H3 Flow vs H5 Flow: Micro-ATX or ATX?

The H3 Flow is NZXT's micro-ATX case and the H5 Flow is its compact ATX mid-tower. Both are high-airflow cases with 2-year warranties. The choice comes down to your motherboard size, your GPU length, and how much cooling you plan to run.

Short answer: pick the H3 Flow if you are building on micro-ATX or Mini-ITX and want the smaller footprint (35 L). Pick the H5 Flow if you need ATX or E-ATX, a GPU up to 410 mm, or a 360 mm front radiator (45 L).

H3 Flow vs H5 Flow at a glance

	H3 Flow	H5 Flow
Motherboard	Micro-ATX, Mini-ITX	E-ATX (up to 277 mm wide), ATX, Micro-ATX, Mini-ITX
Back-connect motherboards	Yes (micro-ATX)	No
Size (H x W x D)	400 x 225 x 389 mm	465 x 225 x 430 mm
Volume	35.0 L	45.0 L
GPU length	Up to 377 mm (no front fans), 352 mm (with front fans), 317 mm (with front radiator and fans)	Up to 410 mm
CPU cooler height	Up to 170 mm	Up to 170 mm
Front radiator	Up to 280 mm	Up to 360 mm (120 mm fans) or 280 mm (140 mm fans)
Top radiator	Up to 240 mm	Up to 240 mm, or 280 mm with low-profile memory
Fan mounts	Front 2 x 120/140 mm, top 2 x 120/140 mm, bottom 2 x 120 mm, rear 1 x 120 mm	Front 3 x 120 or 2 x 140 mm, top 2 x 120/140 mm, bottom 2 x 120 mm, rear 1 x 120 mm (up to 8)
PSU length	Up to 185 mm	Up to 200 mm
Warranty	2 years	2 years

Why build in the H3 Flow

The H3 Flow fits a full gaming build into 35 liters. You still get room for a GPU up to 377 mm, a 280 mm front radiator, and up to seven fans, plus back-connect micro-ATX support for a cleaner front side. It is a strong fit for small rooms, dorms, and desks where every inch counts.

See the H3 Flow.

Why step up to the H5 Flow

The H5 Flow adds 10 liters of space for ATX and E-ATX boards, GPUs up to 410 mm, a 360 mm front radiator, and room for up to eight fans. If you want the largest GPUs or a 360 mm AIO up front, this is the one.

See the H5 Flow and H5 Flow RGB.

Which one should you buy?

Choose the H3 Flow for micro-ATX or Mini-ITX, a smaller footprint, or a back-connect micro-ATX board.
Choose the H5 Flow for ATX or E-ATX, GPUs longer than 377 mm, or a 360 mm front radiator.

Still deciding on size? Read what size PC case you need, then plan airflow with how many case fans you need. Compare every model in NZXT PC cases.

Frequently asked questions

Is the H3 Flow micro-ATX?

Yes. The H3 Flow supports micro-ATX and Mini-ITX motherboards, including back-connect micro-ATX boards.

Can the H3 Flow fit a full-size GPU?

Yes. It fits GPUs up to 377 mm with no front fans, 352 mm with front fans, and 317 mm with a front radiator and fans.

What radiator fits in the H3 Flow?

Up to 280 mm in the front and up to 240 mm on top.

Is the H5 Flow bigger than the H3 Flow?

Yes. The H5 Flow is 45.0 L (465 x 225 x 430 mm) and the H3 Flow is 35.0 L (400 x 225 x 389 mm).

Does the H5 Flow support back-connect motherboards?

No. Back-connect support is on the H3 Flow for micro-ATX boards.