frame time and it becomes clear which line item actually changes what you see.
The three numbers that separate the four panels
BenQ Korea's panel selection guide lays out the three LCD types as follows. On contrast ratio, TN almost never exceeds 1,000:1, VA frequently passes a baseline of 3,000:1, and IPS sits between them. On response time, TN is fastest at under 1ms while VA and IPS land in the 1–2ms range. On viewing angle, TN is narrowest at 170/160 degrees, with VA and IPS both at 178/178.
OLED is built differently, so the basis of comparison shifts. Samsung's OLED monitor guide explains that because each pixel switches off completely, contrast ratio approaches infinity, the Odyssey OLED G6 delivers roughly 0.03ms (GtG) response, and HDR certification covers peak brightness up to 1,000 nits. Power draw runs the other direction — a Korean panel comparison guide classifies TN and VA as low consumption and IPS and OLED as high.
| Panel | Contrast ratio | Response time (ms) | Viewing angle (deg) | Power draw |
|---|---|---|---|---|
| TN | Under 1,000:1 | Under 1 | 170/160 | Low |
| IPS | Between TN and VA | 1–2 | 178/178 | High |
| VA | 3,000:1 and above | 1–2 | 178/178 | Low |
| OLED | Near infinite | 0.03 (GtG) | Very wide | High |
The response time column is the one that catches the eye. Under 1ms for TN against 1–2ms for IPS and VA is a twofold gap on paper, but judging what a 1ms difference does requires converting it into frame time, which comes later. The contrast column, by contrast, is a threefold gap that converts directly into screen brightness.
What does a 3,000:1 contrast ratio mean in actual black level?
Contrast ratio is the ratio of white luminance to black luminance, so black level works out to white luminance ÷ contrast ratio. Holding white luminance at 300 nits — the standard brightness of an office monitor — gives the following black levels.
| Contrast ratio | Where it sits | Black level (nits) | Multiple vs 1,000:1 |
|---|---|---|---|
| 1,000:1 | TN ceiling (per BenQ) | 0.300 | 1.00 |
| 2,000:1 | Between IPS and VA | 0.150 | 0.50 |
| 3,000:1 | VA baseline (per BenQ) | 0.100 | 0.33 |
| 4,000:1 | Upper VA range | 0.075 | 0.25 |
| Infinite | OLED (per Samsung) | 0.000 | 0 |
In absolute terms the gap looks small: 0.300 nits for TN against 0.100 nits for VA is a difference of 0.2 nits. But that number only matters under a condition — once ambient light reflecting off the panel exceeds 0.2 nits, the threefold difference in the table disappears into the reflection. That is why the same monitor looks like a different product in a lit office and in an unlit room at night.
Panel specs are decided at the dark end, not the bright end — 1,000:1 versus 3,000:1 comes down to a black level of 0.300 nits versus 0.100 nits.
OLED's 0.000 nits occupies a special place in this calculation. Pixels switch off rather than dimming a backlight, so black stays at zero whatever white luminance you assume. No amount of contrast-ratio inflation gets an LCD there, which is why panel choice matters most for content weighted toward dark scenes.
How high a refresh rate does 1ms response actually support?
Response time matters relative to how long a single frame stays on screen, not in absolute terms. Frame time is 1,000 ÷ refresh rate. The table below shows frame time by refresh rate and the share of it consumed by different response times.
| Refresh rate (Hz) | Frame time (ms) | 1ms as share (%) | 3ms as share (%) | 5ms as share (%) |
|---|---|---|---|---|
| 60 | 16.67 | 6.0 | 18.0 | 30.0 |
| 144 | 6.94 | 14.4 | 43.2 | 72.0 |
| 240 | 4.17 | 24.0 | 72.0 | 120.0 |
| 360 | 2.78 | 36.0 | 108.0 | 180.0 |
At 60Hz even a 5ms panel uses only 30% of the frame time — the zone where the response-time figure on the box is effectively meaningless. Move to 240Hz and that same 5ms consumes 120% of frame time: the next frame arrives before the pixel finishes its transition, so the panel does not deliver the sharpness the refresh number implies.
Two conclusions follow. First, refresh rate and response time cannot be evaluated separately on a high-refresh monitor — a 360Hz panel with 3ms response is already over budget at 108% of frame time. Second, OLED's 0.03ms is 1.1% of a 360Hz frame, leaving no room for response time to become the bottleneck. How far the refresh rate itself is perceptible is covered separately in the piece on 60Hz versus 144Hz.
What OLED gives up for infinite contrast
OLED's weakness sits outside the numeric spec table. A self-emissive structure brings with it the risk of retained images where static content stays on screen for long stretches. Samsung's guide states that recent models apply mitigation technology, describing OLED Safeguard+ as reducing the risk through a dynamic cooling system that disperses heat five times faster, plus logo detection and a screen saver. That is risk reduction by engineering, which is a different proposition from an LCD that has no burn-in mechanism to begin with.
- 0 nit black level — a range LCDs cannot reach
- 0.03ms (GtG) response — 1.1% of frame time even at 360Hz
- Viewing angle effectively unconstrained
- Burn-in risk under prolonged static content — mitigated, not structurally removed
- Classified in the high power-draw group
- Priced above LCDs of the same size and resolution
The risk grows for work screens where fixed elements — taskbars, toolbars — sit in the same position all day. The exposure conditions under which burn-in actually becomes a problem are broken down by hours in the guide to OLED burn-in conditions. Brightness deserves a check too: Samsung's 1,000 nit figure is peak HDR brightness, and how long full-screen brightness holds is a separate variable in a bright spot near a window.
Who each panel suits, and who should wait
- IPS if colour accuracy and viewing angle set the bar. 178/178 viewing angles and stable colour suit photo and video work where the edges of the screen have to be as trustworthy as the centre. Factor in a contrast ratio that lands between TN and VA.
- VA if dark content dominates. Contrast above 3,000:1 drops black level to 0.1 nits. In a darkened room watching film, this is where VA separates most from IPS.
- TN if budget leads and you stay in the 60–144Hz range. Sub-1ms response is ample there. The 170/160 degree viewing angle turns against you as screen size grows and corner colour shifts.
- OLED if you want high refresh and deep blacks together. 0.03ms leaves headroom even at 360Hz and black is 0 nits. If the use case is a work screen with fixed elements running eight hours a day, check the burn-in conditions first.
- Reasons to wait. If ambient light where the monitor sits is strong enough to swallow a 0.2 nit difference in black level, money spent on contrast ratio does not come back. In that case the same budget goes further on resolution or size.