Roundup: The best external monitor alternatives to Apple's outdated Thunderbolt Display

Initially announced in July 2011, Apple's current 27-inch Thunderbolt Display debuted as the world's first Thunderbolt-equipped monitor, replacing the outgoing LED Cinema Display.

At the time, the Thunderbolt Display offered cutting-edge display technology, borrowing its 2,560-pixel-by-1,440-pixel WQHD IPS screen from the 27-inch iMac that launched a couple months earlier, but it has since been overtaken by higher-resolution options or products that offer similar features at cheaper prices.

Rumblings of a Thunderbolt Display update have circulated for quite some time, but Apple recently set the rumor mill on fire with the stunning iMac with 5K Retina display.

It was speculated that the 5K iMac itself could be used as an external monitor, but those theories are easily swept aside with a quick reference to Thunderbolt's bandwidth limitations. While the new DisplayPort 1.3 standard rolls in support for 5K displays, that functionality is absent in Thunderbolt 2, let alone the original Thunderbolt protocol used by the Thunderbolt Display.

Even Apple recognizes consumer need for more advanced technologies, as seen with the Sharp 4K monitor advertised alongside the top-tier Mac Pro desktop.

At this point, it seems Apple will wait on 5K or higher screen tech backed by a next-gen Thunderbolt revision with DisplayPort 1.3. Until that day comes, here are a few options for Mac owners who need the cutting-edge of monitor technology or simply want an affordable method of expanding screen real estate.

Dell UltraSharp 27 Ultra HD 5K monitor

Dell's lineup of UltraSharp monitors are some of the best deals on the market, marrying solid technology with low prices. The 27-inch UltraSharp is no exception and is perhaps the closest analog to a theoretical 5K Thunderbolt Display made by Apple.

Using a dual DisplayPort setup, Dell's UltraSharp spits out 5,120 pixels-by-2,880 pixels at 60 Hz, while a single cable saves one DisplayPort input, but knocks resolution down to 3,840 pixels-by-2,160 pixels at 60Hz. LED backlighting is impressively bright at 350 cd/m², just under the Thunderbolt Display's 375 cd/m² specification.

In addition, Dell also sells an X-Rite i1Display Pro colorimeter that, when combined with an onboard 12-bit user-accessible 3D lookup table, offers an option for precise color control. Advanced colorimetry settings are usually reserved for more expensive commercial displays.

The Dell 27-inch UltraSharp UP2715K sells for $2,122.67 from Amazon.com, 2,279.99 from B&H Photo, or for $2,499.99 direct from Dell.

Dell also sells a number of cheaper options for those looking for a large 27-inch monitor, including the P2715Q, an affordable 4K display slated to hit store shelves in February for $689.99 from Amazon, or $699.99 from Dell and B&H Photo. The new U2715H offers a resolution identical to the Thunderbolt Display at a more affordable $570.

LG 27-inch ColorPrime IPS Monitor

Those searching for an updated Thunderbolt Display may not need to further than LG's commercial class 27MB85R-B, which also sports a WQHD display with IPS technology. LG is a known to be at least one of Apple's LCD panel suppliers for the Thunderbolt Display and the ColorPrime boasts identical specifications, aside from an anti-glare coating.

Unlike other monitors in its class, the LG boasts Dual-Link DVI-D, HDMI, DisplayPort and mini DisplayPort connections. LG's ColorPrime feature includes Scaler and True Color Pro software that works in tandem with an included calibrator for greater accuracy.

In essence, the 27-inch ColorPrime is the next-generation Thunderbolt Display Apple never built. It can be purchased for for $597.99 from B&H Photo. A second model, dubbed the ColorPrime 27MB85Z-B, tack on two Thunderbolt 2 ports at a cost of $829 from Amazon.

Asus

Taiwanese computer giant Asus also has a good selection of standalone displays in the 27-inch range, including a new 28-inch 4K product dubbed the PB287Q. The 3,840 pixel-by-2,160 pixel resolution panel runs at 60Hz over DisplayPort 1.2, making for clean, judder-free scrolling often associated with lower refresh rates.

The PB287Q comes with HDMI 1.4, HDMI/MHL 1.4 and DisplayPort inputs covering a wide gamut of connectivity alternatives, including all modern Mac products. Asus applies in-house processing technologies like SplendidPlus and VividPixel to boost color accuracy and image sharpness, while a highly adjustable stand can be raised 150 millimeters, swivel 60 degrees in either direction or pivot 90 degrees for portrait-style operation.

Despite a formidable feature set, Asus' PB287Q comes in at $593 from Amazon.

In the 27-inch WQHD class, Asus' PB278Q is LED-backlit like Apple's Thunderbolt Display and incorporates HDMI 1.4, DisplayPort 1.2 and Dual-link DVI connectivity. This slightly smaller model does not feature an IPS panel, but does come in at $479 from both Amazon and B&H Photo, much lower than competing products.

Sharp 4K monitors

Stepping up to a 32-inch monitor, Sharp's PN-K321 was one of the first professional-grade 4K displays on the market and still comes in near the top of the pile in terms of image quality. The display employs a high-efficiency IGZO panel to achieve impressive color accuracy and brightness, especially for its huge 32-inch form factor.

While no longer tops in terms of outright resolution at 3,840 pixels-by-2,160 pixels over DisplayPort, the PN-K321's huge screen size and great visual performance make it one of the best displays out there.

Sharp also has a touchscreen version in the PN-K322B, which includes a tilt stand for easy touch access and its own Mac touch panel driver software for use with OS X.

The Sharp PN-K321 is on sale at a new low price of $2,962, while the touchscreen PN-K322B comes in at $4,017, both through B&H Photo.

It should be noted that many leading manufacturers are content to employ DisplayPort or mini DisplayPort technology in place of Thunderbolt, meaning their products can't be used as docking stations for other Thunderbolt-equipped devices. For that, Apple's Thunderbolt Display remains the best option.