The question came up when I was planning this beast whether to go with Mega Pulse lasers or Tachyon Beam lasers. Since I'm very new to the laser weapon tree I spent some time looking at the pros and cons and eventually decided on Pulse lasers. This post is to explain why (and to provide content for today since I didn't log in last night at all).
To see the differences, lets take a quick look in EveMON at the basic Mega Pulse Laser I versus the Tachyon Beam Laser I:
Quick math of dividing the damage multiplier by the rate of fire shows that the pulse laser has a bigger DPS and twice as good tracking at the expense of optimal range and falloff. Not to mention Beams are a lot more energy hungry and require more CPU and powergrid to operate.
Now let's look at actual numbers from EFT when fitted to my Nightmare with my gunnery skills and Amarr Battleship IV:
|Multifrequency||Optimal||15 km||33 km|
|Energy / sec||5.3||7.9|
|Standard||Optimal||30 km||66 km|
|Energy / sec||2.9||4.3|
|Radio||Optimal||48 km||105.6 km|
|Energy / sec||4.5||6.7|
The first impression is that Beams are superior due to getting more DPS at similar ranges, for example 188 at 33 km compared to 133 for Pulses at 30 km. But this ignores the extra strain on the capacitor and the fact that the tracking is quite worse. Assuming a target at 30, the pulses can track and hit something moving over 1600 m/s while the Beams are only good up to 675 m/s. Drop down to targets at 10 km, and the Beams are outpaced by something moving 226+ m/s while the pulses are still good up to 548 m/s which is the difference between hitting cruisers and battlecruisers and constantly missing.
I know battleships have drone bays for the close in targets. I lived in a mission running Rail Rokh for a year and am quite aware of how to deal with orbiting ships, but in combination with the extra energy usage and slightly less overall DPS, I'm going go with Pulses for now with the option of switching to Beams later on open to me.