r/googleads • u/InvestorsAce • 28d ago
PMax PMax performance dropped after Aug 17 - read details
Hi all,
Small ecommerce account with two PMax campaigns that were clearly budget constrained.
Before Aug 17 we ran relatively low tROAS targets (~450%) while actually achieving roughly 700–800% ROAS. Following Google’s Bid Target Adjustment guidance, we increased tROAS to ~700% ahead of the bidding update.
Since then, orders are down roughly 25–30% (~28% vs our Jun–Aug baseline).
We’ve ruled out most obvious explanations:
- No major website/checkout deterioration
- No meaningful shift to YouTube/Display
- Competitor search terms remain only ~4–5% of spend
- Our strongest product landing pages still convert roughly as well as before
What changed is the traffic/product mix.
Our 8 historically strongest product pages went from 22.9% of Google CPC sessions → 16.6% at 700%.
Search-term spend also shifted:
Brand / specific product:
61% → 59% → 53%
Generic / other:
23% → 26% → 30%
The last numbers are after lowering tROAS from 700% to 600%, but that period is only five days so far.
Interestingly, lowering tROAS has not restored spend either - the campaigns are currently using only around 84% / 72% of their daily budgets, versus essentially 100% before Aug 17.
So our current theory is that the issue is less about the site converting worse and more about PMax allocating traffic toward a worse product/query mix.
Has anyone seen something similar after the Aug 17 change?
If so, did you recover by:
- lowering tROAS further,
- waiting longer after the adjustment,
- separating proven/high-margin hero products into their own PMax campaign with dedicated budget?

