Sure would have been nice if you could have gone with a "cool roof" material. If you can't get the ducts out of the attic, and you can't insulate the roof deck, nothing beats a cool roof for reducing attic temperatures.
That said, if you haven't had your a/c serviced for the summer, do it now. If you get it working in tip top shape and it still seems to underperform on hot days, you then know your new roof and/or ridge vent may be the culprit. I'm not all that confident ridge vents reduce attic temps all that much, but they are better than nothing.
Attic temps are mostly driven by the solar heat gain on the roof. The attic temp when it's 90F outside isn't a lot hotter than when it's 85F outside.... probably just 6-7F hotter in the attic. Humidity doesn't drive attic temps.
"cool roof' desings unfortunatly are pretty foreign to most roofers. Plus it's more expensive for the homeowner even though steel roofs last a lot longer and ithe cost difference will pay for itself within probably 10 years... less if you can use tax credits.
By increasing attic air ventilation, it may reduce air temperature, and provide a small heat sink for the ducts and attic floor insulation to dump their surface heat into, but by far the greater heat sink all of this heat WILL migrate toward is the cool interior of your house, and the cool air traveling through the ducts.
In your case, while it may be true your old ridge vent worked better than what you have now, what may be worse is that your new shingles soak up more heat than the old ones did, for whatever reason. You did mention that you went from three tab to architectural shingles. I have no data at the moment to support my notion, but I would be curious to know if there is a difference in the emissivity and reflectivity characteristics between what you had before and what's up there now.
Regardless, get your a/c system serviced and cleaned. You need a reference point to determine which component is at fault; the new roof or the a/c.
one thing I've seen on roofing redoos is changing from gable to ridge... and lack of airflow... soffit vents are where the air enters, ridge is where it exits...
if the house has gable, and ridge is added... the ventilation does not cool the attic...
since you had ridge before, likely this is not the problem, but I thought I'd mention it.
heavier shingles do retain more heat, and more heat has to go somewhere.
After climbing through the attic last night I found the last two rafter bays in the back corner of the house are not insulated, and after checking just now in the heat of the day the drywall on the ceiling feels very warm from below. This is a tiny amount of over all space of the house ceiling (about only 50 square feet at most, and has been this way all along. Hard to describe, but that area of roof in the back corner has an "extension" most of which sits on the real roof and they obviously couldn't get in there to blow insulation. I'll have to see if I can find somebody to do this, maybe go in through the side soffit or something. This is still only a symptom of the bigger problem though - which is either the attic ventilation or the AC.
Attached is the picture I promised. I wonder if those blisters are just copper rust. The effected area is in sunlight all day and directly under the drip eave so it gets rain and night condensation dripping on it. Maybe I should cover it with some insulation?
Please let me know what you guys think, if it is a likely indicator of a Puron leak...
Am I seeing two driers (the blue and the black cylinders on the pipe) in line with one another? If so that might be part of your problem!
No, the black thing you see is just a rubber "seal" I put over the line because the line enters a black poly pipe before it goes under the slab. Since the line is under the drip eave I was concerned it may allow water to run down the line and into the pipe and fill with water over time, so I put a rubber stopper on the line to seal the pipe. It's a rubber foot used for chair legs, simply drilled a hole in the center, slit down the side and put it over the line & pipe.