Archlord is pretty bad. But, you played runescape and silkroad, Archlord will be a step up for you. If I were you, I would give it a try, afterall like you said, it's free, so you got nothing to lose. Archlord 2 requires at least a Radeon HD 6950 or GeForce GTX 560 to meet recommended requirements running on high graphics setting, with 1080p resolution.
2 ArchLord Alternatives & Similar Games for Mac OS
1. RuneScape
RuneScape is a 3D Action-Adventure, Massively Multiplayer Online, Role-playing, Fantasy, and browser-based video game developed and published by Jagex. The game takes place in the World of Gielinor, a medieval fantasy realm divided into various kingdoms, Regions, and Cities.
The game provides you with an opportunity to explore the vast, wonderful and fantastic Open World. In the game, each area, and the city consists of various Monsters, Resources, and Quests. The players can select and customize their avatar as they want.
The game does not follow a linear storyline, rather, players can set their goals and objectives. The player can also select to combat against NPC Monsters and quests. To earn experience points, players have to defeat monsters, enemies and their bosses to complete challenging quests, etc. and can use their earned experience points to enhance their character powers.
You can interact with other online players through trading, chatting, and also be able to play mini-games and can take part in various activities. RuneScape offers the best mechanics, addictive and quite engaging gameplay, and excellent graphics.
2. Wartune
Wartune is an Action-Adventure, Strategy, Massively Multiplayer Online Role-playing, Fantasy-based, and Browser-based video game. The game features three character classes, such as Warriors, Mages, and Archers.
The game includes PvP, PvE, Solo, and Co-op events in the game. It offers Crafting System, in which you can craft your necessary things and weapons. You can build your own house and interact with other online players.
Through its customization option, you can select and customize your character as you want. Wartune offers a turn-based combat system and allows you to go on a lot of quests to explore the game world, where you will face a lot of enemies and their bosses, as well as horrible monsters.
During the gameplay, you have to slay beasts to earn experience points and use them for your character’s power, buy upgrades, skills, and abilities to become more powerful. With fantastic and addictive gameplay, a quest-based story and excellent visual, Wartune is a fascinating game to play.
More About ArchLord
ArchLord is an MMORPG and Fantasy-based video game provided by NHN Corporation. It takes place in the 3D fantasy world and proposes a crafting system to enable the player to upgrade his items the way he wants to have.
The player is capable of customizing his monsters, such as skin, carve, and even ransack any killed monster. There are eight different types of classes and three kinds of races available, and the player must choose one of them. Each of these classes contains its unique abilities, skills, and attributes. The prominent four playable classes are available, such as Moon Elves, Humans, Orcs, and DragonScion.
You’re going for distance, so go for speed! 
During the game, the player can make lots of fellows, become a part of several guilds, and even struggle to curve his names into the annals of the history. The game authorizes the player to learn how to master the brutal, demanding, and fast-paced PvP content to gain a victory over others.
The player can engage himself in lots of social experiences by interacting with a large number of surrounding NPCs, objects, and other players from all around the world. ArchLord offers several unique features, such as Enduring Legacy, Enhanced Mechanics, Great Graphics, Diverse Characters, Compelling Soundtracks, Online Community, PvP, and more.