Datasheet figures next to each other, and the airflow balance, pressure verdict and case air heating that the fans in each box compute to behind that case's own front. Calculated with the CaseFlow model, not measured.
| Thermaltake The Tower 250 Butter Caramel | Thermaltake The Tower 250 Hydrangea Blue Mini Tower Chassis | |
|---|---|---|
| Form | Mini Tower | Mini ITX |
| Volume | 42.7 L | 42.7 L |
| Dimensions | 506 × 300 × 281 mm | 506 × 300 × 281 mm |
| Front | glass solid or glass front | glass solid or glass front |
| Fan mounts | top 2 × 120, rear 2 × 120/140, side 3 × 120/140 | top 2 × 120, rear 2 × 120/140, side 3 × 120/140 |
| Radiator support | side 360 mm | side 360 mm |
| Dust filters | top, side, bottom | top, rear, side, bottom |
| GPU length | 360 mm | 360 mm |
| Cooler height | 210 mm | 210 mm |
| Stock fans | 2 × CT120 (top) | 2 × CT120 (top) |
| Stock airflow, max rpm | 0 in / 100 out CFM | 0 in / 100 out CFM |
| Stock pressure verdict | negative: mid -100.3 CFM | negative: mid -100.3 CFM |
| Case air at 290 W | +5.3 K | +5.3 K |
| Stock fan noise | 28.9 dB(A) | 28.9 dB(A) |
| All mounts, reference fans | 176 in / 238 out CFM 3 / 4 mounts | 176 in / 238 out CFM 3 / 4 mounts |
Both are close enough that the choice is not an airflow question. The pressure verdict describes the stock fan set, not the case: stronger or extra intake fans in the free mounts, or slower exhaust fans, turn a negative balance positive.
Each stock fan contributes CFMmax · derate · rpm/rpmmax behind its wall's mounting class: filtered mesh
front and side mounts as dust filter, bottom as floor + filter, top and rear as open grille, solid and glass fronts as side-slit intake at
roughly half of a mesh front. Front, bottom and side blow in; top and rear blow out.
| Mounting | Airflow blades | Pressure-optimized |
|---|---|---|
| Open grille | 0.88 (0.80–0.95) | 0.88 (0.80–0.95) |
| Dust filter | 0.70 (0.60–0.80) | 0.78 (0.70–0.86) |
| Floor + filter | 0.64 (0.52–0.74) | 0.72 (0.62–0.80) |
| Solid or glass front | 0.50 (0.40–0.62) | 0.58 (0.48–0.68) |
Worst case sums intake at the low end of each band and exhaust at the high end; positive there means positive regardless of how the estimates fall. Case air: ΔT = 3.1 · W / throughput (m³/h), with an open-cooler GPU putting its full board power into the case air plus board, RAM and drives. Capacity puts a reference pressure-optimized fan on every mount at max rpm — 120 mm 60 CFM, 140 mm 75 CFM — a generic good fan, not a product.
Mount counts, radiator support and clearances are datasheet figures. Nothing here is measured; the same model runs in CaseFlow.