EVGA Z370 MICRO User Manual page 19

EVGA Z370 MICRO (121-KS-E375)
23. CMOS Battery
The +3V CMOS battery backup provides uninterruptable power to the
BIOS/UEFI to store all its settings; otherwise, each power on would act as if
the BIOS was just reset. These batteries typically last several years and rarely
need to be replaced.
24. PC Speaker
This is a small mono low-fidelity speaker, which is permanently attached to the
motherboard. Its primary use is for debugging purposes. A POST beep may
indicate a successful POST or various tones for USB initialization, while other
beeps may indicate an issue during the POST process. Please see Page 123 for
more details.
25. Rear Panel I/O Connectors (Figure 2)
This is the section referred to as the I/O Hub. This panel contains the
hardwired USB, Sound, and Ethernet connections. Please see Page 13 for a
component level breakdown.
* There are two numeric references for PCI-Express: one is mechanical, which is the
actual slot-length footprint across the motherboard, while the second is electrical, which
is a reference to how many PCIe lanes are routed to the slot.
PCI Express was designed with a universal architecture; you can install x1 cards, such as
sound cards or USB controllers, into an x16 slot. Many types of cards can use various
numbers of PCIe lanes; similarly, some applications might only use certain parts of a
card (e.g. compute apps), requiring only a single PCIe lane to accomplish its task without
affecting performance. This is why there are x16 mechanical slots with an x1 electrical
PCIe lane. Using the entire length of a PCIe slot is unnecessary, nor does it cause an
adverse effect to use a shorter form-factor bus card in a slot that physically can hold a
larger form-factor bus card.
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