No? Any M5 Max with the upgraded GPU has the full bandwidth, which includes the 48GB model the original poster mentioned. Same as the M4 Max, where only the trimmed part had a lower bandwidth.
Why are you throwing in extra cost for something thats not necessary? I know multiple people with 128GB Macs and none of us upgraded the storage. Especially not on a Studio (which isn't currently available).
I will say that their $3k number is off. I somehow missed that, and its too low.
I made a mistake, there is a $5k config with high memory bandwidth. The Max chip has two tiers (I incorrectly thought the tiers were based on memory capacity), you need the higher tier Max GPU upgrade (+$300) to get the 614 GB/s memory bandwidth but you don't need to upgrade the RAM to 128 GB to get the full memory bandwidth. So to get the 614 GB/s you need to upgrade to the max chip + upgraded GPU, but you can spec it at only 48gb if you want. So the total for an m5 max with 614 GB/s memory bandwidth is $4999-$9999 depending on config.
Still 3x lower memory Bandwidth than a dual 3090 setup which you can build for $3k with parts from facebook marketplace and run in your basement.