Hardshell Jackets

Let me give you a short answer first. 

Arc'teryx's Beta line products (SL Hybrid, LT, AR and SV) are focused on versatility and all-round use. You can think of: 

• AR (All Round) as the most balanced and hence placed right at the center between these 4 jackets, 
• And the SV (Severe Weather) as the more robust model of AR (also the most robust between all these 4 jackets) - it provides approximately 25% more weather resistance and 25% more durability when compared to the AR. 

But these benefits come at a cost of less packability and heavier {30 grams (1.1 oz)} weight compared to the AR.

You can see this in Arc'teryx's Naming Scheme Page as well - for both "SV" and "AR", as well as "Beta". 

In addition to these differences, SV is also longer: Covers your butt (not an unimportant advantage especially if you aren't wearing any insulated pants) whereas AR reaches mid-butt level. 

Lastly, SV is also baggier: Gives you the option to under layer using thicker and/or more garments than the AR (AR is also baggy - just not as much).

So what's the take-away here? 

If you'll be wearing the jacket during high output activities out in quite extreme weather/circumstances (think severe wind, precipitation, abrasion and/or cold), then Beta SV would probably worth going for. For all the other folks (probably 90% of you?), Beta AR is probably the way to go and SV would most likely be an overkill. 

Now the longer answer:

And now the longest answer...

N80p-X (Beta SV) vs N40r-X & N80p-X (Beta AR)

The numbers 40 and 80 represent the thread mass - usually referred to as denier and indicated as 40D and 80D. The heavier the thread, the stronger it is.

80D is one of the strongest and most expensive most robust fabrics used in Arc'teryx's high quality technical jackets.

Equipping a jacket solely with a 80D fabric will result in robust structure and very weather resistant & durable nature - but also a heavier weight and less pleasant & somehow "stiff" touch compared to lighter fabrics such as 40D.

That's exactly the case for Beta SV which uses 80D fabric.

So why are there two different fabrics (N40r-X & N80p-X) for Beta AR?

Because, like I said before, AR is meant to be the most versatile and well-balanced jacket of all 4 different Beta jackets. 

In order to achieve that, the high wear areas are reinforced using N80p-X: Shoulders, back, forearms and top of the hood. Whereas for all the remaining low wear areas, N40r-X is used. 

By combining two different thread mass where necessary throughout the entire jacket, AR successfully manages to catch a very well balance between weight, packability and price advantages on one side (so called fragile but fast side) and durability and weather-resistance advantages on the other side (so called sturdy but bulky side).

Beta LT, for example, uses 40D throughout the entire jacket. Beta SV uses 80D. These are the jackets with more extreme intended uses compared to the AR.

By combining these two, Beta AR avoids both extremes and offers to be a suitable option for all-rounders like most of us.

Speaking of which, you can check out my Beta LT vs AR comparison here.

What I covered so far makes up almost all the differences between Beta AR and SV, but let's continue.

What about r and p?

First of all, both jackets offer the highest quality Gore-Tex: 3L Pro. This makes the weave (r and p) less important.

• R stands for ripstop, a grid texture where the borders of each square are elevated.
• P stands for plain, where there are no elevated fabrics whatsoever.

So how do they work out in practice?

• Typically, ripstop is expected to cross the pathways of potential tears in the fabric and prevent them from propagating. But in our case Gore-Tex 3L Pro of both jackets is already high quality, so this doesn't cause a noticeable difference to say the least.
• Similarly, plain weave is expected to bead the water more effectively since there aren't any elevated fabrics that block the droplets from sliding. However, in our case, both jackets are DWR coated, so the elevated fabrics doesn't cause a negative impact in water-proofing.

The differences caused by the weave (ripstop vs plain) are really minimal (if not non-existent) especially considering more important stuff like the Gore-Tex type and thread mass (denier).

Breathability

This practically feels the same in both jackets.

Equipped with very robust fabric and strong Gore-Tex, neither of these jackets lean on the breathability side of the equation unlike what some synthetic insulated mid layers such as Arc'teryx Proton LT or Patagonia Nano Air tend to do.

That's why most of what you get for breathability comes from mechanical venting, instead of genuinely breathable membranes. 

This trade-off is actually the case for all the shell jackets, not just Beta SV and AR. A shell is meant to be abrasion and weather resistant first, other things second.

Both jackets come with pit zips (which is a mechanical venting method) so they're the same in breathability - and considering all the other shells out in the market, they're pretty breathable. 

Length

Beta SV is longer than the AR {79.5 cm (31.25 inches) vs 75.5 cm (29.7 inches)}.

Like I said before, this can be more important if you won't be wearing insulated pants - since the SV is lengthy enough to cover your butt whereas AR reaches down to mid-butt level.

Bagginess

Beta AR already offers more than enough room for under layering, but SV offers even more of it.

I'd doubt the ample room you get beneath the AR will come deficient for you when you're using it in non-extreme conditions.

This is another outcome of Arc'teryx's approach to these jackets. AR is intended to be for all-round users and SV is for extreme weather users.

Conclusion

If you're having a hard time deciding, then checking out this post of mine that covers all the Arc'teryx Beta and Zeta Jackets might be helpful for you.

If you think both of these jackets would be too heavy for your specific needs and desires, then I'd recommend you to check out my Beta LT vs AR comparison.

Now if this is you:

• "I really don't need any specific features. I want to stay active during the quite cold winters in my town: A lot of fat biking, outdoor climbing, hiking, skiing, snowboarding etc. I'm looking for a shell jacket I can easily use during all these."

I'd recommend you the Beta AR.

If, on the other hand, you either (1) want something even more durable than the Beta AR, (2) will be hiking in quite severe weather or (3) want something baggier to maximize your under layering options, then Beta SV can be an amazing choice for you.

CAUTION: Beta LT just got revised in Feb 2021, and this review isn't updated yet. 

Let me give you a short answer first: Arc'teryx's Beta line products (SL Hybrid, LT, AR and SV) are focused on versatility and all-round use. You can see this in Arc'teryx's Naming Scheme Page here as well - for both "LT" and "AR", as well as "Beta". 

• AR (All Round) as the most well balanced and hence the center of these 4 jackets,
• And the LT (Lightweight) as the lighter model of AR {345 grams (12.2 oz) vs 455 grams (16 oz)} - with %10-15 breathability, %10-15 weather resistance and %25 durability sacrifices when compared to the AR. 

So what's the take-away here? 

If you're an ultralight traveler/backpacker, then the lighter weight and more packable structure of Beta LT can most likely be a more suitable option for you. For all the other folks (probably 90% of you?), Beta AR is probably the way to go. 

You can see their side-by-side comparison on Arc'teryx's site here. 

Now the longer answer: 

The biggest difference between these jackets is in their different Gore-Tex fabrics.

N40p-X (Beta LT) vs N40r-X & N80p-X (Beta AR)

Let me clear this first: N40r-X & N80p-X of Beta AR aren't used simultaneously throughout the entire face of the jackets.

Instead, the N80p-X is used in high wear areas that are better reinforced: Shoulders, back, forearms and top of the hood.

In order to prevent the weight and price of the jacket going through the roof (N80p-X is very heavy, robust and expensive), N40r-X is used throughout other areas where less durability is more acceptable. 

This is also why Beta AR is the most well-balanced of all Beta jackets because Beta LT is 40D and Beta SV is 80D everywhere (they aren't balanced but rather intended for more niche uses).

Beta LT is equipped with N40p-X everywhere.

So what do the numbers 40 and 80 exactly mean?

If you're unaware, the number after the first letter represents the denier (weight) of the fabric. It's usually referred to as 40D and 80D (denier), etc.

As the denier increases (which is 40 vs 80, in this case) the durability and weather resistance will increase, but the jacket will also end up being heavier, more stiff (and hence less packable) with a less pleasant touch.

You can now see the main difference between Beta LT and AR - but let's continue, more to come.

The letter (p or r) after this number represents the fabric weave. R stands for ripstop, which, unlike plain weave (P), is woven with a grid texture.

This is the only difference between them. And as a result:

• Ripstop weave (Beta AR) is expected to prevent the potential tears from propagating considerably less then the plain weave by blocking their paths with elevated fabrics. 
• Whereas the plain weave (Beta LT) is expected to bead the water droplets better than the ripstop because unlike the ripstop, the pathway of droplets won't be crossed by elevated fabrics.

This outcome kind of makes sense when you think about it in theory, but is minimal (or almost non-existent) in practical gear use.

Because:

• Gore-Tex 3L Pro is already very high quality by itself, so ripstop doesn't really add much to Beta AR's durability in practice.
• Both jackets are already DWR coated, so the plain weave of Beta LT doesn't really cause a noticeable difference in water beading.

So, as you can guess now; the vast, vast majority of the extra %10-15 weather resistance & %25 durability of Beta AR and more packable & lighter structure of Beta LT result from the denier difference (40D vs 80D) - NOT the weave difference (ripstop vs plain).

But what about the %10-15 breathability difference?

Breathability

This one will be much shorter.

LT is much less than the AR because it doesn't offer mechanical venting: LT doesn't come with pit zips, whereas the AR does.

If you haven't used them before, you'll quickly realize that the pit zips are a godsend especially during high output activities since they keep you from overheating very well.

Also consider: Bagginess

...especially if you're planning to under layer these shells with fairly thick and/or multiple garments.

Beta AR is slightly baggier than the LT, so it'll allow for a wider variety of under layering options which, in the end, ultimately makes it more versatile.

Conclusion

If you're having a hard time deciding, then checking out this post of mine that covers all the Arc'teryx Beta and Zeta Jackets might be helpful for you.

If you think none of these jackets would be able provide your desired weather resistance and durability, then I'd recommend you to check out my Beta AR vs SV comparison.

Now if this is you:

• "I really don't need any specific features. I want to stay active during the quite cold winters in my town: A lot of fat biking, outdoor climbing, hiking, skiing, snowboarding etc. I'm looking for a shell jacket I can easily use during all these."

I'd recommend you the Beta AR.

If, on the other hand, you want something much lighter and more packable than the AR, and you can sacrifice some breathability (LT doesn't come with pit zips unlike the AR), durability and weather resistance in return, then the Beta LT would probably be your best bet.