Penetration confusion?

Obsidian shard

Spear of the magus

Can someone explain to me which of the two penetration items is better and for what reason would you buy one of the items over the other.

I am confused because I was testing both of the penetration in the jungle on the gold furry and the results where confusing.

I was testing it on AO Kuang.

Now I always thought spear of the magus was better on gods that do ticking damage so I thought the spear would do more damage then the obsidian shard sense his torndados tick damage instead of do damage all at once.

But what I seen was that Obsidian shard was doing like 5 more damage then the spear of the magus?

This confused me because I thought spear of the magus would stack more damage then obsidain shard on ticking damage abilites like tornado.

Also I noticed that when testing items on the gold furry having 2 penetration items makes my damage LESS than if I only had one penetration item and replaced one of the penetration items with more attack power.

___________

This makes me confused now because when I play anubis I always thought the spear would have been better because anubis ticks? But in jungle Ao also ticks damage yet the spear was weaker than obsidian shard???

____________

So I want to know :

In what situations should I use the spear over the obsidian shard or the obsidian shard over the spear.

I usually check what items the other teams buy and thats how I pick my items.

So how do I know which to pick because my results in the jungle just confused the hell out of me now...

Obsidian shard is 33% piercing. Spear, at 2 stacks, is 25+ 20% piercing. The # that 33% is better than 25+20% is around 210. So always, always, always take spear, as you CAN go into negative protections, whereas shard will only really help you against tanks.

also that extra 30 magical power is probly whats causing that extra 5 dmg per tick

so does the spear stack on ticks like ao's tornado? I'm just wondering because I always put the spear on anubis because I thought it would stack with the spear.

Yes. Any spell DAMAGE that occurs, will put a stack on. You only need 2 stacks so it's very easy to max it out.

so obsidian shard is only better when they have what around 3 defense items?|
Because 1 item can give about 75 magical defense?

Right. And that's assuming the ones that give a RIDICULOUS amount of magic defense. So literally obsidian shard only helps you against tanks. You'd rather have spear because it still does just as much (considering they almost never build 3 full magic protection items anyway - they'd have no health of physical protection), and you can send their carries/mages into negative protection, meaning they take MORE damage from spells. Spear is almost always the better choice. Except in Match Of The Day when it's like 5 mages. In normal games, always take spear IMO.

As folks above have stated, Obsidian will do better against those with high defense, spear vs low, but something to keep in mind is that with spear you are DEBUFFING the target's defense... i.e. your whole team does more damage to them.

Combine spear with gem of isolation and essentially anyone hit by your tornado is a sitting duck for your team.