Editing Warhammer 40,000/6th Edition Tactics/Necrons (section)

===Troop===
*'''Necron Warriors''' - The closest thing the Necrons have to tarpits and cannon fodder, these guys are basically Cronscripts (get it?). They've lost their 3+ save from the previous codex, gaining a paltry 4+ save instead; on the other hand, they're now much cheaper, so you can field more of them, and they're not the only Troops choice anymore so you don't even have to take them if you don't want to. Just about as good as Space Marines at shooting, and a little cheaper too, but they suffer in close combat, where their I2 and 1 Attack make them worse than Tactical Marines, but still perfectly capable of laying down the hurt on anything weaker than that. Good for parking on an objective or just swamping the field with bodies. And with gauss rules, you can quickly strip an enemy vehicle of it's Hull Points. That's right, your basic troops can once again glance a Land Raider into dust.
*'''Immortals''' - Moved to Troops in the new codex. These guys are basically what Warriors used to be, 3+ save and all, except they cost 1 point less and they have better guns. Start with gauss blasters, can take tesla carbines for free, both options provide nice anti-infantry dakka. Like Warriors, they're still terrible in close combat. But few things are more satisfying than looking at an opposing Tyranid player's face as a few squads of immortals wipe out pretty much all of his gaunts in one turn with Tesla carbine fire.
**Tesla vs. Gauss - One of the biggest decisions around Immortals is whether to field tesla or gauss weapons. Typically, the biggest deciding factor is the tradeoff between rapid-fire and assault weapon types: Gauss immortals will want to stand in place, while a group of Tesla immortals can be expected to either stay outside 12" or fire immediately prior to charging. Mathematically, discounting these two points, the Tesla carbine is equal or superior against all but 4+ armor: (the math still works out in favor of tesla just a slight bump in favor of gauss on 4+ armor then tesla wins again vs MEQ and TEQ)
{| class="mw-collapsible mw-collapsed wikitable"
! Tesla vs Gauss Mathhammer (Expected wounds per shot)
|-
| Armor Value || None || 6+ || 5+ || 4+ || 3+ || 2+ 
|-
| Gauss Blaster || 4/9 || 4/9 || 4/9 || 4/9 || 4/27 || 2/27
|-
| Tesla Carbine || 6/9 || 5/9 || 4/9 || 3/9 || 2/9(6/27) || 1/9(3/27)
|}
**Conclusion: If you know you'll be facing 4+ armor (ork 'ardboys, pretty much anything with warrior in the name (tau fire, necron, most of the aspect kind)), pack your bags with Gauss Blasters.  If not, Tesla Carbines not only won't let you down, but occasionally rock much harder than expected.
**The other issue is that Gauss can glance vehicles. Normally, this isn't a big deal, because you have warriors for that. But if you use an Immortal-only concept army, it might become important. 
**One final note on Tesla vs. Gauss - Necrons are typically the guys that don't worry much about anti-air, given the fantastic Night and Doom Scythes.  However, if you don't want to bring them, triarch stalkers and tesla immortals give one a surprisingly decent AA option.  Considering that one hits only on sixes (three times at that), a twin-linked Tesla carbine delivers an expected 11/12 hits ''per shot'' against a flier.  That's really quite acceptable for smoking flying daemon princes, and while strength 5 won't faze a Heldrake it will at least give you an option against most fliers (AV11).  Gauss guns, on the other hand, could drop a Heldrake or Stormraven, but will expect only 11/36 hits when twin-linked.

*'''A word about resurrection orbs''' - The Necron infantry serves both as a gunline and as a cheap source of tough, gets-up-when-killed wounds.  In order to supplement a 20-man warrior or 10-man immortal squad many commanders slap a Necron Lord in with a res-orb and warscythe to give the squad what essentially amounts to a 4+ FNP and two nasty can-opener swings.  This makes each troop much tougher to grind through with bolters, lasguns, and other light anti-infantry weapons.  However, this isn't always as mathematically sound as it might at first seem.  The lord costs 75 points, and the regular models are pretty inexpensive.  If you do the math, a squad of ten immortals without a res-lord supplies .09362 wounds per point if you account for their reanimation and the extra wound the lord supplies.  Remove the lord, and the army is getting .09375 wounds per point, almost exactly the same value.  Warrior squads benefit more: a lord takes the squad from .1154 wounds per point to .1254, a noteworthy improvement.  The implications are pretty clear, though: if you want to field immortal squads you'd probably do better leaving the res-lords at home and getting an extra few squads.  Of course, sometimes you might want one really tough squad to sit on an objective rather than several weaker ones.  Season to taste.