And yet the entirety of Death Squadron couldn't pump out enough power to overcome that one second-hand shield generator the rebel alliance managed to build on Hoth. Death Squadron had a SSD with 2000 turbolasers and 2000 heavy turbolasers...and at least five Imperial class destroyers as well.

I do wonder why the rebels didn't put those things on every ship that could fit them, tbh.

Isn't almost all of this information taken from the expanded universe which Disney declared non-cannon?

But even if it isn't, this makes no sense. If this were actually true then there would not even be a point in building a death star.

Perhaps we can test this with a GC3 mod in the future.  

Apparently each Imperial class star destroyer is the equivalent of a Geth Dreadnaught in scale.  We'll pretend the whole melting the ice moon thing didn't happen.  Soldiers tell tall stories all the time.  

One thing to note about the star wars universe is that while the galactic community in Mass affect has only existed for a few centuries, the star wars universe has existed for literally hundreds of thousands of years. There is barely even any mention of pre-space civilizations in the expanded universe, and the few that are mentioned are considered utterly ancient.

This is actually another problem I have with the expanded universe and also an example of "Scifi writers have no sense of scale". How would it even be possible to guess how a space society that old would even look like? Most likely everybody would have just evolved into space gods like the Vorlons from Babylon 5 or something.

Note that the page linked lists 30 TJ as the energy required to melt the asteroid; 250 TJ is the figure given as the estimate for vaporizing the asteroid and the page suggests that vaporization is likely to have occured. Also note that this figure is not for the Star Destroyer's heavy guns, it is for a 'medium-size bolt' presumably from a medium turbolaser cannon. Furthermore, this is for a single bolt. A battery consists of two or more guns unless we're using very nonstandard terminology and so a single battery's fire would consist of two or more bolts per firing cycle.

I would further note that it is not at all clear that the kinetic barriers of the Mass Effect universe would provide any protection at all against turbolaser fire. Lasers are explicitly not blocked by the kinetic barriers of capital ships in Mass Effect, though Reaper shields apparently are partially effective against them (here, last paragraph of the combat section), and I could not say whether or not turbolasers are sufficiently close to lasers in the manner in which they would interact with Mass Effect's kinetic barriers to render Mass Effect's kinetic barriers similarly useless.

I would also question where your figure of 'constant fire from 22 of its batteries' comes from. If the barriers require only 640 TJ to break and each gun fires a bolt which can deliver a minimum of 30 TJ, then that is one bolt from 22 guns (no more than 11 batteries, unless we're using nonstandard terminology; again, in standard nomenclature, a battery consists of two or more guns), not 22 batteries. Furthermore, the kinetic barrier would need to be restored fully between every firing cycle in order to require 'continuous fire' from the Star Destroyer to break the shield, and this page suggests that the turbolasers firing the medium-length turbolasers have the ability to fire one shot every two seconds. Can the Reapers fully restore their shields every two seconds?

The only estimates I can think of off the top of my head can be found here and here. The first page suggests that 1e20 Joules is a reasonable estimate of the energy required to break an Imperial Star Destroyer's shields and 3e20 Joules is a reasonable estimate of the kinetic energy required to do the same, though the former value is absorbed over ~30 minutes of engagement and the latter is suggested to be absorbed over the course of 1-2 days. The second page suggests that a shield which was probably already depleted to an unknown degree had an instantaneous impact absorption capacity on the order of 5e14 joules, and sites a book (Anakin Skywalker: The Story of Darth Vader) as stating outright that Star Destroyer shields in peak condition are capable of absorbing multimegaton impacts, though I think the book in question is no longer canonical as of whenever it was that Disney threw out the EU.

If you were to assume that all the weapons on the Star Destroyer fire medium-length bolts each capable of delivering 30 TJ, that each Star Destroyer is capable of firing 5 shots per second (time averaged rate of fire against the Tantive IV in A New Hope, though the Star Destroyer int that engagement may not have been employing all its guns to the fullest extent as the objective of that engagement appears to have been to disable the Tantive IV rather than destroy it), that Star Destroyers and Mon Calamari Cruisers such as used at Endor have comparable firepower, and that each Star Destroyer was engaged by one and only one Mon Calamari Cruiser (which directed all 5 of its 30 TJ shots per second at the destroyer), then in order for the Star Destroyers to be able to engage the Mon Calamari Cruisers for ~30 minutes before shields began failing the Star Destroyer's shields must be capable of absorbing at least 2.7e17 joules over 1800 seconds (30 minutes) before failing. Another estimate of the shield power you could make involves the assumption that the Imperial Star Destroyer is a 'balanced' warship (i.e. a warship whose defenses are capable of resisting its own armament). According to Wookieepedia's Imperial-I Star Destroyer page, an Imperial-I Star Destroyer should carry at least 91 turbolaser cannons. If we assume that 40 of these can be brought to bear for the 'resists its own armament' test (and I would suggest that ~50% of the ship's armament being brought to bear against a single target is something akin to a lower bound on the ability of a Star Destroyer to concentrate its weapons on a single target), then using the 30 TJ per bolt figure an Imperial-I Star Destroyer's shields should be capable of absorbing at least 40 30 TJ bolts impacting roughly simultaneously, or about 1.2e15 joules. If we instead use the 250 TJ figure for vaporizing the asteroid, then the Star Destroyer's shields should have an energy capacity of at least 1.0e16 joules.

As far as how well the Star Destroyer can resist the fire of the Reapers, the main weapon of a capital ship type Reaper is stated to have a yield of 132 to 450 kilotons of TNT, or 5.5e14 to 1.9e15 joules (source). If Star Destroyer shields are as effective against kinetic impactors as they are against turbolasers, then using the lower bound for 30 minutes of combat and assuming that Star Wars shields do not recover over time, an Imperial Star Destroyer's shields should be capable of absorbing 142 to 491 shots from the main weapon of a capital ship type Reaper. Using the 30 TJ per bolt figure for turbolaser bolt energy, a Star Destroyer's shields should be capable of absorbing about 1 to 2 shots from the main weapon of a capital ship type Reaper; the 250 TJ per bolt figure for turbolasers would indicate that the Star Destroyer's shields can absorb about 5 to 18 shots from a capital ship type Reaper's main weapon. I would tend to expect that the Star Destroyer's shield capacity is somewhere between the first estimate and the second if the 30 TJ per bolt figure is to be used as the energy carried by a turbolaser blast regardless of the type of turbolaser used and the likelihood that this is less than the actual amount of energy carried by each medium-length turbolaser bolt.

It would appear from the information provided that if we are generous to the Mass Effect Reapers then the Reapers might be able to take down a Star Destroyer's shields in one shot and then destroy the ship with a follow-on shot. If we are less inclined to go with minimal estimates for Star Destroyer shield capacity, things get worse for the Reapers very quickly.

It might be that Death Squadron could do so but that doing so would make it unlikely for anyone to survive the bombardment. Vader's objective at Hoth isn't entirely clear; he wants to destroy the rebel forces, yes, but he also wants to capture Luke and may also want to capture some of the higher-ranking rebels. If the Star Destroyers are capable of a high-accuracy long-range bombardment to destroy the shield generator, hangar bays, and major defensive emplacements, the apparent plan of bombarding the world from outside of the system is not inconsistent with capturing high-value rebels. General Veers' statement that the shield is capable of 'deflecting any bombardment' makes that a questionable interpretation, though it's still possible that there was an implied qualifier on 'any bombardment' of "that allows a reasonable chance of fulfilling the 'capture high-value rebels' objective." General Veers was told to prepare his men for something even before the fleet moved to the Hoth system, Vader is known to be interested in Luke even at that stage of the movie, and later events strongly suggest that the interest is 'capture' rather than 'kill,' which all suggest that the objective of the originally planned orbital bombardment is the disabling of major defenses and the closing off of potential escape routes (destroy hangars, hangar exits, exposed vessels) rather than simple base destruction.

As far as why Rebel warships do not carry shields of the same power, why do you feel that Rebel warships (or, for that matter, Imperial warships) have the necessary power available for that? The Hoth base's power generators are only known to have two major power drains -  the theater shield (and much of the base's power should have been redirected to this, according to dialogue in the movie) and the anti-orbital ion cannon. The Hoth base may also have a much larger power source than an average Rebel (or Imperial) warship; Wookieepedia's page indicates that the theater shield was powered by the reactor out of a Praetor-class battlecruiser according to the old expanded universe material, where a Praetor-class battlecruiser was a ship type about 2.5 times the length of an Imperial Star Destroyer and only about ~30 years old at the time of the Battle of Hoth (it was developed in the "final years of the Old Republic," i.e. around the same time that Imperial Star Destroyers began appearing; it may be a design generation or two older, but probably not much more than that). If this is still canonical, or at least representative of the reactor(s) used in the new canon, the base should have had significantly more power available than most of the Mon Calamari Cruisers and Imperial Star Destroyers; Executor and Home One are the main exceptions (along with a couple unidentified potentially large Mon Calamari cruisers which took part in the Endor engagement), and unlike the base those vessels also need to power a significant number of heavy weapons which may be firing at a significant rate for an extended period of time (the base generator(s) powered only a single heavy weapon which fired infrequent bursts of several shots, though it's difficult to assess whether or not this represents a similar, greater, or lesser demand on the available power). The base may also have been able to make use of higher power levels for notionally similar components due to the superior cooling offered by an atmosphere as opposed to vacuum, though at the power levels apparently involved in Star Wars I doubt this would make too much of a difference.

And yet they are not sufficiently advanced relative to the 'new' players on the field to be effectively invincible. The margin of superiority enjoyed by the Reapers is only such that the capital ship type Reapers can engage ~3 capital ships of the species present in the era in which the game is set. These species have only been capable of interstellar spaceflight via mass relay for ~3000 years at the outside, and a species which should have been ~1000 years behind in technology was able to at least compete with the empire with the biggest military. A guy with a club is still a threat to a guy with an assault rifle (though not in most scenarios that aren't fairly contrived), but both of them are very little threat to a guy in a tank, and the Reapers ought to be the guy in the tank with millions of years to develop while the new players on the field are the guys with the club (really recently arrived at interstellar spaceflight) or rifle (older species capable of interstellar spaceflight). They aren't, and while part of that can be attributed to the accelerated development due to the existence of functional relics, your sciences need to be similarly advanced before you can begin to understand even a functioning relic, and your technology and industry needs to be similarly advanced before you can begin making use of anything you learn from that. This means that as far as ancient civilizations go, Prothean and Reaper technology is fairly low-level stuff; Prothean stuff can be understood well enough by species with in-system spaceflight capability to permit those species to reverse-engineer the relics and apply the technology thus developed with little lead time for improving the existing industrial base and overall technology level, and Reaper tech can be understood well enough by species which are so little advanced beyond the initial 'mass effect' discovery that a species which made the discovery within the past couple decades at the outside is militarily competitive with a species that made the discovery a thousand years earlier and which is allied with at least three other species which made the discovery at a similar point or up to ~2000 years before they did that studies of it produce usable results within a few years. Reapers are furthermore insufficiently advanced beyond these that they are vulnerable to the weapons used by these comparative newcomers even without any of the advances gleaned from study of examples of ~modern Reaper technology (as opposed to the presumably older technology represented by the mass relay network, the Citadel, and the stuff that the Reapers do not cleanse during their purge of the galaxy). Some showing for this group that's been around for millions of years when it's facing groups which have had less time to develop by a factor on the order of a thousand or more.

Your saying so does not make my opinion expert, and I would only call it close to an even fight at the very low end of the power range estimated for a Star Destroyer. If we're talking about a campaign rather than a duel, then Reapers are no match because their FTL system is many orders of magnitude slower than the Star Wars hyperdrive (or, for that matter, the Star Trek warp drive, which itself is so much slower than the Star Wars hyperdrive that even assuming parity in weapons and defense systems the Federation would be screwed) except perhaps between very specific predetermined points.

As far as whether or not Federation-class starships would be capable of facing off against a Star Destroyer, I am rather doubtful. However, as far as I am aware, no Federation-class starships have ever been seen; the only mention of them that I am aware of is in The Search for Spock. Due to the paucity of examples of their capability (as in, there are no examples of the vessel's capabilities of which I am aware), I'll not comment on the Federation-class dreadnought's capabilities aside from saying that the technological capabilities of the United Federation of Planets appear to me to be significantly inferior to those of the Empire, including in weapons and defenses and so I would not expect the Federation-class to be worth much of anything, seeing as it's a TOS-era vessel and thus presumably less powerful than equivalent TNG-era vessels.

I think this could only be solved by a cage match between George Lucas and Gene Roddenberry, but unfortunately that can't and won't happen.

http://www.youtube.com/watch?v=ZaB_G1WNT70&t=0m52s

It was sort of addressed in game by what the Reapers were and how they operated.  They left Mass Effect technology so that everyone else would use it and trap them to a predestined progress in terms of technology.  The Reapers of course know it better and therefore come in and can deal with everyone else.  While everyone else also  find out that this miraculous technology that was left sitting around for them to use was actually just a trap to set them up to be reapered. 

So while the Reapers have been around for an unknown amount of time they haven't needed to advanced because they don't need to nor is it their goal.  Their goal was to  to preserve organic life from AI lifeforms by killing everyone and turning them into machines...which still makes no sense at all.

1e20 for an ISD's shields is completely bogus if where using EU evidence. We've seen proton torpedoes go off in atmosphere and it's arguable if they reach even 10KJ equivalency. We know from the same EU that to knock out all 6 shield facings takes roughly 120 torpedoes. That's only 5.4E15. Even if you fudge the proton torpedoes up some anything north of 16 zeroes is unreasonable. And we've seen ISDII's pound each other for 10's of minutes before going down. So the weapons don't hit that hard.

Official armament of an ISDII from EU is 64 turbolasers and 20 Ion cannons cira ROTJ. They have a bunch of smaller guns as well but they're considered chaff in the wind in a capital engagement.

1. The EU has been tossed out, and was never a particularly reliable resource anyways.

2. The only time that torpedoes have been employed against something which might generously be called a capital ship in the movies, the torpedoes had no apparent effect upon the target, an armed merchant freighter (granted, supposedly one with relatively strong defenses). At no other point in the six live action movies were missiles or torpedoes employed against capital ships when there were other weapons available. This strongly suggests that torpedoes are far from capable of bringing down Star Destroyer shields entirely with a mere 120 torpedoes. Beyond that, Proton Torpedoes and Concussion Missiles are supposedly roughly as powerful as one another; the Victory-class Star Destroyer, supposedly armed with 80 Concussion Missile Launchers, is regarded as a second-class capital ship at best by the same EU writers who write of mere tens of missiles and torpedoes first penetrating the shields of and then gutting Imperial Star Destroyers.

We never once see torpedoes employed en masse against capital ships by any group which has an available alternative, despite the supposed power of the weapons in EU sources. We never once see capital ships which are stated to carry torpedoes as part of their armament employ torpedoes against similarly large vessels (Venator-class Star Destroyers are supposedly armed with torpedoes in addition to their turbolaser armament, though it's a mere four tubes with 16 torpedoes each on a ship over 1.1km long when a 12m ship can carry two torpedo tubes and six torpedoes, according to Wookieepedia; the capital ship instead is primarily armed with turbolasers and laser cannons). We hardly ever see fighters employed as the primary attack units against capital ships, except when capital ships are unavailable for the purpose, yet according to your figure of 120 torpedoes to completely down a Star Destroyer's shields the Rebel fighter force should have been a very dangerous threat to the Imperial fleet at Endor; this is not in evidence. Fighters instead primarily engage other fighters and strafe capital ships occasionally; when they do attack capital ships, they furthermore do not employ torpedoes and instead use their laser cannons, despite these torpedoes supposedly being so powerful that a single torpedo ought to be comparable to many minutes of continuous fire from a capital ship.

In short, the EU writers who made up the figure of 120 torpedoes to down a Star Destroyer's shields are full of shit, and made up the figure so that they could have their starfighter-focused stories which largely focus on independent operations of small groups of fighters engage an iconic Imperial warship from the Star Wars movies without bringing capital ships into the story. Video games are another part of the EU which commit this offense, often having fighter torpedoes and missiles bypass shields and cause enormous amounts of damage to the target despite the utter lack of support in the six live-action movies for missiles and torpedoes having that kind of power.

Did you actually bother reading the linked page? 30 TJ is based on melting the asteroids in ESB, and furthermore is based on melting small asteroids in ESB, not vaporizing them. The vaporization figure is 250 TJ per bolt, and moreover is more likely given the behavior of the asteroid upon being struck.

Furthermore, if you are inclined to throw the movies out the window, what possible source material could you accept? The movies are the most canonical source of information on Star Wars, much like the Star Trek shows and movies are the most canonical source of information on Star Trek and the Mass Effect games are the most canonical source of information on Mass Effect. Throw the movies out the window and you're left with nothing but baseless assumptions.

Numbers from video games are something I would rate beneath even many of the written works in the EU for accuracy. Star Destroyers at Endor clearly began to engage well beyond the 1.6 km mark; you only see warships in such close proximity after the Death Star begins targeting Rebel capital ships and the Rebel fleet closes with the Imperial fleet to make the Death Star less likely to be able to get a clear shot.

Beyond that, if we take literal interpretations of dialogue within the movies to be canonical information (a position not dissimilar to that of those who argue that dialogue in the Star Trek programs is an accurate source of information on the capabilities of Star Trek technology), then the 1.7km engagement range of a Star Destroyer is completely nonsensical. Darth Vader's dialogue in The Empire Strikes Back is clearly indicative of an intention to bombard Hoth from outside the system boundary (the fleet emerged "too close to the system ," not too close to the planet), indicating that the weapons of the ships have sufficient accuracy at that range to bombard a planet from several light-hours at minimum. Furthermore, since Vader clearly desires to capture Luke and since General Veers is ordered to prepare his troops for something prior to the fleet even arriving in system and the rebel shield going up, it is unlikely that this bombardment is an inaccurate blanket bombardment of the planet's surface but rather a targeted bombardment which is intended to destroy power generators, shield generators, hangars, hangar exits, and significant defenses. While this is likely an easier feat than engaging a maneuvering warship, it is unlikely that a maneuvering warship is so much more difficult to hit that the effective combat ranges are reduced from several light hours to a mere ~2 kilometers.

Furthermore, I see no reason whatsoever to accept video game figures if behavior evidenced in the movies is to be thrown out the window. Toss out the most canonical source of information yet accept information from one of the least canonical sources, and one of the sources most likely to bend figures simply to make the game work?

And your evidence for the Reapers being capable of evading turbolaser fire is ... what, exactly?

Your entire position is essentially "I don't like the numbers that come out of analyzing the source material or which are stated to be valid for the source material. I will therefore make up my own canon and ignore everything that doesn't agree with me as well as make up 'facts' to support my case (such as the Reaper ability to evade turbolaser fire)." This position is, simply put, an unreasonable basis for any form of rational analysis. Yes, there are flaws with the source material (for Mass Effect, for Star Trek, and for Star Wars). Yes, not everything in each source makes perfect sense under current real-world physics. However, if you are to compare any two settings, you must accept either the numbers stated for the setting or the numbers which come out of analyzing the source material. You are throwing out the Star Wars movies in favor of the unreliable, questionably canonical material in the EU and in video games which play fast and loose with the numbers to fit game mechanics and to make the game enjoyable, simply because the numbers from those derivative products fits your vision better despite being at best a poor match to the demonstrable capabilities within the setting as shown in the movies.

Joeball: the re-watch the original trilogy again, we see concussion missiles amongst other things used against capital ships at endor by the fighters. one of the execturors shield generators gets taken out that way. 

Also when i said 10KJ for proton torps i meant 10KT. *facepalm*

So you're basically saying Star Destroyers are rather poorly designed? Or their passive defenses are so powerful that fighters on average are not a threat UNTIL the destroyers' shields are stripped away in a capital ship engagement? 

Which raises an interesting idea: a good idea to balance carriers is to make defenses a lot stronger than what the fighters can do.  

Also, make it so that as ship gets damaged during battle, its defenses weaken.