90mm. That is more than a KV-2 derp HE and more than any of the T49's rounds (gold or not).
Combine this with the fact that HE rounds do 330 damage on average (compared to 250 for the AP rounds) and you have a little anti-light beast.
I've taken to loading HE as the primary and actively looking for places where I can use the 90mm pen. With 90mm you can not only get full-pen shots on most light tanks and tank destroyers, but on a surprising number of mediums too – and 90mm is enough to go straight through the side of most tier 8 and even tier 9 heavies! For example, the Lowe has flat 80mm side armor, American heavies all have ridiculously light armor on the sides and rear…even the IS-3 has 90mm of effective armor if you shoot it right in the butt. So if you can flank heavies in the Schwarzpanzer you can dish out 330 damage and run away laughing while they try to figure out what the heck just happened.
Just today I rolled 415 on a T29 who got a little too excited poking around the corner…oh, the laughs. Nobody excepts a "Schwarzawhat?" to be rekking them that much.