No... It is
THE cause...
If you go over the amount of VRAM, the PS2 has to continually send the
cached texture (already free from any storage-device bottleneck) from EE-RAM to VRAM and it would need to do that:
- 180 times (3-pass VMode at 60Hz) at 1920x1080 at/times x-Bitdepth (11390,625MBit/s = 11,124GBit/s) + RAW texture sizes 180x/s vs.
- 180 times at 1280x720 at/times x-Bitdepth (5062,5MBit/s = 4,95GBit/s) + RAW texture sizes 180x/s
...within one second, which
the bus from EE-RAM to VRAM can not handle fast enough (at least not via gskit and the current implementation of rendering)!
We already know that and have proven it in 2018 and some of the tests are even on video on my channel AFAIR.
What you claim is simply wrong and we KNOW what the cause is. But I digress... You will endlessly argue it, regardless how many people will tell you that.
tl;dr The BUS between the EE-RAM and the GS is the "bottleneck", NOT the bandwidth of the "storage-device" of the ART!
...and it is "triggered" by too much VRAM usage (which actually works to a certain degree, i.e. like 30% more than we actually have, before glitching).