M73

Processor

 * Intel® Core™ i7-4770S 65W
 * Intel® Core™ i7-4770 84W
 * Intel® Core™ i5-4430S 65W
 * Intel® Core™ i5-4430 84W
 * Intel® Core™ i5-4570S 65W
 * Intel® Core™ i5-4570 84W
 * Intel® Core™ i5-4670S 65W
 * Intel® Core™ i5-4670 84W
 * Intel® Core™ i5-4440S 65W
 * Intel® Core™ i5-4440 84W
 * Intel® Core™ i3-4330 65W
 * Intel® Core™ i3-4130 65W
 * Intel® Pentium™ G3430 65W
 * Intel® Pentium™ G3420 65W
 * Intel® Pentium™ G32203 65W
 * Intel® Celeron G1840T 65W
 * Intel® Celeron G1820T 65W

Operating System

 * Windows 8 Pro 64 bit preinstalled through downgrade rights in Windows 10 Pro
 * Windows 7 Professional 32-bit SP1 preinstalled through downgrade rights in Windows 10 Pro
 * Windows 7 Professional 64-bit SP1 preinstalled through downgrade rights in Windows 10 Pro

I/O (Input/Output) Ports

 * (2) USB 3.0 Rear
 * (2) USB 2.0 Rear
 * (2) USB 2.0 Front
 * (1) VGA output
 * (3) Audio-In / Out / MIC-In
 * (2) PS/2 for Keyboard and Mouse
 * (1) handset
 * (1) Microphone
 * (1) Display Port

Graphics

 * Integrated: Integrated 2013 Intel® HD
 * Discrete: ATI Radeon HD8470
 * Discrete: ATI Radeon HD8570
 * Discrete: NVIDIA GeForce GT620
 * Discrete: NVIDIA Quadro410

Memory

 * 2 DIMM
 * Maximum 16GB up to 1600 MHz

Optical Drive

 * Supported type: Serial-ATA
 * Available drive: DVD-ROM / DVD Recordable

Wireless

 * 2x2 802.11 a/b/g/n with Combo (WLAN+BT)
 * 2x2 802.11 ac/b/g/n Combo (WLAN+BT)
 * 2x2 802.11 b/g/n Combo (WLAN+BT)
 * 1x1 802.11 b/g/n

Storage

 * 3.5" 250GB/500GB/1TB/2TB 7200 rpm SATA
 * 2.5" 64GB/128GB/180GB SSD
 * 2.5" SATA 2.0 320GB 5400 rpm
 * 2.5" Opal SSC HDD 320GB
 * 3.5" 1TB/8GB 7200 rpm SSHD
 * 2.5" 500GB/8GB SSHD

Ethernet

 * Integrated 10M/100M/1000M Gigabit Ethernet

Physical Security

 * Cable Lock / Padlock Loop / Chassis Intrusion Switch / Computrace Support/Kensington Slot

Power Supply

 * 85 Plus 92% Pentium 450W PSU
 * 80Plus 85% 280W PSU
 * 280W Standard PSU

Green Value

 * EPEAT® Gold
 * ENERGY STAR 5.2
 * EL Environment Gold

Software Preloaded

 * Intel AppUp®
 * Nitro PDF
 * Adobe® Acrobat Reader
 * AccuWeather
 * Desktop Power Manager
 * PC Device Stage
 * Evernote®
 * Lenovo Cloud Storage by SugarSync
 * Lenovo Companion
 * Lenovo Settings
 * Lenovo Message Center Plus
 * Lenovo Registration
 * Lenovo QuickLaunch
 * Lenovo QuickSnip
 * Lenovo Solution Center
 * Lenovo Support
 * Norton™ Internet Security 2013 – 30 days trial
 * Security Suite
 * Norton™ Studio
 * Password Manager (Ready-to-Install – Win 7) (Web install – Win 8)
 * Product Recovery
 * Rescue and Recovery® (Ready-to-Install)
 * RapidBoot HDD Accelerator 2.0
 * Skype™
 * ThinkVantage® System Update
 * View Management Utility
 * Cyberlink PowerDVD
 * Cyberlink – PowerDVD Create, Power2Go and Power Producer
 * Cyberlink – PowerDVD Create, Power2Go and Power Producer
 * i-Filter (JP Only)
 * Microsoft® Office 2013 Trial
 * Adobe Acrobat XI – bundled with MS Office Profressional and MS Office Home and Business
 * Adobe Acrobat XI Standard edition
 * Adobe Acrobat XI Professional
 * Adobe Acrobat Lightroom
 * Microsoft Office Professional 2013
 * Microsoft Office Home and Business 2013
 * Microsoft Office Home and Student 2013
 * Microsoft Office Personal 2013 – Japanese
 * Microsoft Office Home and Business 2013 – Japanese
 * Microsoft Office Professional 2013 – Japanese
 * Norton Internet Security
 * Norton AntiVirus
 * McAfee® Internet Security and McAfee® VirusScann Plus

Source
https://www3.lenovo.com/hk/en/desktops-and-all-in-ones/thinkcentre/m-series-tower/10B2/p/11TC1TMM73010B2#tab-tech_specs

http://psref.lenovo.com/syspool/Sys/PDF/ThinkCentre/ThinkCentre%20M73%20Tiny/M73%20Tiny.pdf