Canadian prices are honestly so painful rn. Before I throw out some cheaper alternatives, what exact case are you working with? Just need to know clearance so we arent suggesting something thats too long for your basement. For what its worth, picking up something like the Corsair RM850e ATX 3.0 usually goes on sale way cheaper than the standard models up here and saves you from using those sketchy adapters.

Canadian hardware pricing is honestly brutal lately, so I totally feel your pain on the budget front. Building a system with a AMD Ryzen 7 7800X3D and an RTX 4070 Ti Super means you definitely want proper ATX 3.0 protection without draining your bank account completely. Here are a few solid options floating around right now that fit what you need:

• Corsair RM850e ATX 3.0
• Usually hits right around that $150 to $170 CAD sweet spot, gives you native 12VHPWR, and fits most standard cases easily. Just keep in mind some folks complain the fan can get slightly louder under heavy loads compared to the older RMx units.
• MSI MAG A850GL PCIE5
• Often priced slightly cheaper than the Corsair units in Canada, fully modular, and includes the 12VHPWR cable with the clever yellow connector so you can instantly see if it's plugged in all the way.
• be quiet! Pure Power 12 M 850W
• Super quiet operation and rock-solid voltage regulation. Usually right in the $160 range and checks every single box for ATX 3.0. Personally, I ran into a similar paranoia spike with transient loads on my own current setup. Honestly, any of these will give you that 850W headroom and save you from dealing with those sketchy Nvidia adapter cables. Just hunt for whatever is on sale this week since Canadian pricing fluctuates constantly.

Canadian prices are brutal right now, ngl. I actually went through the exact same headache when I built my rig with the 7800X3D and a beefy card. Looked at the RM850x originally too, but unfortunately it lacks that native ATX 3.0 support and native 12VHPWR cable you are stressing about. I grabbed an ATX 3.0 unit from another brand instead, thinking it would solve all my transient spike paranoia. Turns out the fan profile on the one I got is way louder than expected under load, which was super annoying after spending so much cash. Honestly, if you want peace of mind without those stupid adapters, make sure whatever you pick has the updated connector natively, just watch out for noisy fan controllers on some of the newer models.

^ This. Also, omg I have this exact same issue with my build... been stressing over Canadian pricing for weeks now and still cant decide on a unit tbh.