SWTX (Server / Workstation Technology eXtended) is a computer case and motherboard form factor that is longer but narrower than WTX. SWTX is a proprietary format used by Supermicro, primarily for 4-socket servers. SWTX motherboards are not compatible with (E)ATX cases because of their size and mounting scheme. Likewise, ATX motherboards are not compatible with SWTX cases. Dimensions: from 16 × 13 in (406 × 330 mm) to 18 × 13 in (457 × 330 mm). Most SWTX boards seem to be in the middle of this range, around 16.48 × 13 in (419 × 330 mm).
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SWTX Wikipedia(Text) CC BY-SA