I'm planning to upgrade my current PC from an RTX 5060 Ti and Intel Core i5-12400F to a GeForce RTX 5090 and Ryzen 7 9800X3D, but I'd like to keep using my Cooler Master Q300L V2 case. The internal clearance looks extremely tight, and I don't want to risk damaging an expensive graphics card during installation or running into poor airflow afterward. Has anyone confirmed whether this combination will physically fit and cool properly?
3 Answers
Even if the card technically fits, the clearance sounds dangerously tight. A high-end graphics card can cost several thousand dollars, so forcing it into a cramped case could scratch the card, stress the connector, or make installation difficult. I’d strongly consider a larger case with more GPU clearance and better airflow.
The Q300L V2 is better suited to lower-power, budget-oriented builds. A 5090-class card will likely produce far more heat than the case airflow setup is comfortable handling, so thermal performance may be poor even if the card fits on paper. Check the exact GPU length, thickness, power-connector clearance, radiator or front-fan space, and the case’s maximum supported dimensions before buying.
The processor upgrade makes sense if you want a new high-end gaming platform, but the i5-12400F is still capable and isn’t automatically a reason to replace the whole system. If you do move to the 9800X3D, treat the case as part of the upgrade rather than trying to squeeze everything into the existing chassis.

I originally chose the 12400F because I was on a tight budget. Now that I can afford it, I’ve wanted to move to a 9800X3D for a while, so I’m considering the full platform upgrade.