External monitor issue on lenovo l27M-30 ON MACBOOK PRO Mid 2014

pixel pitch on that display is listed as:

0.3114 mm (0.0123 inch)

that looks up to about 81 pixels/inch

MacBook Pro 2013 13-in display is 227 pixels/inch (retina)

15-in 220 pixels/inch (retina)

Punchline: with about 1/3 of the pixels, text cannot possibly be as sharp as the built-in display, and this will be most noticeable in letters with diagonals, such as capital N M Z W K

when I blow up your screenshots BIG in preview, the text on the external display looks fine. The background is showing Moiré patterns that suggest that perhaps the resolution is not set to the natural resolution of the display.

another possibility is that you are using a TV set cable for a display.

HDMI cables you want for HDMI-only Displays (higher resolutions than 720p TV sets) are marked as Certified with an anti-counterfeiting tag and are labeled:

"Premium High Speed HDMI cable" or that + "with Ethernet" --OR--

"Ultra High Speed HDMI cable" or that + "48G"

Cables with No Certification tags are good for your standard 720p TV set, and not much more.

HDMI was invented for HD TV sets. it works great at its original resolution of 720i or 720p. At higher resolutions, it quickly develops issues that are complex to solve, and the cables and adapters required to solve are NOT intuitive.

do you get ANY picture using HDMI ?

if you do, the remaining issue(s) are likely due to internal settings inside the display itself, accessible with its "On-Screen display" functions. The "scaling" setting looks like it could be important.

https://download.lenovo.com/consumer/monitor/lenovo_l27m_30_ug_english.pdf

The display you have is perfectly compatible with your Mac. Compared to the built-in display, it will always be a little 'grainy' because it has fewer pixels per inch.

your 2014 model MacBook Pro 2014 13-in supports multiple external displays:

2nd Display Support: Dual/Mirroring*. 2nd Max. Resolution: 2560x1600 (x2*)

Details:* This model supports a simultaneous maximum resolution up to 2560x1600 on two external displays via Thunderbolt.

Alternately, it can support a single display up to 2560x1600 via Thunderbolt and

a single 1080p display at up to 60 Hz via HDMI.

source:

https://everymac.com/systems/apple/macbook_pro/specs/macbook-pro-core-i5-2.8-13-mid-2014-retina-display-specs.html

<<. mean time I have ordered vga cable to connect to thunder bolt. >>

I really hope you are not serious. Analog VGA would be a step backward.

I laid out exactly what cables are required for HDMI, and you can buy one without breaking the bank:

Monoprice 8K Certified Ultra High Speed HDMI Cable - HDMI 2.1, 8K@60Hz, 48Gbps, CL2 In-Wall Rated, 30AWG, 6ft, Black - Product # 42674 - $7.19

Although the data rates for refreshing the display are the fastest data rates in the computer, the additional processor load of an additional display for most Macs is...

... negligible.

This is because there is a built-in hardware rasterizer/display-generator that fetches an entire screen worth of data as ONE command. Processor intervention is only required once-a-screenful (to set it up for the next screenful) about 60 times a second. That kind of load is makes no difference at all.

The number of displays that can be supported is limited by the number of hardware display-generators built in to your Mac.